Cycling tips: cycling outdoors and healthy diets After exercise, feeling warm and sweating a little is a sign that your body is burning fat. After exercise, feeling warm and sweating a little is a sign that your body is burning fat. (One also sweats when feeling nervous and shy, so not all the sweat and fever is related to fat-burning.) Do not eat 2 hours before your bed time. Usually, 2 hours after meal, your energy (calories) is supplied by carbohydrate in food. 3 hours after meal, your energy (calories) is provided by fat stored in food and