This is a question that I ask myself a lot.  Too fat would mean that you are over your recommended body weight on any healthy weight chart, by about 10-12 pounds or more.   At the doctor, or even online, you can see the weight chart for your height, and bone structure.  A healthy weight gives you five or ten pounds extra that your frame could carry easily, and yet you would be healthy.  These charts are updated regularly, so don’t tell yourself that the new, ULTRA THIN ,is the good look, and the charts are outdated and incorrect.   In reality, where we all should be living, too thin is a big risk factor for all kinds of health problems.  Of course, being to fat has long term risks too.  How do your clothes fit?  Do you feel good about how you look?  What I do is try to exercise three or four times a week.  It does not have to be high impact exercise, you can walk, bike, dance, skate, play racket ball, or anything else that makes you move.  If you are overweight, the pounds will come off, slowly and they will stay off.  If you are the correct weight, and eat small portions of healthy food, you will look great and feel terrific.