Insulin and leptin act as long-term peripheral signals of energy status to the central nervous system and are involved in the regulation of food intake and energy expenditure. In monkeys, fructose administration does not stimulate either insulin or leptin secretion, which may mean that the calories consumed as fructose are not recognized by the central nervous system and resulting in inappropriate adjustments of appetite and energy expenditure. This study will establish the effects of high fructose versus high glucose meals on circulating insulin and leptin levels in humans and determine if differences in insulin and leptin subsequently affect appetite and food intake. Circulating leptin concentrations and appetite parameters will be measured in women consuming three meals in a 24-hour period (60 percent carbohydrate of which half is either free fructose or free glucose), using a randomized cross-over design. The expected results are that circulating leptin concentrations will be lower following the high fructose meals and sensations of hunger and food intake will be greater.
• Consumption of high fructose (30 percent of energy) meals resulted in lower circulating insulin and leptin concentrations over a 24-hour period compared to high glucose (30 percent of energy) meals in young women.
• Circulating ghrelin levels were suppressed following the high fructose meals but less so than after the high glucose meal.
• Post prandial and subsequent fasting triglycerides were higher after high fructose meals compared to high glucose meals.
• Response to high fructose meals is similar to that following high fat/low carbohydrate meal.
Teff KL, Elliott SS, Tschöp M, Kieffer TJ, Rader D, Heiman M, Townsend RR, Keim NL, D'Alessio D, Havel PJ. Dietary fructose reduces circulating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. J Clin Endocrinol Metab. 2004 Jun;89(6):2963-72.