Belly Fat and Hormones: What’s Really Going On Inside Your Body + Action plan
Belly fat—especially the deep kind that surrounds your organs, called visceral fat—isn’t just about looks. It’s an active tissue that releases chemicals and hormones, increasing risks of type 2 diabetes, heart disease, and inflammation (Hu et al., 2025).
So, what drives belly fat? The answer lies in hormones, thyroid health, and lifestyle factors.
Why Belly Fat Matters
Unlike fat stored under the skin (subcutaneous fat), visceral fat produces inflammatory molecules that worsen blood sugar control and raise blood pressure. Even people with a “normal” body weight can face higher disease risks if visceral fat is high (Hu et al., 2025).
The Hormones Behind Belly Fat
Cortisol: The Stress Hormone
When stress is ongoing, cortisol stays elevated. This promotes fat storage around the belly. Research shows that functional hypercortisolism (chronically high but not disease-level cortisol) can drive visceral fat gain and insulin resistance by disrupting the HPA axis (Insulin and the HPA Axis, 2023; Walker, 2024).
Insulin: The Blood Sugar Hormone
Insulin resistance—when cells no longer respond effectively to insulin—causes sugar to remain in the bloodstream, pushing the body to store fat, especially in the abdomen. A large 2024 study confirmed strong links between abdominal fat measures and insulin resistance (Shi et al., 2024).
Thyroid Hormones: Your Metabolism Regulators
Thyroid hormones set your metabolic pace. New studies show that even in people with “normal” thyroid results, reduced sensitivity to these hormones is associated with more visceral fat. This is true for both type 2 diabetes patients (Lu et al., 2024) and euthyroid adults (Wei et al., 2024)
Sex Hormones and Belly Fat
Oestrogen: Menopause and the Belly Fat Shift
Oestrogen helps women store fat in hips and thighs. When levels fall during menopause, fat storage shifts to the belly.
A Journal of Clinical Endocrinology & Metabolism study (2020) found that oestrogen therapy reduced visceral fat while increasing subcutaneous fat in transgender women, showing oestrogen’s protective role (Klaver et al., 2020).
Reviews confirm that oestrogen influences enzymes like lipoprotein lipase and boosts insulin sensitivity, both of which regulate where fat is stored (Davis et al., 2024).
Testosterone and Belly Fat in Men
In men, testosterone helps maintain muscle and prevent fat buildup. But as testosterone drops with age, belly fat often rises. Worse, belly fat itself can lower testosterone further because it contains an enzyme (aromatase) that converts testosterone into oestrogen, creating a vicious cycle (Grossmann, 2024).
What about new weight-loss drugs?
A recent ENDO 2025 study followed obese men taking GLP-1 medications (like semaglutide and tirzepatide). On average, they lost about 10% of their body weight, and testosterone levels increased by ~18%. The proportion of men with healthy testosterone rose from 53% to 77% (Portillo-Canales et al., 2025; Reuters, 2025).
But were the results caused by the drug or the weight loss?
Current evidence suggests the rise in testosterone is primarily due to weight loss. Losing fat reduces aromatase activity (so less testosterone is converted to oestrogen) and improves insulin sensitivity, both of which support healthier testosterone levels.
Researchers are exploring whether GLP-1 drugs also have direct effects on hormone pathways, such as boosting luteinizing hormone (which stimulates testosterone production). But so far, the main driver of testosterone improvement seems to be the fat loss itself (Mens Reproductive Health, 2025; MaleReady, 2025).
So lets Recap and See What's Happening Inside Your Body
Stress → cortisol rises → belly fat builds.
Poor insulin sensitivity → more abdominal fat storage.
Thyroid hormone sensitivity drops → metabolism slows.
Estrogen decline → fat shifts from hips/thighs to belly.
Low testosterone → less muscle ( sarcopenia ), more belly fat.
Visceral fat itself worsens hormone balance → creating a vicious cycle.
Can Protein and Resistance Training Help Reduce Belly Fat
Belly fat becomes harder to lose as we age. After 50 and as we know, hormonal shifts, slower metabolism, and muscle loss make it easier to store fat—especially around the midsection. But the good news is, science shows that two powerful strategies can fight belly fat at any age: eating enough protein and doing resistance training.
Higher Protein = Less Belly Fat
Research shows that getting more protein can help reduce visceral belly fat. In one clinical trial, older men who increased their protein intake to 1.3 g per kg of body weight per day lost a significant amount of visceral fat compared to men who ate the standard 0.8 g/kg/day (Kim et al., 2020).
A meta-analysis of adults over 50 also found that higher-protein diets helped people lose more fat and preserve lean muscle while dieting (Kim et al., 2020b).
Most people over 50 do better aiming for 25–30g of protein per meal (e.g., eggs + Greek yogurt at breakfast, chicken or fish at lunch, beans or tofu at dinner).
Resistance Training = Stronger Muscles, Less Belly Fat
Cardio is great for heart health, but resistance training (weight lifting, bodyweight, bands) is especially powerful against belly fat after 50.
In a study of postmenopausal women, just 15 weeks of resistance training led to a clear reduction in abdominal fat (Maturitas, 2023).
Another study in older adults with obesity found the best results came from combining resistance training + cardio + diet. This combo led to the largest drops in belly fat and the best improvements in health markers (Villareal et al., 2022).
You don’t need a gym. Squats, push-ups, lunges, and resistance bands at home all count.
Why the Combo Works Best
Protein fuels muscle growth and protects lean mass.
Resistance training builds and preserves muscle.
Together, they increase metabolism and specifically target visceral fat.
This means you’re not just losing weight—you’re reshaping your body, improving health, and reducing risks linked to belly fat (like diabetes and heart disease).
Action Plan for Over 50
Eat more protein (1.2–1.3 g/kg/day if possible) Please consult your Doctor before increasing protein to your diet as it is not suitable for everyone.
Click here for my protein blog
Move More: Combine cardio + resistance training for best visceral fat reduction (Georgetown Journal of Gerontology, 2024).
Click here for my resistance training blog
Eat Smarter: High-fiber, whole-food diets improve insulin sensitivity (Shi et al., 2024). Add sufficient amounts of quality protein.
Click here for my insulin resistance blog
Manage Stress: Stress-reduction helps regulate cortisol (Walker, 2024).
Sleep Better: Restores appetite hormones (ghrelin, leptin).
Check Hormones:
Women: Look into HRT or alternative options and discuss with your GP (Davis et al., 2024).
Men: Test testosterone if energy is low or belly fat rises (Grossmann, 2024).
Everyone: Check thyroid function if unexplained belly fat persists.
Disclaimer: This blog post is for informational and educational purposes only and is not intended as medical advice. Always consult your doctor or qualified health professional before making changes to your diet, exercise, or health routines.
References
Davis, S. R., Lambrinoudaki, I., Lumsden, M. A., Mishra, G. D., Pal, L., Rees, M., & Santoro, N. (2024). Menopause, hormones, and belly fat: Mechanisms and management. Frontiers in Endocrinology, 15, 1427812.
Grossmann, M. (2024). Testosterone and metabolic health in men: Causes and consequences of low testosterone. Nature Reviews Endocrinology, 20(3), 143–158.
Hu, M. J., Stampfer, M. J., & Shai, I. (2025). Visceral adipose tissue area and proportion provide distinct insights into cardiometabolic risk. BMC Medicine, 23, 57.
Insulin and the HPA-Axis in the Metabolic Syndrome. (2023). Encyclopedia of Endocrinology, 1–12.
Kim, J. E., O’Connor, L. E., Sands, L. P., Slebodnik, M. B., & Campbell, W. W. (2020a). Effects of dietary protein intake on visceral fat in older men: The OPTIMen trial. Journal of Gerontology: Medical Sciences, 76(6), 1084–1091. https://doi.org/10.1093/gerona/glaa012
Kim, J. E., et al. (2020b). Effects of dietary protein intake on body composition changes after weight loss in older adults: A systematic review and meta-analysis. Nutrition Reviews, 74(3), 210–224. https://pmc.ncbi.nlm.nih.gov/articles/PMC4892287/
Klaver, M., et al. (2020). Effects of gender-affirming hormone therapy on body fat distribution. Journal of Clinical Endocrinology & Metabolism, 105(3), 895–904.
Lu, Y., Liu, Y., Wang, Y., et al. (2024). Increased thyroid hormone sensitivity is correlated with visceral obesity in type 2 diabetic patients. Lipids in Health and Disease, 23, 337.
Maturitas (2023). Whole-body resistance training decreases abdominal adiposity in postmenopausal women. Maturitas, 171, 1–8. https://www.maturitas.org/article/S0378-5122%2823%2900400-0/fulltext
Mens Reproductive Health. (2025). GLP-1 agonists in men: Effects on testosterone, sperm, and sexual function. Journal of Men’s Health Reviews.
Portillo-Canales, R., et al. (2025). GLP-1 agonists improve testosterone and body composition in obese men. Presented at ENDO 2025 Annual Meeting.
Reuters. (2025, July 16). GLP-1 obesity drugs may boost low testosterone in men. Reuters Health News.
Shi, J., Chen, J., Zhang, Z., & Qian, G. (2024). Abdominal obesity indices and insulin resistance in assessing NAFLD risk. BMC Public Health, 24, 2161.
Villareal, D. T., Aguirre, L., Gurney, A. B., Waters, D. L., Sinacore, D. R., Colombo, E., Armamento-Villareal, R., & Shah, K. (2022). Effect of aerobic or resistance exercise, or both, on visceral and intermuscular fat and metabolic function in older adults with obesity. Journal of Gerontology: Series A, 77(1), 131–140. https://doi.org/10.1093/gerona/glab081
Walker, B. R. (2024). Cortisol and metabolic syndrome revisited: Mechanisms and clinical insights. Endocrine Reviews, 45(2), 251–270.
Wei, Y., Yang, M., Liu, J., et al. (2024). Associations between sensitivity to thyroid hormones and visceral adiposity in euthyroid adults. Journal of Clinical Endocrinology & Metabolism, 110(8), e2744–e2753.