Thanks for query.
Do not rely upon all these ads.
Main thing is to go for high protein nourishing diet.
Take plenty of milk, pulses, cereals, eggs, butter, ghee, puddings, dry fruits.
Take green veggies and fresh fruits.
Take moderate amount of fat and carbohydrates.
You may go for some multivitamin
If you got poor appetite
then you may take tablet Ciplactin
for some time.
You can have protein supplement like Protinules or provitex etc.
If you take this nourishing diet you may get increasing weight few kg.
Ok and bye.