What is LMB???? As long as you follow the instructions you should be fine......If you still nervous use less than recommended and see how everything reacts.
No I don't think you'll starve him.....I run RowaPhos and it's well know it'll cause bleaching and such, and I just use half the recommended dosage and went from there.....Always better to be safe than sorry.
no he shouldn't starve...your lmb should be eating other food in the tank when you feed your others....they usually prefer the dusting of algae you see on the glass.....(sometimes you'll see kiss marks on the glass)....use the phosban