AIIMS, Harvard, Stanford-trained gastroenterologist explains why belly fat increases after 30; shares tips to lose it

By Admin

22 Dec, 2025

Losing stubborn belly fat is a common fitness goal, especially as people enter their thirties. Many find that despite eating the same foods and following similar workout routines, fat around the abdomen begins to increase. According to Dr Saurabh Sethi, a California-based gastroenterologist trained at AIIMS, Harvard, and Stanford Universities, this change is not random but driven by natural physiological shifts in the body after the age of 30.

In an Instagram post dated 21 December, Dr Sethi explained that metabolism slows with age, leading to increased fat storage even without major lifestyle changes. “The same foods lead to more belly fat. The same workouts give fewer results,” he noted, adding that even occasional cheat meals have a much bigger impact than before.

Why Belly Fat Increases After 30

Loss of muscle mass
Dr Sethi highlighted that adults naturally lose around 3–8 percent of muscle mass per decade after turning 30. Since muscle tissue burns more calories than fat, this loss significantly reduces the body’s resting energy expenditure. Muscles also play a critical role in glucose disposal, handling nearly 70–80 percent of it. When muscle mass declines, glucose remains in the bloodstream longer and is more likely to be stored as abdominal fat.

Declining insulin sensitivity
As people age, insulin sensitivity decreases by approximately 4–5 percent per decade. This means the same carbohydrate intake causes higher blood sugar spikes, leading to quicker fat storage, particularly around the waistline.

Hormonal changes
Hormonal shifts after 30 also contribute to belly fat accumulation. Levels of human growth hormone, testosterone, and oestrogen decline, while cortisol levels rise. According to Dr Sethi, this hormonal combination promotes deep abdominal or visceral fat storage.

As these factors combine, visceral fat accumulates more rapidly than subcutaneous fat. This deep belly fat surrounds internal organs and increases inflammation and insulin resistance. The impact is even stronger in individuals with fatty liver disease, prediabetes, diabetes, or high triglycerides, as insulin resistance pushes more fat into the abdomen and liver.

Signs Your Metabolism Is Slowing

Dr Sethi also listed common signs that may indicate a slowing metabolism, including an increase in belly size despite stable body weight, afternoon energy crashes, stronger sugar cravings, bloating after consuming carbohydrates, and fat gain in the upper abdominal region.

Tips to Reduce Belly Fat After 30

To counter these age-related changes, Dr Sethi shared practical lifestyle tips. He recommends consuming sufficient protein, ideally 1.2 to 1.6 grams per kilogram of body weight daily, to support muscle mass. Strength training should be done at least three times a week to preserve and build muscle. Daily walking can help improve insulin sensitivity, while prioritising 7–8 hours of quality sleep is essential for hormonal balance and fat regulation.

Conclusion

Belly fat gain after 30 is largely driven by natural changes in muscle mass, insulin sensitivity, and hormone levels. While these shifts are unavoidable, adopting the right nutrition, exercise, and sleep habits can significantly slow fat accumulation and improve overall metabolic health.

Note to readers: This article is for informational purposes only and is not a substitute for professional medical advice. Always consult your doctor for guidance related to medical conditions.

This report is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.