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I am not particuarly wide, but I have a sort of pot belly that's gotten worse now that I've been at college for about a month. I'm about 5'1 and 120 pounds....I was about 116 a month ago. My main concern is not the actual numerical number but getting rid of my pot belly. I really never exercise rather than walking to class, and I know I should, but I am wondering what would be the best kind of exercise for me?

Should I do stretches? Last time I tried to do tummy flattenng exercises (from a magazine) I pulled a muscle or something and my tummy hurt for weeks. Would going on a long walk everyday help? Running? Perhaps an exercise bike? I don't want to waste my time doing something that's not going to help, as my time's limited. I want do something that doesn't take a lot of my time up but is effective. How often should I exercise?

And should I change my diet any? I eat healthy meals but tend to snack a lot on junk food.