Well, not usually. The source of calories has nothing to do with their ability to become body fat. Calories are, in truth, just units of energy. If you take in too many calories for your daily workload, that energy will probably be deposited on your body as flab fat. So, the source of the calories has little to do with body fat.
Fat calories are usually empty.
A donut, for example, has as many calories as a chicken breast. Each of these foods contributes calories, which are units of energy. And if either one gives you more calories than you need, those calories will become body fat. On the other hand, if you actually need this calorie level, body fat won't happen-the calories will be used to meet basic energy needs. If appetite doesn't happen and you slide into skinny, then add calories to your diet.