The Endocrinology of Strongman: Hormones That Influence Mass, Strength and Recovery - Episode 10: What Happens Hormonally During a Caloric Surplus

1. A caloric surplus is more than a number of calories

When energy intake exceeds the body's needs for a period of time, physiology enters a different state from energy deficit. Nutrient availability changes, satiety signals shift, insulin secretion rises after meals, substrate handling changes, and the body can support energetically expensive processes such as tissue synthesis and recovery more easily.

For a Strongman, a surplus can be a tool for gaining muscle mass and supporting training. But the presence of extra energy does not mean every extra calorie becomes muscle. The body distributes energy between tissues, storage, and metabolic expenditure.

2. Insulin rises with intake

During increased food intake, especially when carbohydrate and energy intake are higher, insulin secretion can be greater than during restriction. Insulin facilitates glucose uptake, glycogen storage, and temporarily reduces lipolysis.

This is normal physiology. Higher insulin after meals does not automatically mean insulin resistance and does not mean that food is automatically converted into fat. Long-term energy context remains crucial.

3. Leptin detects larger energy reserves

Leptin is produced mainly by adipose tissue and signals the brain about energy stores. With overfeeding and increased fat mass, leptin can rise.

In theory, this signal should reduce food intake and support energy expenditure. In practice, leptin sensitivity varies, and prolonged overfeeding can raise leptin without producing a proportional suppression of appetite.

4. Ghrelin tends to be suppressed after overfeeding

Ghrelin is one of the signals involved in hunger and meal initiation. During increased intake, its dynamics can change, and post-meal suppression contributes to satiety.

Appetite, however, is not controlled by one hormone. Signals from the gut, adipose tissue, pancreas, and brain operate as a network.

5. A surplus can support tissue synthesis

Building muscle is energetically expensive. A surplus provides more energy for protein synthesis, glycogen restoration, tissue remodeling, and other adaptive processes.

An energy surplus still cannot replace mechanical stimulus. The literature indicates that hypertrophy emerges from the interaction of training, protein intake, energy, recovery, and individual characteristics, while an optimal surplus remains difficult to define universally.

6. Insulin and muscle mass: important, but not magical

Insulin has anti-catabolic effects and supports nutrient storage. In the presence of amino acids and training stimulus, it contributes to a metabolic environment that supports recovery.

But a larger insulin spike does not automatically mean a larger rate of hypertrophy. Research on the endocrine contribution to hypertrophy shows that the relationship between circulating hormones and muscle growth is much more complex than “more hormone equals more muscle.”

7. GH and IGF-1 in an energy-adequate environment

The GH/IGF-1 axis operates in a context strongly influenced by energy and nutrient availability. Unlike severe energy restriction, adequate energy availability can support IGF-1 production and action.

Even so, GH and IGF-1 should not be treated as a simple hypertrophy meter. They participate in metabolism, growth, and tissue remodeling, and their effects depend on tissue, receptor signaling, and context.

8. Testosterone can benefit from energy sufficiency

In men, sufficient energy availability supports normal hypothalamic-pituitary-gonadal function. Severe energy restriction and energy stress can contribute to central testosterone suppression, so returning to energy sufficiency removes one of the scarcity signals.

This does not mean that every surplus automatically produces higher testosterone. The relationship is influenced by body composition, sleep, stress, training, age, and metabolic health.

9. The thyroid and energy availability

When the body is no longer in an energy deficit, signals associated with energy conservation can ease. This may favor a thyroid profile consistent with better energy availability.

But a surplus should not be used to “force the thyroid.” Thyroid hormones respond to a wider regulatory network, and excessive overfeeding can add fat without producing proportional performance benefits.

10. What happens to insulin sensitivity

A controlled surplus in an active athlete is not the same as chronic overfeeding in a sedentary person. Trained muscle remains a major site for glucose disposal, and physical activity supports carbohydrate use and storage.

Over the long term, however, a very large surplus, excessive adipose gain, and reduced activity can contribute to impaired insulin sensitivity. The issue is therefore not the existence of a surplus, but its dose, duration, and context.

11. Caloric surplus and muscle glycogen

Adequate carbohydrate intake helps restore glycogen stores. For Strongman, this can support repeated sessions, training volume, and the ability to maintain intensity across consecutive days.

Stored glycogen connects endocrinology directly to performance: insulin supports storage, muscle contraction increases glucose uptake, and energy availability determines how easily this system can be maintained.

12. Energy surplus and recovery

More energy availability can support recovery by supplying substrates for glycogen restoration and tissue synthesis. It does not mean the body recovers instantly just because a surplus exists.

Sleep, load management, and sufficient protein remain essential. Endocrinology can support a recovery environment, but it cannot erase a poorly designed program.

13. When a surplus starts favoring fat gain

As the surplus becomes larger than what can be efficiently directed toward tissue synthesis and the costs of training, a greater proportion of the extra energy can end up in adipose stores.

There is no magical point where the body stops making muscle and starts making only fat. Both processes can occur at the same time, and their relative contribution depends on surplus size, training, metabolic status, and training experience.

14. Why a larger surplus does not mean more hypertrophy

Reviews of energy surplus during resistance training have not established a universally validated surplus that maximizes muscle gain while minimizing fat gain. Individualization is important.

This matters in Strongman: aggressively increasing body mass may improve performance in some contexts, but every additional kilogram does not have the same sporting value.

15. Appetite during a mass-gain phase

A controlled surplus can be difficult to maintain if the athlete has a low appetite. Food volume, energy density, and meal distribution then become practical considerations.

Appetite should not be pushed indefinitely. A surplus that causes constant nausea, digestive discomfort, and poorer sleep can impose a performance cost greater than its metabolic benefit.

16. Leptin, satiety, and overfeeding risk

Rising leptin alongside adipose mass can contribute to signaling that energy reserves are increasing. But higher leptin does not guarantee that appetite will be fully suppressed.

In chronic overfeeding, satiety and food-reward systems can become harder to manage than a single hormone measurement would suggest.

17. Cortisol during an energy surplus

Adequate energy intake can remove one physiological stressor represented by energy deficiency. Cortisol, however, is not determined by calories alone.

Heavy training, psychological stress, and insufficient sleep can maintain a stress response even when energy intake is high. “I eat enough” does not automatically mean “I recover perfectly.”

18. Surplus and connective tissues

Adequate energy availability supports tissue remodeling. Tendons, ligaments, and bone need energy and substrates for maintenance and adaptation.

But connective tissues do not adapt at the same rate as muscle. A surplus can support the infrastructure, but it does not eliminate the biological lag between tissues.

19. Body weight rises for several reasons

At the beginning of a surplus, scale weight can rise quickly because glycogen stores increase along with associated water, while gastrointestinal contents also change. This is not equivalent to new muscle or fat tissue.

For Strongman, this distinction is important when evaluating progress. A rapid early increase in body weight should not automatically be interpreted as accelerated hypertrophy.

20. Surplus and strength performance

More body mass, more glycogen, and good energy availability can support performance. The effect can be direct through fuel availability and indirect through greater ability to tolerate training volume.

Performance remains dependent on technique, coordination, relative strength, leverage, conditioning, and training specificity. Greater body weight is not guaranteed to mean greater strength.

21. Surplus and insulin sensitivity in Strongman

An active Strongman has metabolic advantages compared with a completely sedentary person because muscle mass and muscle contraction provide important routes for glucose disposal.

Body size itself, however, is not protection against metabolic dysfunction. If the surplus is very large and adipose tissue increases substantially, the benefits of physical activity can be outweighed by chronic energy excess.

22. What happens when the surplus becomes excessive

Chronic overfeeding can raise insulin and leptin and alter glucose and lipid metabolism. Over time, excessive fat gain can be associated with metabolic inflammation and reduced insulin sensitivity.

This is why a productive surplus and aggressive overfeeding are different phenomena. One aims to support adaptation. The other can create metabolic costs out of proportion to its performance benefit.

23. Why surplus should not be measured only on the scale

For a Strongman, useful indicators include strength progression, bar speed when available, ability to tolerate volume, circumferences, body composition, recovery, and sleep quality.

A mass gain accompanied by poor digestion, reduced mobility, higher blood pressure, or worse conditioning is not necessarily a good trade for performance.

24. Surplus and protein requirements

Protein supplies the amino acids required for protein synthesis. An energy surplus does not replace adequate protein intake or sensible distribution of protein across meals.

But a surplus does not make infinitely large protein doses infinitely anabolic. There are physiological limits to the rate at which tissues can use substrates for synthesis.

25. Surplus, carbohydrates, and performance

Carbohydrates are an important fuel source for repeated efforts and can support glycogen restoration. For Strongman, intake should be matched to training volume and demands rather than to an abstract fear of insulin.

Food-source choices matter for digestion, micronutrient intake, and tolerance, but the sporting goal remains adequate fuel without making the surplus so large that metabolic and gastrointestinal costs rise unnecessarily.

26. Surplus and water retention

Higher carbohydrate intake and glycogen storage can increase associated body water. Sodium and gastrointestinal volume also contribute to short-term scale changes.

Therefore, a rapid scale fluctuation cannot be translated directly into kilograms of newly created tissue.

27. Surplus and the nervous system

Good energy intake can reduce physiological stress associated with underfeeding and support brain and cognitive function. For a strength athlete, that may improve training tolerance and the ability to maintain concentration.

A very large surplus that produces sleepiness, digestive discomfort, and reduced activity can have the opposite effect.

28. The ideal surplus is not universal

What is enough for a novice may differ from what an advanced Strongman can use. Training experience, muscle mass, daily activity, genetics, appetite, and competition goals all change the response.

For this reason, the literature does not support a rigid formula claiming that one exact surplus is perfect for every athlete.

29. What to monitor in practice

A well-managed surplus aims for enough improvement in performance and lean mass while keeping the rate of fat gain tolerable. Trends matter more than a single measurement.

Weekly average body weight, circumferences, event performance, appetite, digestion, and sleep can collectively tell you much more than one hormone level.

30. When a surplus becomes a medical issue

Persistently abnormal glucose, HbA1c, blood pressure, insulin-resistance markers, or new symptoms warrant medical evaluation. A very large athlete should not automatically be assumed to be metabolically healthy.

At that point, the goal is no longer optimizing a “bulk,” but protecting health and adapting the plan with qualified professionals.

31. Conclusion: surplus is infrastructure, not magic

A caloric surplus creates a different energetic environment from restriction. Insulin and leptin tend to rise, ghrelin dynamics change, energy availability for tissue synthesis improves, and endocrine systems involved in energy and reproduction no longer receive the same signal of scarcity.

But the body does not automatically turn every calorie into muscle. A moderate surplus can support training and adaptation. An excessive surplus can increase fat storage and worsen metabolic health.

For Strongman, the goal is to build enough energetic infrastructure to grow and perform without turning the surplus into a race for the largest possible number on the scale. Hormones help. Training, energy, protein, carbohydrates, sleep, and body-weight management determine the final result.

Selected references

1. Slater GJ, Dieter BP, Marsh DJ, Helms ER, Shaw G, Iraki J. Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training? Frontiers in Nutrition. 2019;6:131. DOI: 10.3389/fnut.2019.00131.

2. Van Every WD, D'Souza AC, Phillips SM. Hormones, Hypertrophy, and Hype: An Evidence-Guided Primer on Endogenous Endocrine Influences on Exercise-Induced Muscle Hypertrophy. Exercise and Sport Sciences Reviews. 2024;52(4):117-125. DOI: 10.1249/JES.0000000000000346.

3. Kraemer WJ et al. Recovery responses of testosterone, growth hormone, and IGF-1 after resistance exercise. Journal of Applied Physiology. 2017. DOI: 10.1152/japplphysiol.00599.2016.

4. Hagobian TA, Sharoff CG, Braun B. Effects of short-term exercise and energy surplus on hormones related to regulation of energy balance. Metabolism. 2008;57(3):393-398. DOI: 10.1016/j.metabol.2007.10.016.

5. Gharahdaghi N et al. Links Between Testosterone, Oestrogen, and the Growth Hormone/Insulin-Like Growth Factor Axis and Resistance Exercise Muscle Adaptations. Frontiers in Physiology. 2021. DOI: 10.3389/fphys.2020.621226.

6. Contemporary literature on energy surplus, appetite regulation, insulin sensitivity, and endocrine adaptation in athletes.