Sudden loss of weight should be examined and you should undergo investigations such as serology tests,
thyroid profile, etc. You must rule out all possible underlying factors. Weight can be gained by eating excessive junk food or any kind of food more than the calories you burn but this is not a healthy increase in weight. Healthy weight can be attained by the following steps:
- Don't skip meals, you may not feel like eating but in such conditions you should have the reduced amount in frequent intervals(i.e. 3 square meals broken down to 5 or 6 as you can tolerate) and slowly increase as you get better.
- Reduce/ Avoid spicy,fried, fatty, junk and oily food
- Exercise regularly (minimum 30-45mins per day)
- Increase daily intake of water to 3 liters
- Avoid/Stop smoking and drinking if you have the habit
- Reduce stress through methods such as yoga/meditation.