Regardless of your present body weight the important knowledge about proper nutrition is to eat a balanced meal.
By that it mean proper proportion of protein to build muscle, carbohydrates to supply energy to do work and
vitamins and minerals the body needs to produce enzymes and hormones to maintain bodily health/life.
Try to eat a variety of vegetables as each contain various vitamins and minerals.Spinach is good ( contains many
nutrients.So are califlower,brocolli,carrots ( vitamin A for eye).In TCM traditional chinese medicine, a balance
diet also means foods that have the various tastes like sweet,sour,salty and bitter in order for health.Modern
fast foods are salty and sweet but where are the rest? Proper rest and sleep are important too.
If you have the discipline to learn photography then learning to eat properly should not be a problem.