And in fact they have to be converted to fat. There are only two other options:
stored in muscles as glycogen - however, the muscle stores can only store up to 1600 calories so they may be full. Also, once sugar gets into a muscle it can't get out - it can only be used by that particular muscle.
used by the brain - however the brain doesn't need more than 500 kcal per day. (and can live with as little as 120 kcal / 30g of glucose provided that the rest of the energy is supplied by ketones)
So... exercise doesn't help lose weight, but it sure helps prevent weight gain when eating carbs. With the amount of carbs we eat nowadays and the low amounts of physical activity, its no wonder at all we store a lot of fat.
stored in muscles as glycogen - however, the muscle stores can only store up to 1600 calories so they may be full. Also, once sugar gets into a muscle it can't get out - it can only be used by that particular muscle.
used by the brain - however the brain doesn't need more than 500 kcal per day. (and can live with as little as 120 kcal / 30g of glucose provided that the rest of the energy is supplied by ketones)
So... exercise doesn't help lose weight, but it sure helps prevent weight gain when eating carbs. With the amount of carbs we eat nowadays and the low amounts of physical activity, its no wonder at all we store a lot of fat.