India, Feb. 20 -- People who try to eat healthy, either to lose or gain weight, or stay in shape, often face unique challenges depending on what they are their goal is.

An individual who is on the heavier side and wishes to cut may find himself unable to lose weight easily despite eating less. At the same time, the person on the slimmer end of the scale who is trying to bulk often discovers that no matter how much he eats, hardly anything gets added to their frame.

Taking to Instagram on February 20, Dr Saurabh Sethi, California-based gastroenterologist trained in AIIMS, Harvard, and Stanford Universities, explained the science behind this phenomenon.

According to Dr Sethi, the loss or gain of weight because of the diet is influenced b...