Brief Answer:
Eat high calories food

Detailed Answer:

Hello,

I think you may need to choose better the type of food you eat. You may prefer carbohydrates as the base of your meals using pasta, rice, bread, potatoes or other starchy carbohydrates.
You can also add protein in your plate such eggs, red meat, fish, beans etc.

Also choose plain yoghurt, milk and cheese. You can also eat plenty of fruit and vegetables especially bananas, grapes, figs etc. Eat at least five times per day.

Hope I have answered the question. Let me know if I can assist you further.

Regards

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