How to gain weight is as difficult as losing weight. Okay, that might be a slight exaggeration; but we all know someone who is skinny as a stick and does not shy away from food. Most of us are envious that they never put on weight, but they too wish to have a lean well toned, even curvy or muscular look. How to gain weight: People may be underweight due to various reasons Inadequate feeding habits, prolonged meal time gaps, poor selection of foods, increased physical activity without increasing the food intake can lead to energy deficit, are a few of the major reasons for being underweight. Other reasons can be malabsorption due to prolonged illness, diseases such as tuberculosis, cancer, hormonal imbalances (hyperthyroidism) and eating disorders such as anorexia nervosa or bulimia. How to gain weight: Healthy weight gain Gradual weight gain is always advisable. An increase in 500 kcal per day can result in increasing the body weight by 0.5 kgs per week. Objective s...