Aging does play a role too. As you age, you lose muscle — especially if you're not physically active. Loss of muscle mass decreases the rate at which your body uses calories, which can make it more challenging to maintain a healthy weight. According to the 2015-2020 Dietary Guidelines for Americans, men in their 50s need about 200 fewer calories daily than they do in their 30s due to this muscle loss.
A waist size greater than 40 inches indicates a man is at a high risk of type-2 diabetes and heart disease. This inflated, firm belly is due to an overabundance of visceral fat, which lies deep inside your trunk nestled around internal organs. Visceral fat -- unlike the subcutaneous fat that resides just under the skin on the abdomen, hips, thighs and arms -- secretes hormones and compounds that raise inflammation, which contributes to heart disease. Men are genetically more likely to store fat in their gut, rather than the lower body, and certain lifestyle habits exacerbate weight accumulation in the middle.
First one’s the Adrenal belly or Adrenal shape, caused by increased levels of cortisol. When going through stressful periods, the production of cortisol increases, and this favours the accumulation of fat around the waist, leading to a saggy abdomen. Both men and women are likely to gain weight around the waist if they are constantly exposed to high levels of stress, and besides the excess belly fat, they are also likely to experience fatigue, back pain, nervousness, poor memory and sleep problems.