Just like overweight people are worried about losing weight, similarly, underweight people are worried about gaining weight. According to WHO, 462 million adults in the whole world are underweight. This causes many serious health problems and can lead to complications in the long run. The main question everyone asks is, How to gain weight naturally? Losing weight is a little easy, as you start dieting and workout. But gaining weight naturally and without any equipment gets little tuff. As y...