4 Experimental Twin Studies

There are considerable individual differences in responses to various dietary manipulations, such as diets rich in cholesterol or in saturated fats. The same phenomenon has been observed in response to chronic overfeeding. For instance, in the Vermont overfeeding study, body weight gain varied among subjects and was below the expected weight gain based upon the ingested caloric surplus (1). Much has been learned from experimental overfeeding, dietary energy restriction, or exercise-induced negative energy balance studies conducted with human subjects.