When you say your digestion is weak, that itself warranties a detailed inspection of your condition and management of your Agni or digestive fire. Only after that would your absorption improve and whatever healthy food that you're eating be beneficial to your body.
Try taking 5 grams of Ashtachoornam before lunch everyday with Buttermilk or warm water. It's a good start. See how your system is behaving and let's move forward from there.
Next Steps
Improve digestion and absorption
Health Tips
avoid proteins until your Agni is better as it's difficult to digest for the body.