Dear Li Jin,
(A1 following-up) Lately, I found that you're suffering from a bad eating habit, such as being picky about food, skipping breakfast, and loving to eat fast food. (A2 purpose) Concerned about you, I'm writing to remind you of the side effect of those and give you some suggestions.
(B1 disadvantage of unbalanced diets) As we know, being a picky eater may lose balance of health while a preference to oily food will keep you overweight. Besides, you'll starve if you don't take breakfast.
(B2 suggestions) In this case, first, I greatly advise you to keep away from junk food and keep balanced diets, which helps you build up a strong body. In addition, you'd better have meals on schedule so that you'll stay energetic all day long.
(C2 expectation) I wish you luck.
Yours,
Li Hua
