High glycemic index foods, overeating, and obesity.
OBJECTIVE
The prevalence of obesity has increased dramatically in recent years. However, the role of dietary composition in body weight regulation remains unclear. The purpose of this work was to investigate the acute effects of dietary glycemic index (GI) on energy metabolism and voluntary food intake in obese subjects.


METHODS
Twelve obese teenage boys were evaluated on three separate occasions using a crossover study protocol. During each evaluation, subjects consumed identical test meals at breakfast and lunch that had a low, medium, or high GI. The high- and medium-GI meals were designed to have similar macronutrient composition, fiber content, and palatability, and all meals for each subject had equal energy content. After breakfast, plasma and serum concentrations of metabolic fuels and hormones were measured. Ad libitum food intake was determined in the 5-hour period after lunch.


RESULTS
Voluntary energy intake after the high-GI meal (5.8 megajoule [mJ]) was 53% greater than after the medium-GI meal (3.8 mJ), and 81% greater than after the low-GI meal (3.2 mJ). In addition, compared with the low-GI meal, the high-GI meal resulted in higher serum insulin levels, lower plasma glucagon levels, lower postabsorptive plasma glucose and serum fatty acids levels, and elevation in plasma epinephrine. The area under the glycemic response curve for each test meal accounted for 53% of the variance in food intake within subjects.


CONCLUSIONS
The rapid absorption of glucose after consumption of high-GI meals induces a sequence of hormonal and metabolic changes that promote excessive food intake in obese subjects. Additional studies are needed to examine the relationship between dietary GI and long-term body weight regulation.
Ludwig
D S
DS
Division of Endocrinology, Department of Medicine, Children's Hospital,Boston, 300 Longwood Ave, Boston, MA 02115, USA.
Majzoub
J A
JA
Al-Zahrani
A
A
Dallal
G E
GE
Blanco
I
I
Roberts
S B
SB
D000293:Adolescent; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D019422:Dietary Sucrose / Q000008:administration & dosage / Q000378:metabolism; D002149:Energy Intake / Q000502:physiology*; D006801:Humans; D006815:Hunger; D007328:Insulin / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology; D012044:Regression Analysis
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D007328:Insulin