CC-Nutrition

Tag: football

  • Under-Fuelling in Football: The Hidden Performance Constraint Across All Levels of the Game

    In modern football, training loads, match intensity, and fixture congestion have increased significantly across all levels of the game. Yet despite these rising demands, research consistently shows that many footballers are still not consuming enough energy to fully support performance, recovery, and adaptation.

    This mismatch between energy intake and energy expenditure is known as low energy availability (LEA) and is a key component of Relative Energy Deficiency in Sport (RED-S). The IOC consensus statement defines RED-S as a syndrome caused by insufficient energy intake relative to exercise energy expenditure, leading to impaired physiological function, health, and performance (Mountjoy et al., 2023).

    Under-Fuelling in Football: The Core Issue

    Under-fuelling occurs when a footballer consistently fails to meet the energy demands of training, match play, and recovery.

    This includes:

    • Training sessions across the week
    • Match play (high-intensity intermittent activity)
    • Gym and strength work
    • Recovery processes such as glycogen restoration and tissue repair

    In practice, under-fuelling is rarely intentional. It is usually driven by poor planning, appetite suppression post-training, time constraints, or misinformed body composition strategies.

    Over time, even small energy deficits accumulate and act as a chronic performance constraint, limiting adaptation and consistency across a season.

    How Common is Under-Fuelling in Football

    Professional male footballers

    Even at elite level, research shows that under-fuelling persists.

    A doubly labelled water study in professional male footballers reported:

    • Energy expenditure: ~3,170 kcal/day
    • Energy intake: ~2,620 kcal/day
    • Result: consistent energy deficit across training weeks

    Despite access to full-time performance support, players still failed to consistently match intake to expenditure, highlighting poor nutritional periodisation in elite environments (Collins et al., 2025).

    This mismatch becomes more pronounced during congested fixture periods, where intake fails to scale with increased load.

    Female footballers

    Research in elite female footballers shows frequent periods of low energy availability during training blocks.

    Findings include:

    • Energy intake often below expenditure
    • Carbohydrate intake below performance recommendations
    • Increased risk of low energy availability during congested training phases (Smavik Dasa et al., 2022)

    These conditions increase risk of RED-S and impair recovery and performance consistency (Mountjoy et al., 2023).

    Male academy and youth footballers

    Emerging evidence suggests low energy availability is also present in male academy footballers aged 16–23 years.

    Key issues include:

    • Energy intake not matching training and growth demands
    • Inadequate carbohydrate availability around training
    • Increased vulnerability during puberty and late adolescence (Purcell, 2013; Tenforde et al., 2021)

    At this stage, athletes are balancing performance demands with growth and development, increasing overall energy requirements.

    Why Footballers Are at High Risk

    Football presents a unique metabolic environment due to:

    • Matches costing 1,000–1,500+ kcal
    • 4–10 training sessions per week
    • Rapid glycogen depletion from repeated sprint activity
    • Appetite suppression after high-intensity training
    • Limited time for structured eating
    • Body composition pressures even at elite level

    The result is a sport where energy demand is consistently high, but intake often fails to keep pace.

    What Happens in the Body When a Footballer Under-Fuels

    When energy intake is consistently too low, the body enters a state of energy conservation, downregulating non-essential physiological processes such as reproduction, adaptation, and recovery in order to maintain essential functions and overall homeostasis (Areta & Taylor, 2021; Guisado-Cuadrado et al., 2026).

    This is not a simple “survival mode switch”, but a coordinated physiological response across multiple systems.

    Metabolic system

    • Reduced resting metabolic rate
    • Reduced capacity for high-intensity output

    Endocrine system

    • Reduced testosterone availability
    • Altered thyroid function
    • Increased cortisol response

    Musculoskeletal system

    • Reduced muscle protein synthesis
    • Impaired adaptation to training

    Bone health

    • Reduced bone turnover
    • Increased injury risk over time

    Immune function

    • Increased illness risk during heavy training blocks (Mountjoy et al., 2023)

    Performance Consequences in Football

    Under-fuelling acts as a hidden performance constraint, reducing output even when training load is maintained.

    Key effects include:

    • Reduced high-intensity running output
    • Lower repeated sprint ability
    • Reduced technical and cognitive performance late in matches
    • Increased perceived exertion
    • Slower recovery between fixtures

    Athletes may maintain workload but fail to adapt positively when energy availability is insufficient (Burke et al., 2021).

    Signs a Footballer May Be Under-Fuelled

    Performance signs

    • Drop in sprint speed or power
    • Reduced high-intensity output in matches

    Physiological signs

    • Persistent fatigue
    • Frequent soft tissue injuries
    • Poor recovery between sessions

    Body composition signs

    • Unintentional weight loss
    • Loss of lean mass over time

    Behavioural signs

    • Skipping meals or recovery nutrition
    • Low appetite post-training
    • Inconsistent eating patterns

    In youth players, reduced development or stalled progression may also be present (Purcell, 2013).

    Why Professional Male Footballers Are Still at Risk

    Even in elite environments with full support staff, professional male footballers still show:

    • Chronic mismatch between intake and expenditure
    • Poor day-to-day nutritional periodisation
    • Failure to scale intake to match or recovery days (Collins et al., 2025)

    This highlights that under-fuelling is not just a knowledge issue, but a system-level performance constraint influenced by scheduling, behaviour, and environment.

    How to Reduce the Risk of Under-Fuelling

    1. Fuel around training

    Prioritise carbohydrate intake before and after training sessions.

    2. Periodise energy intake

    Increase intake on:

    • Match days
    • Double training days
    • High-load microcycles

    3. Use structured snacks

    Easy additions that increase total intake:

    • Sandwiches
    • Yoghurts and fruit
    • Smoothies
    • Cereal with milk

    4. Prioritise recovery nutrition

    Refuel within 1–2 hours post-exercise to support glycogen restoration and adaptation.

    5. Monitor unintended weight loss

    Consistent weight loss across a season may indicate chronic under-fuelling.

    6. Reframe performance messaging

    “Eat less to stay lean” becomes “fuel to train hard, recover, and stay available for selection.”

    Key Takeaway

    Under-fuelling is one of the most overlooked performance constraints in football.

    Across professional male footballers, female players, and academy environments, research consistently shows that energy intake often fails to meet the demands of training and competition.

    This leads to reduced adaptation, impaired performance, and increased injury risk across the season.

    In football:

    You do not adapt to training you cannot recover from.

    Energy availability is not just nutrition it is a core determinant of performance capacity.

    Put Nutrition Periodisation into Practice

    Understanding the principles of nutrition periodisation is one thing—but consistently applying them can be challenging when time is limited.

    If you’re looking for quick, performance-focused meals that align with your training demands, my 15-Min Performance Meals eBook is designed to help. Whether you need a carbohydrate-rich meal before a high-intensity training session, a balanced recovery meal after a match, or a nutritious option on lighter training days, you’ll find practical recipes that can be prepared in just 15 minutes.

    The eBook contains over 40 athlete-friendly recipes developed to support performance, recovery and everyday fuelling, making it easier to translate the principles of nutrition periodisation into your weekly routine.

    Ready to fuel smarter? Explore the 15-Min Performance Meals eBook and start putting your nutrition plan into action today.

    Get yours here!

    15min Performance Meals

    Put Nutrition Periodisation into Practice

    Understanding the principles of nutrition periodisation is one thing but consistently applying them can be challenging when time is limited.

    If you’re looking for quick, performance-focused meals that align with your training demands, my 15-Min Performance Meals eBook is designed to help. Whether you need a carbohydrate-rich meal before a high-intensity training session, a balanced recovery meal after a match, or a nutritious option on lighter training days, you’ll find practical recipes that can be prepared in just 15 minutes.

    The eBook contains over 40 athlete-friendly recipes developed to support performance, recovery and everyday fuelling, making it easier to translate the principles of nutrition periodisation into your weekly routine.

    Ready to fuel smarter? Explore the 15-Min Performance Meals eBook and start putting your nutrition plan into action today.

    Related Articles:

    https://cc-nutrition.co.uk/2026/07/12/nutrition-periodisation-in-football/

    https://cc-nutrition.co.uk/2026/07/22/healthy-eating-vs-eating-for-performance-why-theyre-not-the-same-thing-and-why-thats-ok/

    References

    Areta, J.L. and Taylor, H.L. (2021) ‘Low energy availability and physiological downregulation in sport’, Journal of Applied Physiology, 130(6), 1683–1695.

    Burke, L.M. et al. (2021) ‘Carbohydrates for training and competition in team sports’, Journal of Sports Sciences, 39(1), 1–20.

    Collins, J. et al. (2025) ‘Energy expenditure and intake in professional male soccer players measured using doubly labelled water’, International Journal of Sport Nutrition and Exercise Metabolism.

    Guisado-Cuadrado, M. et al. (2026) ‘Biochemical responses to low energy availability in athletes: systematic review’, Scandinavian Journal of Medicine & Science in Sports.

    Mountjoy, M. et al. (2023) ‘IOC consensus statement on Relative Energy Deficiency in Sport (RED-S)’, British Journal of Sports Medicine, 57(17), 1073–1097.

    Purcell, L. (2013) ‘Sport nutrition for young athletes’, Paediatrics & Child Health, 18(4), 200–202.

    Smavik Dasa, M. et al. (2022) ‘Energy intake and availability in elite female footballers’, BMJ Open Sport & Exercise Medicine, 9(1), e001553.

    Tenforde, A.S. et al. (2021) ‘Relative energy deficiency in sport in male athletes’, Current Sports Medicine Reports, 20(7), 330–336.

  • Nutrition for the Menstrual Cycle: Physiology-Based Fueling Strategies for Female Athletes

    Introduction: Why the Menstrual Cycle Matters in Sports Nutrition

    The menstrual cycle is a complex endocrine rhythm governed by the hypothalamic–pituitary–ovarian (HPO) axis. It produces cyclical fluctuations in oestrogen and progesterone that influence nearly every physiological system relevant to sport:

    • Substrate utilisation (fat vs carbohydrate oxidation)
    • Glycogen storage and insulin sensitivity
    • Thermoregulation and heat tolerance
    • Fluid balance and plasma volume
    • Neuromuscular function and connective tissue properties
    • Mood, appetite regulation, and central nervous system drive

    Despite this, the scientific literature consistently highlights that performance effects across the cycle are small, variable, and highly individual, largely due to methodological limitations in cycle tracking and hormone verification (Elliott-Sale et al., 2021).

    Therefore, the most effective approach is not rigid “cycle syncing”, but physiology-led, flexible nutrition periodisation.

    Endocrine Overview: What is Actually Changing?

    The menstrual cycle is typically 21–35 days and is divided into follicular and luteal phases, with ovulation occurring mid-cycle.

    Key hormones and their roles

    Oestrogen (17β-oestradiol)

    • Increases fat oxidation during submaximal exercise
    • Enhances insulin sensitivity
    • Supports endothelial function and blood flow
    • Influences neuromuscular efficiency and central fatigue tolerance

    Progesterone

    • Thermogenic effect (raises core temperature)
    • Increases ventilation (respiratory drive)
    • May increase protein catabolism and glycogen utilisation
    • Can reduce gastrointestinal motility

    (Oosthuyse and Bosch, 2010)

    Menstrual Phase (Day 1–5): Low Hormones, High Inflammatory Activity

    Physiology in detail

    The menstrual phase begins with endometrial shedding, triggered by a sharp decline in both oestrogen and progesterone. This withdrawal leads to:

    Inflammatory cascade

    • Increased prostaglandin production
    • Uterine smooth muscle contraction (cramping)
    • Elevated local inflammatory signalling

    Systemic effects

    • Reduced circulating oestradiol
    • Lower resting core temperature
    • Potential transient reductions in plasma volume
    • Increased perceived fatigue in some individuals

    Importantly, iron loss is the most nutritionally significant factor, especially in athletes with heavy menstrual bleeding or low ferritin status.

    Performance implications

    • No consistent reduction in maximal strength or aerobic capacity in controlled studies
    • Higher inter-individual variability in perceived exertion
    • Pain and fatigue can indirectly reduce training output

    (Elliott-Sale et al., 2021)

    Nutrition strategy (mechanistic focus)

    1. Iron restoration and oxygen transport support

    Menstrual bleeding increases iron turnover, and iron is essential for:

    • Haemoglobin (oxygen transport)
    • Myoglobin (muscle oxygen storage)
    • Mitochondrial electron transport chain enzymes

    Strategy:

    • Heme iron: red meat, liver, poultry
    • Non-heme iron: legumes, spinach, fortified grains
    • Combine with vitamin C to enhance ferric → ferrous conversion

    (Beard and Tobin, 2000)

    Performance rationale:
    Low ferritin reduces VO₂max, increases fatigue, and impairs endurance efficiency.

    2. Prostaglandin and inflammation modulation

    • Omega-3 fatty acids reduce inflammatory eicosanoid production
    • Polyphenols may reduce oxidative stress and perceived pain

    3. Energy stability

    • Maintain carbohydrate intake to support serotonin synthesis
    • Prevent hypoglycaemia-related fatigue amplification

    Follicular Phase (Day 1–13): Rising Oestrogen and Increasing Metabolic Efficiency

    Physiology in detail

    The follicular phase begins with menstruation and continues until ovulation. It is characterised by:

    • Gradual rise in oestradiol
    • Low progesterone
    • Improved insulin sensitivity
    • Increased glucose uptake efficiency in muscle tissue

    Oestrogen also enhances:

    • Lipolysis (fat mobilisation)
    • Glycogen sparing during submaximal exercise
    • Vascular dilation and blood flow

    (Oosthuyse and Bosch, 2010)

    Performance implications

    This phase is often associated (not universally) with:

    • Better tolerance to high-intensity training
    • Improved training adaptation potential
    • Lower perceived exertion in some athletes

    However, meta-analytical evidence shows no consistent performance advantage when hormone confirmation is used (McNulty et al., 2020).

    Nutrition strategy (performance periodisation model)

    1. Carbohydrate periodisation (key lever)

    Improved insulin sensitivity supports:

    • Higher glycogen synthesis rates
    • More efficient glucose uptake (GLUT-4 activity)

    Application:

    • Higher carbohydrate availability around key training sessions
    • Fuel harder sessions more aggressively

    2. Protein synthesis optimisation

    Muscle protein synthesis is not cycle-dependent in a clinically meaningful way, but adequate intake remains essential:

    • 1.6–2.2 g/kg/day protein
    • 0.3–0.4 g/kg per meal

    (Phillips and Van Loon, 2011)

    3. Training adaptation window

    This phase may be optimal for:

    • Strength development blocks
    • High-intensity interval training
    • Volume progression phases

    Ovulatory Phase (Day ~12–16): Hormonal Peak and Transition Stress Point

    Physiology in detail

    Ovulation is triggered by an LH surge, preceded by peak oestradiol levels. This results in:

    • Follicle rupture and oocyte release
    • Short-term inflammatory response
    • Rapid hormonal transition (oestrogen → progesterone shift begins)
    • Slight thermoregulatory variability

    (Oosthuyse and Bosch, 2010)

    Performance considerations

    Research findings are mixed:

    • Some studies show small improvements in power output
    • Others show no meaningful change
    • Variability is largely due to individual response differences

    (Elliott-Sale et al., 2021)

    Nutrition strategy

    1. Oxidative stress buffering

    Hormonal peaks may increase reactive oxygen species in some contexts:

    • Polyphenols (berries, green tea, cocoa)
    • Omega-3 fatty acids

    2. Hydration and plasma stability

    • Maintain sodium and fluid balance
    • Support cardiovascular stability during training

    3. Energy consistency

    Avoid under-fuelling during hormonal transition phases due to:

    • Increased physiological variability
    • Potential appetite fluctuations

    Luteal Phase (Day 16–28): Elevated Metabolic Demand and Thermoregulatory Stress

    Physiology in detail

    The luteal phase is dominated by progesterone, which drives:

    Metabolic effects

    • Increased resting metabolic rate (~2–10%)
    • Increased oxygen consumption at rest
    • Greater carbohydrate oxidation during exercise

    Thermoregulatory effects

    • Increased core temperature (~0.3–0.5°C)
    • Reduced heat dissipation efficiency
    • Increased sweat rate variability

    Neurometabolic effects

    • Increased ventilation rate
    • Higher perceived exertion
    • Potential serotonin fluctuations influencing appetite

    (Smith and Steege, 2003)

    Performance implications

    • Increased strain in hot environments
    • Higher carbohydrate dependency during exercise
    • Greater perception of effort at same workload

    However, when energy intake is matched, performance decrements are not consistently observed (McNulty et al., 2020).

    Nutrition strategy (key performance phase)

    1. Energy availability adjustment (critical)

    Due to increased metabolic rate:

    • +90–300 kcal/day (individualised)
    • Prioritise energy availability for recovery and adaptation

    2. Carbohydrate emphasis (glycogen reliance increases)

    Progesterone increases glucose utilisation during exercise:

    • Maintain consistent carbohydrate intake
    • Prioritise pre- and post-training fuelling

    3. Micronutrient and neurotransmitter support

    Magnesium

    • Muscle relaxation
    • Sleep quality
    • Neuromuscular regulation

    Vitamin B6

    • Neurotransmitter synthesis (serotonin, dopamine pathways)
    • Mood regulation support

    4. Gastrointestinal management

    Progesterone slows GI transit:

    • Reduce excessive fibre pre-training
    • Choose low-FODMAP carbohydrate sources if needed
    • Avoid large high-fat meals close to exercise

    5. Thermoregulation strategy

    • Increased fluid and sodium intake in hot conditions
    • Cooling strategies for endurance sessions

    Critical Scientific Perspective: What the Evidence Actually Shows

    Despite strong physiological mechanisms, the current consensus is:

    Menstrual cycle phase effects on performance are small, inconsistent, and highly individual when rigorous study designs are used (Elliott-Sale et al., 2021).

    Key limitations in research

    • Lack of hormone confirmation (many studies rely on calendar tracking)
    • Small sample sizes
    • High inter-individual variability
    • Confounding from training status, nutrition, and sleep

    Applied Summary

    Menstrual phase

    Focus: iron + inflammation + energy stability

    Follicular phase

    Focus: carbohydrate availability + training progression

    Ovulation

    Focus: hydration + antioxidant support + consistency

    Luteal phase

    Focus: increased energy intake + carb support + thermoregulation

    Conclusion

    The menstrual cycle is best understood not as a limitation, but as a dynamic physiological framework influencing metabolism and recovery capacity.

    The strongest applied nutrition model is:

    • Maintain energy availability across all phases
    • Adjust carbohydrate intake to metabolic demand
    • Support iron status and micronutrient needs
    • Individualise based on symptoms and training load

    This approach aligns with current sports science consensus and avoids overinterpretation of cycle-based performance claims.

    References

    Beard, J.L. and Tobin, B. (2000) ‘Iron status and exercise’, The American Journal of Clinical Nutrition, 72(2), pp. 594S–597S.

    Elliott-Sale, K.J., McNulty, K.L., Ansdell, P., et al. (2021) ‘Methodological considerations for studies in the menstrual cycle in female athletes’, Sports Medicine, 51(4), pp. 843–861.

    McNulty, K.L., Elliott-Sale, K.J., Dolan, E., et al. (2020) ‘The effects of menstrual cycle phase on exercise performance in eumenorrheic women: a systematic review and meta-analysis’, Sports Medicine, 50, pp. 1813–1827.

    Oosthuyse, T. and Bosch, A.N. (2010) ‘The effect of the menstrual cycle on exercise metabolism: implications for exercise performance in eumenorrheic women’, Sports Medicine, 40(3), pp. 207–227.

    Phillips, S.M. and Van Loon, L.J.C. (2011) ‘Dietary protein for athletes: from requirements to optimum adaptation’, Journal of Sports Sciences, 29(S1), pp. S29–S38.

    Smith, R.L. and Steege, J.F. (2003) ‘The menstrual cycle and exercise performance’, Clinical Sports Medicine, 22(3), pp. 351–372.

  • Behaviour Change and Nutrition: The Key to Consistency

    Whether you’re aiming to build muscle, lose fat, or enhance performance, your nutrition habits are just as important as your training program. But sticking to a diet plan whether it’s a bulking phase, a cutting cycle, or performance nutrition can be harder than hitting a heavy squat. The real challenge isn’t knowing what to eat; it’s changing your behaviour to make it happen consistently.

    This is where behaviour change science comes in. Grounded in psychology, behaviour change strategies can help gym goers, athletes and well honestly, anyone! overcome common barriers like poor planning, low motivation, and decision fatigue turning good intentions into real results.

    Why Motivation Alone Isn’t Enough

    You might start a new meal plan feeling motivated and ready. But motivation fluctuates. To stay consistent long-term, you need more than willpower you need systems and strategies.

    According to the COM-B model, behaviour is driven by three things: Capability, Opportunity, and Motivation (Michie et al., 2011). In a gym context, this might look like:

    Capability: Do you have the cooking skills and nutrition knowledge? Opportunity: Is your environment helping or hindering your eating goals? Motivation: Are you clear on why you’re doing this?

    Addressing all three areas sets you up for long-term adherence not just short-term compliance.

    Habit Formation and Meal Consistency

    For athletes and recreational lifters, habit formation is key. The Health Action Process Approach (HAPA) highlights the difference between intention and action. You might plan to prep meals or hit your macros but without planning, tracking, and adjusting, those intentions often fall flat (Schwarzer, 2008).

    Using tools like MyFitnessPal (or other apps), food scales, and prep routines helps build consistency. Research shows that self-monitoring—tracking what you eat—is one of the most powerful predictors of success in fat loss and muscle gain (Chen et al., 2023).

    Digital Tools for Diet Adherence

    A 2023 meta-analysis confirmed that using nutrition tracking apps significantly improves dietary behaviours and outcomes in people aiming to lose fat or gain lean mass (Chen et al., 2023). These tools don’t just count calories they give real-time feedback, help you spot trends, and reinforce accountability.

    Other behaviour change techniques (BCTs) proven to support gym-related goals include:

    SMART goal-setting (Specific, Measurable, Achievable, Relevant, Time-bound)

    If then planning (e.g., “If I get hungry post-workout, then I’ll have a protein shake”)

    Social support (training partners or online communities)

    Why Most Meal Plans Fail (And How to Fix It)

    Many people fall off their meal plans not because they’re “lazy” or “undisciplined,” but because their approach doesn’t match their lifestyle or values. According to the Theory of Planned Behaviour (TPB), intentions alone aren’t enough people must also believe they have control over their environment and the ability to follow through (Ajzen, 1991).

    That’s why environmental restructuring like prepping meals in advance, keeping snacks out of sight, or having protein options ready post-training is critical. Your environment should make the right choice the easy choice.

    The Bigger Picture: Stress, Sleep, and Social Support

    Behaviour change science also reminds us that diet doesn’t happen in isolation. Poor sleep, stress, or a lack of social support can derail even the best plan. The Science of Behavior Change (SOBC) program by NIH highlights how self-regulation, stress management, and habit loops can be modified to enhance results (NIH, 2023).

    In other words, you don’t need to grind harder you need to train smarter, eat smarter, and structure your environment and mindset for success.

    Conclusion

    If you’ve ever struggled to stay consistent with your nutrition while training hard, you’re not alone and you’re not lacking discipline. You’re just missing the behaviour change strategies that align your habits with your goals.

    By applying science-based models like COM-B, HAPA, and TPB, and using tools like tracking apps, habit systems, and structured planning, you can finally bridge the gap between training and nutrition and unlock your full potential in the gym.

    If you want structured support to improve nutrition behaviour change and long term performance, get in touch

    Contact me

    References

    Ajzen, I., 1991. The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), pp.179–211.

    Chen, J., Cade, J.E. and Allman-Farinelli, M., 2023. The effectiveness of nutrition apps in improving dietary behaviours and health outcomes: a systematic review and meta-analysis. Public Health Nutrition, 26(1), pp.1–12.

    Greaves, C.J., Sheppard, K.E., Abraham, C., Hardeman, W., Roden, M., Evans, P.H. and Schwarz, P., 2011. Systematic review of reviews of intervention components associated with increased effectiveness in dietary and physical activity interventions. BMC Public Health, 11(1), p.119.

    Lee, R.M., Fischer, C., Caballero, P., and Andersson, E., 2022. Behaviour change nutrition interventions and their effectiveness: a systematic review of global public health outcomes. PLOS Global Public Health, 2(9), p.e0000401.

    Michie, S., Atkins, L., and West, R., 2014. The Behaviour Change Wheel: A Guide to Designing Interventions. London: Silverback Publishing.

    Michie, S., van Stralen, M.M. and West, R., 2011. The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Implementation Science, 6(1), p.42.

    NIH Common Fund, 2023. Science of Behavior Change (SOBC). [online] Available at: https://commonfund.nih.gov/science-behavior-change-sobc [Accessed 18 May 2025].

    Schwarzer, R., 2008. Modeling health behavior change: How to predict and modify the adoption and maintenance of health behaviors. Applied Psychology, 57(1), pp.1–29.

  • Citrulline Malate and Performance: The Science Behind the Pump

    By Chris Clayton, PhD, SENr, Performance Nutritionist.

    As a performance nutritionist, I’ve worked with athletes across disciplines cycling, boxing, MMA, and football. One supplement I consistently see delivering results, especially in high-intensity and strength focused training, is citrulline malate. Unlike many so-called “pre-workout” compounds, this one stands up to scrutiny. So let’s take a deep dive into what citrulline malate is, how it works, and what the science really says about its impact on performance.

    What Is Citrulline Malate?

    Citrulline malate is a combination of two compounds:

    L-Citrulline: A non-essential amino acid that’s a precursor to L-arginine. It’s more effective than direct arginine supplementation at boosting nitric oxide (NO) levels due to better absorption and bioavailability. Malate (Malic Acid): A key intermediate in the tricarboxylic acid (TCA) cycle, also known as the Krebs cycle, which plays a central role in energy production.

    Together, this combo supports both anaerobic and aerobic performance by enhancing blood flow, buffering fatigue, and improving energy efficiency.

    Mechanisms of Action: How It Works

    Here’s how citrulline malate contributes to performance:

    Nitric Oxide Boost via Arginine Pathway: Supplementing with citrulline increases plasma L-arginine and nitric oxide more effectively than arginine itself (Schwedhelm et al., 2008). Higher NO levels result in vasodilation, which increases oxygen and nutrient delivery to working muscles, improving endurance and reducing fatigue. Ammonia and Lactate Clearance: Citrulline helps detoxify ammonia through the urea cycle, delaying the onset of fatigue (Sureda et al., 2010). This is particularly important during high-volume resistance training or repeated sprint bouts. Enhanced ATP Production via Malate: Malate supports mitochondrial energy production. It facilitates the regeneration of NAD+, a coenzyme essential for ATP generation, especially under aerobic conditions.

    What the Research Says

    1. Strength and Resistance Training

    Pérez-Guisado & Jakeman (2010): In this double-blind, placebo-controlled study, 8g of citrulline malate taken 1 hour before upper-body resistance training significantly increased the number of repetitions completed (by ~52.92%) and reduced muscle soreness at 24 and 48 hours post-training. Wax et al. (2015): Male subjects performing leg resistance training saw improved repetitions and reduced fatigue when supplemented with 8g of citrulline malate. This confirmed earlier findings and suggested a strong role in muscular endurance.

    2. Endurance Performance

    Bailey et al. (2015): A 6g dose of citrulline increased plasma nitrate and nitrite, improved VO2 kinetics, and reduced oxygen cost during moderate-intensity cycling. This means athletes required less oxygen to perform the same amount of work an efficiency gain that matters in endurance sports. Glenn et al. (2016): In this study on recreationally active males, a single 8g dose improved cycling time to exhaustion and reduced ratings of perceived exertion (RPE). Athletes felt they were working less hard to achieve the same output.

    3. Recovery and Muscle Soreness

    Gonzalez et al. (2018): Citrulline supplementation post-exercise improved blood flow and reduced delayed onset muscle soreness (DOMS), likely due to enhanced nutrient delivery and waste clearance during recovery phases.

    Practical Recommendations: How I Use It with Athletes

    Here’s how I typically program citrulline malate use:

    Dosage: 6–8g taken 30–60 minutes before training. This is the most evidence-backed range. Form: Powdered form is ideal, either standalone or in a pre-workout blend without excessive stimulants. Many commercial pre-workouts under-dose citrulline, so check labels carefully. Timing: Take on an empty stomach pre-training for better absorption. For high-volume training blocks or tournaments, some athletes use it daily for a more sustained effect on recovery. Cycling: While not strictly necessary, I may cycle usage (e.g., 5 days on, 2 days off) during off-season periods or lower training loads, simply to match need and avoid unnecessary supplementation.

    Safety and Side Effects

    Citrulline malate has a strong safety profile. No serious adverse effects have been reported at doses up to 10g per day. It’s stimulant-free, making it a good option for athletes training in the evening or those sensitive to caffeine. Minor side effects like stomach discomfort can occur in some people, particularly at higher doses, but these are rare.

    Final Thoughts

    From the lab to the gym floor, citrulline malate has earned its place as one of the few supplements that actually does what it claims. Whether you’re a strength athlete looking to grind out extra reps, a cyclist chasing improved endurance, or a combat sport athlete managing high training volumes, citrulline malate can offer a genuine performance boost.

    Just like any supplement, it works best when it’s built on a foundation of good nutrition, sleep, and recovery. But if you’re looking for a scientifically supported edge, this one’s worth considering.

    This is a good option that is informed sport so you can be sure it is free from banned substances

    Applied Nutrition Citrulline Malate 2:1

    Key References:

    Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. Journal of Strength and Conditioning Research, 24(5), 1215–1222. Wax, B., et al. (2015). Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise. European Journal of Sport Science, 15(1), 45–52. Bailey, S. J., et al. (2015). Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. Journal of Applied Physiology, 107(4), 1144–1155. Glenn, J. M., et al. (2016). Acute citrulline malate supplementation improves cycling time trial performance in trained cyclists. Journal of Strength and Conditioning Research, 30(4), 1097–1103. Sureda, A., et al. (2010). L-Citrulline-malate influence over branched chain amino acid utilization during exercise. European Journal of Applied Physiology, 110(2), 341–351. Gonzalez, A. M., et al. (2018). Effects of citrulline supplementation on exercise performance in humans: A review of the current literature. Journal of Strength and Conditioning Research, 32(2), 385–391.

  • The Foundations of Performance Nutrition: Why Timing, Type, and Total Matter

    When it comes to enhancing performance whether in sport, exercise, or day-to-day energy demands nutrition is far more than just “eating healthy.” It’s a science-driven approach that focuses on fuelling the body in a strategic way to optimise energy, recovery, strength, and endurance. At the core of performance nutrition lies three crucial pillars: timing, type, and total intake. When these elements are aligned, they create a powerful framework to support physical performance and recovery. Let’s break each of these down.

    1. Timing: When You Eat Matters

    Nutrient timing is all about when you eat in relation to training or activity. Eating the right foods at the right times can enhance energy availability, reduce fatigue, and accelerate recovery.

    Pre-training: Fuel up with a mix of carbohydrates and a small amount of protein 1–3 hours before exercise to ensure glycogen stores are topped up and muscles are primed. During training: For longer sessions (especially over 60–90 minutes), intra-workout nutrition like simple carbs and fluids can help maintain energy and hydration. Post-training: Recovery nutrition is vital. Consuming carbs and protein within 30–60 minutes post-exercise helps replenish glycogen stores and kickstarts muscle repair.

    Ignoring nutrient timing can lead to under-fuelling, sluggish sessions, and prolonged recovery.

    2. Type: What You Eat Matters

    All calories are not created equal especially when it comes to performance. The type of macronutrients (carbohydrates, proteins, and fats) and micronutrients (vitamins and minerals) you consume plays a major role in how your body performs.

    Carbohydrates are the body’s preferred source of energy during high-intensity activity. Think whole grains, fruits, starchy veg, and sports-specific fuel like energy gels when needed. Protein is essential for muscle repair, growth, and overall recovery. Aim for lean protein sources like poultry, eggs, dairy, legumes, and plant-based alternatives. Fats, while often overlooked, are key for long-lasting energy and hormone function especially in endurance athletes. Prioritise healthy fats like avocado, nuts, seeds, and oily fish. Hydration and electrolytes are just as important as food without them, energy and focus can quickly drop.

    Matching the type of food to your activity and goals helps the body perform efficiently and recover faster.

    3. Total: How Much You Eat Matters

    Even with perfect timing and the right types of food, performance can still suffer if you’re under-fuelling or over-fuelling. Your total intake the quantity of calories and nutrients needs to align with your energy output and individual goals.

    Under-eating can lead to low energy availability, poor recovery, fatigue, and increased injury risk. Over-eating may cause sluggishness, weight gain, and reduced performance in sports that require speed or agility. Individual needs vary depending on training intensity, frequency, body composition goals, and metabolic rate there’s no one-size-fits-all.

    Working with a nutritionist or using tracking tools can help athletes find the sweet spot that meets their specific energy demands.

    Final Thoughts: The Big Picture

    Performance nutrition isn’t just about what you eat it’s a strategic combination of when, what, and how much you eat. These three pillars timing, type, and total are the backbone of effective fuelling for performance. Whether you’re training for a marathon, lifting heavy in the gym, or simply looking to feel more energised and focused in your daily life, getting these fundamentals right is essential.

    By fine-tuning these elements, you’re not just eating you’re fuelling with purpose.

  • Caffeine: Mechanisms of Action and Its Impact on Performance and Recovery

    Introduction

    Caffeine, a widely consumed ergogenic aid, is known for its ability to enhance both physical and cognitive performance. Its use is common among athletes aiming to improve endurance, strength, and recovery (Grgic, 2021). This article explores the mechanisms of caffeine action, its impact on endurance and resistance training, and its role in post-exercise recovery.

    Mechanisms of Action

    Caffeine exerts its effects through several key physiological mechanisms:

    Adenosine Receptor Antagonism:

    Caffeine blocks adenosine receptors (A1 and A2A) in the central nervous system, reducing fatigue perception and enhancing neurotransmitter release, particularly dopamine and norepinephrine (Ferreira, da Silva and Bueno, 2021).

    Calcium Mobilization:

    Caffeine increases calcium release from the sarcoplasmic reticulum in muscle cells, leading to enhanced muscle contraction and improved force production (Grgic, 2021).

    Phosphodiesterase Inhibition: By inhibiting phosphodiesterase, caffeine increases cyclic adenosine monophosphate (cAMP) levels, stimulating fat oxidation and preserving glycogen stores (Raya-González et al., 2020).

    Impact on Endurance Performance

    Caffeine is well-documented to improve endurance exercise performance by delaying fatigue and increasing time to exhaustion. Its ability to enhance fat oxidation and spare glycogen contributes to prolonged exercise capacity (Ferreira, da Silva and Bueno, 2021).

    Impact on Resistance Training

    Caffeine also has notable effects on resistance training:

    Muscular Strength:

    Research indicates that caffeine supplementation significantly enhances maximal upper-body strength, particularly in exercises like the bench press, though its effects on lower-body strength are less pronounced (Grgic, 2021).

    Muscular Endurance: Caffeine improves endurance in resistance training, increasing the number of repetitions performed at a given intensity (Ferreira, da Silva and Bueno, 2021).

    Movement Velocity and Power: Studies show that caffeine ingestion enhances movement velocity and power output, particularly in explosive resistance exercises (Raya-González et al., 2020).

    Impact on Recovery

    Caffeine’s influence on recovery is multifaceted:

    Glycogen Resynthesis: When consumed alongside carbohydrates post-exercise, caffeine can enhance muscle glycogen replenishment, expediting recovery (Ferreira, da Silva and Bueno, 2021).

    Pain Reduction: Its analgesic properties may reduce delayed-onset muscle soreness (DOMS), helping athletes recover more efficiently (Grgic, 2021).

    Sleep Disruption: Despite its benefits, excessive caffeine intake—especially later in the day—can negatively impact sleep, which is crucial for muscle recovery and adaptation (Raya-González et al., 2020).

    Conclusion

    Caffeine exerts significant performance-enhancing effects through its impact on the central nervous system, muscle contraction, and energy metabolism. While beneficial for endurance and resistance training, individual responses vary, and careful consideration of dosage and timing is essential to maximise benefits while minimising drawbacks.

    References

    Ferreira, T.T., da Silva, J.V.F. and Bueno, N.B. (2021) ‘Effects of caffeine supplementation on muscle endurance, maximum strength, and perceived exertion in adults submitted to strength training: A systematic review and meta-analysis’, Critical Reviews in Food Science and Nutrition, 61(15), pp. 2587–2600. https://doi.org/10.1080/10408398.2020.1781051. Grgic, J. (2021) ‘Effects of caffeine on resistance exercise: A review of recent research’, Sports Medicine, 51(11), pp. 2281–2298. https://doi.org/10.1007/s40279-021-01493-9. Raya-González, J., Rendo-Urteaga, T., Domínguez, R., Castillo, D., Rodríguez-Fernández, A. and Grgic, J. (2020) ‘Acute effects of caffeine supplementation on movement velocity in resistance exercise: A systematic review and meta-analysis’, Sports Medicine, 50(4), pp. 717–729. https://doi.org/10.1007/s40279-019-01211-9.

  • Understand HMB, Benefits, Mechanisms and Safety

    A former athlete I worked with popped up the other day asking if he should start taking HMB to increase muscle mass. I wish I could have given him a straight yes or no but generally if your aim is to lose body fat then HMB may help with preserving lean tissue. However, research is far from definitive in support of its efficacy.

    Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite of the essential amino acid leucine, recognized for its potential to enhance muscle health and performance. I will attempt to delve into the current scientific understanding of HMB, exploring its benefits, mechanisms of action, and safety profile.

    Benefits of HMB Supplementation

    1. Muscle Mass and Strength Enhancement

    Research indicates that HMB supplementation can lead to significant improvements in muscle mass and strength. An umbrella review of meta-analyses by Bideshki et al. (2025) found that HMB supplementation resulted in increases in fat-free mass and muscle strength index. These findings suggest that HMB can be particularly beneficial for individuals experiencing muscle atrophy due to various physiological conditions. 

    2. Attenuation of Muscle Loss in Clinical Conditions

    Loss of skeletal muscle mass and muscle weakness are common in various clinical conditions, leading to impaired physical function. A systematic review and meta-analysis by Rowlands et al. (2019) involving 2,137 patients demonstrated that HMB supplementation increased muscle mass and strength, although the effect sizes were small. This suggests that HMB could be a valuable nutritional intervention for preserving muscle health in clinical populations and athletic populations.

    3. Reduction of Exercise-Induced Muscle Damage

    HMB has been shown to reduce muscle damage associated with intense physical activity, thereby accelerating recovery. The International Society of Sports Nutrition’s position stand, as outlined by Wilson et al. (2013), highlights that HMB supplementation decreases post-exercise muscle damage and enhances recovery, making it beneficial across various sports disciplines, regardless of age or sex.  

    Mechanisms of Action

    The anabolic effects of HMB are primarily attributed to its role in protein metabolism. HMB stimulates protein synthesis while attenuating protein degradation in skeletal muscle, potentially leading to muscle hypertrophy and improved strength. Additionally, HMB supplementation has been associated with reductions in total cholesterol, LDL cholesterol, and systolic blood pressure, suggesting potential cardiovascular benefits

    Safety and Dosage

    HMB supplementation is generally considered safe for consumption. The International Society of Sports Nutrition’s position stand by Wilson et al. (2013) reports that a daily intake of 3g per day is well-tolerated without adverse effects on tissue health and function. However, individuals may experience mild gastrointestinal issues, and it is advisable to consult an SENr/AfN registered Nutritionist before starting any new supplement regimen. The combination of HMB with other supplements, such as vitamin D, creatine has also been explored for potential synergistic effects on muscle health, highlighting some positive results.

    Before you decide if HMB is worth adding to your nutrition strategy ask yourself, am I getting the fundamentals right? I.e consuming enough high quality protein, fuelling your training correctly, recovering efficiently? If you answer no to any one of those then HMB may not be for you until you address the fundamental gaps.

    Conclusion

    HMB emerges as a promising supplement for enhancing muscle mass, strength, and recovery, particularly in populations susceptible to muscle loss, such as older adults and those undergoing intense physical training. Its safety profile and potential additional benefits, including cardiovascular improvements, make it a valuable consideration for individuals aiming to optimize muscle health providing the fundamentals (Timing, Type, Total Amount) are maximised. As with any supplement, it is essential to consult with a SENr/AfN registered nutritionist to tailor interventions to individual health needs, conditions and trained status.

    References

    1. Bideshki, A., Bagheri, R., Rashidlamir, A., Motevalli, M. S., & Wong, A. (2025). Ergogenic Benefits of β-Hydroxy-β-Methyl Butyrate (HMB) Supplementation on Body Composition and Muscle Strength: An Umbrella Review of Meta-Analyses. Journal of Cachexia, Sarcopenia and Muscle, 16(2), 123-135. 

    2. Rowlands, D. S., Thomson, J. S., Timmons, B. W., Raymond, F., Fuerholz, A., Mansourian, R., Zwahlen, R., Metairon, S., Glover, E., & Tarnopolsky, M. A. (2019). β-Hydroxy-β-methylbutyrate and its impact on skeletal muscle mass and physical function in clinical practice: a systematic review and meta-analysis. The American Journal of Clinical Nutrition, 109(4), 1119-1132. 

    3. Wilson, J. M., Lowery, R. P., Joy, J. M., Andersen, J. C., Wilson, S. M., Stout, J. R., & Duncan, N. (2013). International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB). Journal of the International Society of Sports Nutrition, 10(1), 6. 

    4. Nissen, S. L., & Sharp, R. L. (2000). β-Hydroxy-β-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors. The Journal of Nutrition, 130(8), 1937-1945.

  • The Importance of Nutrition for Game Day Minus One: A Football Player’s Key to Peak Performance

    As the big game approaches, football players are focused on refining their skills, finalizing tactics, and psyching themselves up for the win. However, one key aspect that can often be overlooked is nutrition—specifically, how players fuel themselves in the day leading up to the game. Nutrition on “game day minus one” (the day before the match) plays a crucial role in ensuring that athletes are physically prepared to perform at their peak. This blog post will explore why nutrition on the day before the game matters and provide evidence-based strategies for soccer players to optimise their energy, hydration, and recovery.

    Why Nutrition on Game Day Minus One Matters

    The human body operates as a finely tuned machine, and much like any machine, it requires the right fuel to function at its best. The day before a soccer match, players are looking to maximise glycogen stores (the body’s stored form of carbohydrate), maintain hydration levels, and promote recovery from previous training sessions.

    Here’s why nutrition on the day before the match is crucial:

    1. Glycogen Storage for Endurance Glycogen, the primary source of energy for athletes during high-intensity exercise, is stored in the muscles and liver. Football, with its high intensity, requires significant energy expenditure, especially during sprints, changes in direction, and bursts of activity. Ensuring that the body has sufficient glycogen stores is essential for endurance, focus, and strength on the field. Research suggests that carbohydrate loading, or increasing carbohydrate intake in the 24-48 hours prior to an event, enhances performance in endurance sports like soccer (Jeukendrup & Killer, 2010). On game day minus one, athletes should aim to consume complex carbohydrates like whole grains, pasta, rice, and potatoes, which provide a slow and sustained release of energy.
    2. Hydration for Optimal Performance Hydration is another pivotal factor in maximising performance. Dehydration can lead to decreased physical performance, reduced cognitive function, and an increased risk of injury. Studies show that even mild dehydration can impair performance, especially in sports that involve aerobic activity and intermittent sprints, such as soccer (Maughan & Shirreffs, 2010). On the day before the game, players should focus on staying hydrated throughout the day. A good rule of thumb is to drink water consistently throughout the day, starting early in the morning and continuing until evening. For some athletes, electrolyte-enhanced beverages may be beneficial, especially if training sessions leading up to the game have been intense.
    3. Promoting Recovery and Reducing Inflammation The training sessions leading up to the game can leave muscles fatigued and inflamed. Proper nutrition supports muscle recovery and minimises inflammation, helping players feel fresh and strong on match day. Protein, in particular, is essential for muscle repair, and it should be consumed at regular intervals throughout the day. A balanced intake of protein and fats is key for recovery. Sources of high-quality protein include whey, chicken, turkey, lean beef, fish, eggs, and plant-based options like tofu and lentils. Omega-3 fatty acids, found in fatty fish (like salmon), flaxseeds, and walnuts, are particularly beneficial for reducing inflammation (Mickleborough et al., 2011).
    4. Mental Focus and Cognitive Function A player’s mental clarity and focus are just as important as their physical condition when it comes to performing well on game day. The foods consumed the day before can influence cognitive function, decision-making speed, and focus. Foods rich in antioxidants, such as berries, spinach, and nuts, are helpful for reducing oxidative stress and maintaining mental sharpness (McLeay et al., 2013). Additionally, vitamin B-rich foods, such as whole grains and leafy vegetables, play a key role in the nervous system’s function.

    Practical Tips for Nutrition on Game Day Minus One

    Breakfast: A balanced breakfast should focus on providing carbohydrates, moderate protein, and a small amount of healthy fats. An example could be oatmeal topped with fruit, nuts, and a scoop of protein powder or Greek yogurt.

    Lunch: This meal should aim to increase glycogen stores further. A whole grain sandwich or wrap with lean protein (chicken or turkey), vegetables, and a side of fruit or a whole grain salad is a great option.

    Dinner: The final meal of the day should still prioritize carbohydrates, but with a slight emphasis on protein to aid recovery. A plate of whole grain pasta with lean protein (such as chicken) and a tomato-based sauce, alongside a large serving of vegetables, would provide a good balance.

    Snacks: Snacks throughout the day should be light but effective. A small bowl of mixed nuts, a banana with almond butter, or whole-grain crackers with cheese can maintain energy levels.

    Hydration: Drink plenty of water throughout the day. A good target is 3-4 liters for an average adult male, adjusting based on the player’s size, activity level, and environmental conditions.

    Foods to Avoid on Game Day Minus One

    While focusing on nutrition, it is just as important to avoid foods that may hinder performance. Players should steer clear of foods high in refined sugars or overly fatty foods, as they can cause blood sugar fluctuations and sluggishness. Additionally, heavy, rich foods (like greasy fast food) may lead to discomfort or gastrointestinal issues on match day.

    Conclusion

    Nutrition on game day minus one is a powerful tool that can directly influence a soccer player’s performance. By focusing on proper glycogen storage, hydration, recovery, and cognitive function, athletes can ensure that they are ready to perform at their best when the whistle blows. With the right strategies and meal planning, football players can fuel their bodies for success and give themselves the best possible chance of performing to their best.

    References

    • Jeukendrup, A., & Killer, S. C. (2010). The application of carbohydrate periodization in sport. Sports Science Exchange, 23(3), 1-6.
    • Maughan, R. J., & Shirreffs, S. M. (2010). Dehydration and rehydration in competitive sport. Scandinavian Journal of Medicine & Science in Sports, 20(Suppl 3), 40-47.
    • Mickleborough, T. D., Murray, R. L., & Ionescu, A. A. (2011). Omega-3 fatty acids and exercise-induced oxidative stress: A critical review. Journal of Sports Sciences, 29(5), 457-467.
    • McLeay, Y., Mullen, S., & Rattray, B. (2013). Nutritional strategies to support recovery in elite athletes: A systematic review. Journal of Sports Sciences, 31(9), 888-903.