it depends upon your height and genetics....to stay fit and to increase weight fallow this Avoid junk foods,add extra calories to your diet,have 4 to 5 meals rather than large 3...since you are diabetic avoid carbohydrates add protein rich foods and healthy fats to diet for e.g..egg white...add fibre rich foods like green leafy veggies,carrots,Apple, etc. Add green tea to your diet .you have to eat more foods high in amino acids,calcium, zinc, iron, copper and magnesium...do regular exercise without failure......consult dietitian for further details