Strongman Physiology - Episode 8: Insulin and the Metabolism of the Strength Athlete

1. Insulin is not simply the “sugar hormone”

In fitness culture, insulin is often reduced to the idea that it is the hormone that moves sugar into muscle. That is only a starting point. Insulin coordinates energy distribution and storage and influences carbohydrate, lipid and protein metabolism. For a strength athlete, this matters because performance depends on repeatedly receiving, storing, mobilizing and using fuel.

2. Where is insulin produced?

Insulin is produced by pancreatic beta cells. Secretion is driven mainly by rising glucose, but amino acids, incretins and autonomic signals also shape the response. After a meal, the pancreas responds as part of an integrated metabolic system.

3. The insulin receptor and cellular signaling

Insulin acts through the insulin receptor, a receptor tyrosine kinase. Signaling involves IRS, PI3K and AKT. In skeletal muscle, a major outcome is GLUT4 translocation to the membrane and increased glucose uptake.

4. GLUT4 and skeletal muscle

GLUT4 is a major glucose transporter. Insulin and muscle contraction promote GLUT4 movement to the cell surface. This helps explain why active muscle handles glucose efficiently and why exercise can improve insulin sensitivity.

5. Insulin and glycogen

Insulin promotes muscle glycogen synthesis. Glycogen is the muscle's local carbohydrate reserve and becomes important during repeated sets, carries, loading events and medleys. After exercise, increased insulin sensitivity helps restore these stores.

6. Muscle contraction increases insulin sensitivity

Exercise activates glucose-transport pathways that are partly independent of insulin and can improve subsequent insulin responsiveness. Trained muscle is therefore a major metabolic compartment.

7. Insulin sensitivity versus insulin resistance

Insulin sensitivity describes how strongly tissue responds to insulin. Insulin resistance means the response is reduced or a larger signal is required for the same effect. A single glucose reading cannot describe the entire phenomenon.

8. Muscle mass and metabolic health

A heavily muscled Strongman has a large compartment for glucose uptake and glycogen storage. Muscle mass does not automatically protect against metabolic problems. Visceral adiposity, sleep, diet, activity outside the gym and genetics remain important.

9. Insulin and the liver

Insulin suppresses hepatic glucose production and supports storage and nutrient use in the fed state. An athlete's metabolism cannot be understood from muscle alone.

10. Insulin and adipose tissue

In adipose tissue, insulin suppresses lipolysis and supports energy storage. This is normal physiology. Problems arise when chronic energy excess, inflammation and insulin resistance dominate the metabolic environment.

11. Insulin and protein metabolism

Insulin has an anti-catabolic role in muscle by reducing protein breakdown. With sufficient amino acids, its direct effect on protein synthesis is more modest than the myth that insulin alone builds muscle suggests.

12. Insulin, leucine and mTOR

Insulin signaling can intersect with AKT-mTOR, but mTOR also receives information from amino acids, mechanical loading and energy status. Hypertrophy comes from integration of these signals, not from maximizing insulin.

13. Carbohydrates are not insulin's enemy

Carbohydrates normally raise glucose and insulin. For Strongman, they are often useful for glycogen restoration and repeated efforts. The relevant question is how much, when and in what context they are needed.

14. Why the post-workout meal is physiological

A meal containing protein and carbohydrate after training stimulates insulin as part of the normal response to food. The insulin rise is not inherently harmful and should not become an absolute anabolic target.

15. Glycogen and Strongman events

A maximal deadlift relies heavily on rapid energy systems and neural output. Medleys, carries and longer efforts increase the importance of glycogen and glycolysis. Carbohydrate restoration between sessions can therefore matter greatly.

16. Insulin is not the same thing as energy balance

Insulin regulates metabolic flux but does not erase long-term energy balance. The same foods can appear in a deficit, maintenance diet or surplus depending on total intake and requirements.

17. Insulin and fasting

During fasting, insulin falls and fuel mobilization increases. For a Strongman, very long fasts can make adequate energy and protein intake harder to achieve, especially during high-volume periods.

18. Insulin after exercise

Exercise increases insulin sensitivity, allowing muscle to take up glucose efficiently after the session. This is one mechanism through which regular training supports metabolic health.

19. Insulin and very high body mass

In the open class, a Strongman can carry very high body mass with different combinations of muscle and adipose tissue. High body weight does not automatically mean poor metabolic health, but neither does it guarantee metabolic health.

20. Why visceral fat matters

Visceral adipose tissue is associated with low-grade inflammation, insulin resistance and greater lipid flux to the liver. Two Strongmen at the same weight can therefore have very different metabolic profiles.

21. Insulin and recovery

Insulin participates in the fed state of nutrient storage and use, but recovery is much broader: glycogen, amino acids, hydration, sleep and training-load management.

22. Insulin and sleep

Sleep influences glucose control and insulin sensitivity. Sleep restriction can impair metabolic responses and can change appetite and perceived effort.

23. Catecholamines and counter-regulation

Adrenaline and noradrenaline rise around intense effort and can increase glucose availability. During competition, these signals can temporarily counterbalance insulin's storage actions.

24. Glucagon and fuel mobilization

Glucagon contributes to maintaining blood glucose and mobilizing fuel during fasting. Athletic metabolism continuously shifts between storage and mobilization.

25. The anabolic window needs nuance

There is no few-minute window in which progress is lost because insulin does not rise immediately. Total daily intake and realistic meal distribution are more important than obsessive timing.

26. Insulin and competition nutrition

Competition nutrition must account for event duration, intervals and gastrointestinal tolerance. Carbohydrates can be useful, and the insulin response is normal physiology rather than a magic protocol.

27. Insulin resistance does not mean the body cannot use carbohydrates

Insulin resistance is a complex change in metabolic signaling. It is not synonymous with absolute carbohydrate intolerance and cannot be diagnosed from how someone feels after a meal.

28. Why resistance training has metabolic value

Resistance training preserves muscle mass, increases glucose use and can improve insulin sensitivity. Muscle is a major metabolic organ, not just a force-production system.

29. Light activity between training sessions

Walking and low-intensity physical activity can increase glucose use without the recovery cost of another hard session. For a large athlete, this can be a simple tool for metabolic health.

30. Low-carb is not a universal rule

Reducing carbohydrates can fit selected phases, but Strongman includes many events where glycogen availability matters. The goal is appropriate fuel, not minimum insulin.

31. Fiber, fat and glucose dynamics

Fiber, fat and protein can change gastric emptying and post-meal glucose dynamics. A real meal should be assessed as a whole rather than by carbohydrate grams alone.

32. Gastrointestinal tolerance in Strongman

A nutrition strategy can be metabolically sound and still fail if it causes nausea or bloating. Food tolerance should be tested in training, especially before multi-event competitions.

33. Insulin and hydration

Hydration and electrolytes affect muscle function, plasma volume and exercise tolerance. Metabolism cannot be optimized independently of hydration.

34. Glucose and the brain

The brain depends on stable energy availability, and the body tightly regulates blood glucose. During intense exercise, counter-regulatory hormones help maintain glucose availability.

35. Hypoglycemia and symptoms during competition

Weakness, shaking or dizziness do not automatically mean hypoglycemia. Dehydration, heat, catecholamines, fatigue and inadequate food intake can produce similar symptoms.

36. The medley as a metabolic model

A medley combines high muscular recruitment, short recovery and metabolite accumulation. Phosphocreatine, glycogen, glycolysis and oxidative metabolism all contribute.

37. Why post-competition metabolic recovery is different

After hours of effort, appetite, digestion and metabolic responses can temporarily change. Post-competition feeding should be effective but gastrointestinally tolerable.

38. Insulin and training adaptation

Repeated training changes substrate use and glycogen storage capacity. The athlete becomes more efficient at handling nutrients.

39. When training volume exceeds recovery

When total stress becomes excessive, sleep, appetite, energy and metabolic control can be affected. The solution is to correct the underlying problem rather than obsess over insulin.

40. Insulin and fat burning

Insulin suppresses lipolysis in the fed state, but body composition should be assessed over days and weeks. There is no need to avoid every insulin rise to lose fat.

41. Glycemic index is not the whole story

Glycemic index does not fully describe a real meal. Portion size, fiber, protein, fat and food combination all change the metabolic response.

42. Liquid carbohydrates

Carbohydrate drinks can be useful when solid food is difficult to tolerate. They are also easy to overconsume on sedentary days.

43. Insulin and body mass

An energy surplus can support muscle gain, but excessive surplus also increases fat storage. Heavier does not automatically mean better.

44. Metabolic flexibility

An efficient metabolism shifts between nutrient storage after meals and fuel mobilization between meals and during exercise. Flexibility is more useful than permanently low insulin.

45. Insulin and AMPK

AMPK acts as an energy sensor and becomes important when energy availability is reduced. During exercise it supports processes that produce and conserve energy.

46. Metabolic inflammation

Insulin resistance can be associated with low-grade inflammation and altered lipid flux. Regular physical activity and reduction of excess adiposity can improve the metabolic environment.

47. Insulin and testosterone

Energy metabolism and gonadal function are interconnected. Obesity, insulin resistance and low energy availability can influence androgen status.

48. Insulin and GH

The GH–IGF-1 axis is sensitive to energy status, and insulin, nutrition and growth hormone intersect at metabolic and hepatic levels.

49. Monitoring metabolic health

Depending on context, a clinician may monitor fasting glucose, HbA1c, lipids, blood pressure, liver function and other markers. No single marker describes the entire metabolism.

50. Conclusion: insulin is metabolic infrastructure

Insulin helps manage glucose, restore glycogen, reduce protein breakdown and coordinate the fed state. It is neither a hormone to suppress at all costs nor a magic button for hypertrophy.

For a Strongman, the lesson is simple: metabolic health should support performance rather than be sacrificed to a single marker. A well-regulated organism knows when to store, when to mobilize and how to return to balance.

Selected bibliography

1. Saltiel AR, Kahn CR. Insulin signalling and the regulation of glucose and lipid metabolism. Nature. 2001;414:799-806.

2. Sylow L, Kleinert M, Richter EA, Jensen TE. Exercise-stimulated glucose uptake - regulation and implications for glycaemic control. Nature Reviews Endocrinology. 2017;13:133-148.

3. Jørgensen SB, Richter EA, Wojtaszewski JFP. Role of AMPK in skeletal muscle metabolic regulation and exercise adaptation.

4. Thomas DT, Erdman KA, Burke LM. Nutrition and Athletic Performance. Position statement of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine.

5. American Diabetes Association. Standards of Care in Diabetes. Clinical guidance on glycemia, obesity and metabolic health.

6. IOC consensus literature on carbohydrate availability, athlete performance, recovery and training adaptation.

Editorial note: this article is educational and does not replace medical evaluation. Suspected diabetes, insulin resistance or other metabolic disorders require appropriate clinical assessment.