I used to be quite a lean fit guy. But recently, I've been putting on a few pounds. I realize I need to go on a diet because I feel like a sausage in my jeans. 

I begin to admire those guys who can always keep their figures. In order to be slim again, I made some plans for myself to keep fit.

First of all, go on a diet. Eat more nutritious food, kick off junk food. No potato chips, no popcorn, no candy bars.  Eat three meals a day, and try not to snack in between. Eat less of what I do eat.  Eat low-calorie food.

Secondly, go running three times a week at least. Go for a stroll after each meal. Any kinds of exercising can be helpful to burn more calories. 

Thirdly, follow these disciplines and stick to it as long as I can. Long-term self-discipline can make a difference.