Fructose is a monosaccharide present naturally in foods as fruit, vegetables and honey. In fruit, vegetables and table sugar it is also present as a disaccharide (sucrose), where it is joined with glucose. The intake of fructose has increased dramatically in the last decades. The increase is
Some people appear to be more resistant than others to gaining weight when they overeat, though they do not increase their physical activity. This may indicate that adaptive mechanisms exist, which lead to wasting as heat part of the excess calories taken in. Such mechanisms exist in rodents