- Belly fat increases after age 30 despite unchanged diet or exercise habits
- Muscle loss of 3-8% per decade lowers metabolism and calorie burn at rest
- Reduced muscle mass impairs glucose disposal, increasing abdominal fat storage
Stubborn belly fat is something many struggle with. Changing your diet or hitting the gym hard doesn't always seem to help. Dr Saurabh Sethi, a board-certified gastroenterologist and hepatologist from Fremont, California, sheds light on the reasons behind it. In a series of Instagram posts with visuals, he points out that many people start noticing noticeable changes after turning 30.
He asks, “Are you noticing more belly fat even though your habits haven't changed? Want to reduce belly fat and improve digestion?”
The changes in the body after hitting 30 are:
Weight gain: The same foods lead to more belly fat
Reduced workout effectiveness: The same workouts give fewer results
Noticeable changes: Small "cheat days" cause noticeable gain
The doctor says, “This isn't random,” suggesting that the changes point to the underlying causes.
What Leads To Belly Fat
He further discusses the natural process of muscle loss, which occurs at a rate of 3-8% per decade after age 30, and its effect on metabolism. According to Dr Sethi, reduced muscle mass leads to lower calorie burn at rest. He mentions, “Even losing 1 kg of muscle reduces daily energy burn.”
The gastroenterologist explains the significant role of muscle mass in glucose storage and fat storage. According to Dr Sethi, muscle accounts for almost 70-80% of the body's glucose disposal. “When muscle mass drops, glucose stays in the blood longer and is more likely stored as abdominal fat,” he shares.
He says, “Insulin sensitivity declines by almost 4-5% per decade,” which means the same carbohydrates result in bigger sugar spikes, which in turn lead to faster fat storage, especially at the waist.
According to him, hormones shift after the age of 30. While growth hormone and sex hormones like testosterone or estrogen decrease, the cortisol level increases - a combination which favours deep abdominal fat storage. What is the result?
He explains, “Visceral fat (deep belly fat) accumulates faster than subcutaneous fat. This fat surrounds organs and worsens insulin resistance and inflammation.” He says, this hits harder if you have Fatty liver, Prediabetes or diabetes, and high triglycerides, because “insulin resistance pushes more fat into the abdomen and liver”.
What Are The Early Signs That Metabolism Is Slowing
According to Dr Sethi-
- The belly grows even if the weight is stable
- Afternoon energy crashes
- Stronger sugar cravings
- Bloating after carbs
- Fat gain in the upper abdomen
What Is The Solution
The doctor reveals that a proper diet, alongside a few other factors, leads to a reduction in belly fat. These are:
- Protein intake should be almost 1.2-1.6 g per kg daily
- Strength training more than 3 times per week
- Daily walking to improve insulin sensitivity
- Consistent 7-8 hours of sleep
- No extremes.
- No gimmicks.
In conclusion, dealing with belly fat requires proper planning and consistent lifestyle habits.