Calculate your BMI and if you are lower than the lowest permissible for your weight and height you can start taking more
protein in you
diet. You can start the day in place of coffee with milk and
protein supplements. Can have more eggs for breakfas. Increase the meat in your diet, soya, cheese, tofu, sprouts etc. Gaining weight by healthy food habits is recommended rather than deep fries, sweets, cholesterol, etc. Take care!