It may be uncomfortable to exercise immediately after you've eaten, but it's not going to do you any damage. Contrary to popular belief, even swimming after you've eaten is fine.

It is true that exercise after a large meal may interfere with digestion as energy is directed away from the digestion process and towards the exercise; this can result in a slight stomach ache. However, all this really means is that if you run a marathon after Thanksgiving dinner you may make yourself ill. A comfortably-paced walk after the meal would be a better option and might help to relieve some of that bloated feeling.

Bottom line: You can exercise after you eat, but don't overdo it.

(Warning! If you do experience extreme tiredness or discomfort while exercising after eating after a meal, notify your doctor as it may be a symptom of undiagnosed hypertenstion.)

Lose weight? Yes. Effectively? No. When too few calories are consumed your body believes it is being starved and almost every calorie you consume is held on to. When this is the case, your body will start eating away muscle tissue before burning the fat you are trying to lose. This is why someone with anorexia has low body weight but high body fat. You also miss out on important nutrients.

No matter how many calories you burn, you still need a certain amount of calories in order to lose weight effectively. On CalorieKing plans, this amount of calories is referred to as a daily Calorie Target. If you exercise, you move further away from your Calorie Target and therefore need to "eat back" those calories.

Bottom line: Eat enough calories for your body to lose weight effectively and always stay near your daily Calorie Target.