Part of the explanation may lie in where fat can accumulate.
There are different kinds of body fat. Subcutaneous fat, the fat that you can pinch under your skin, is metabolically benign. You may not like the way it looks but it does not appear to significantly increase your risk for the health problems we typically associate with obesity.
On the other hand, visceral fat, the fat found inside the abdomen and chest around the internal organs, is very metabolically active. Visceral fat produces substances that promote inflammation, raises blood pressure and triglycerides, lower HDL levels, change hormone levels and interfere with control of blood sugar.
Measuring your weight or your BMI does not tell you whether your fat is subcutaneous or visceral fat. The only accurate way to measure visceral fat is with a CT or MRI scan.
Visceral fat appears to result from a genetic predisposition combined with a high carbohydrate diet and a sedentary lifestyle. The more you exercise, the less likely you are to have visceral fat. Fit overweight people are more likely to carry their extra weight as the much less harmful subcutaneous fat.
Many of us are frustrated with constant diets and trying to lose weight that just won’t stay off. While it may not get you back into the clothes you wore when you were 20, focusing on getting at least 150 minutes per week of exercise may help you to avoid many of the health problems that can come with being overweight. Even if you don’t lose weight, staying active will be an excellent investment in the quality of your future years.