Yes you need to put on some weight and for this focus on diet
,exercise, water and sleeping pattern.
Eat low fat low carb, high protein, high fibre diet devided inyo 3 main and 3 small meals.
Do you have gastric trouble for all tge day or only in evening please tell,and also share your present eating pattern to assess your problem and guide you accordingly
Next Steps
Eat light roasted or steamed snacks only in evening time
Health Tips
Eat healthy keep healthy