Don't eat 3 square meals a day. It's not good for you metabolism.
Metabolism(noun): A chemical raction occuring withing every living organism to maintain life. 

Instead, eat about 5 to 6 times a day.How cool is that! The only thing is, only eat about 250-275 calories everytime you eat.

Although is really depends on how much calories you should consume in a day. Take that number, then divide it by the number of times your planning on eating and now yoy have the number of calories per "meal."

So, maybe next time reach for an apple instead of the doughnut.