The glycemic index (GI) is a measure of the ability of individual foods to elevate blood sugar over 2 hours compared to eating a simple sugar such as glucose. High-GI foods digest rapidly and have various negative health effects. Low-GI foods digest slowly and are believed to be beneficial to our health.
This review is of the ability of GI to predict appetite, hunger and satiety (fullness) through published studies. High-GI foods were found to increase hunger and lower satiety over the short term, possibly because of hypoglycemia caused by insulin produced in response to the rising blood glucose. High-GI test meals resulted in people eating less at subsequent meals.
Four short term studies show that eating high-GI food increases the food intake at later meals. After a low-GI breakfast, adolescents ate less lunch than those eating a high-GI breakfast. Low-GI meals produce lower insulin responses. The blood response to glucose and the response of insulin to blood glucose are associated with appetite, hunger and satiety. As blood glucose drops below the person’s base level, satiety ends and appetite and hunger return.
Low-GI foods have been promoted for treatment of the obesity seen frequently today. The results of long-term studies showed varying responses of appetite/satiety to foods of various glycemic indices. There is inadequate evidence to support the use of low-GI foods in the treatment of obesity.
Long-term studies do not show that low-GI diets reduce appetite or hunger unless there was a definite change in blood glucose level. Low-GI diets do not result in weight loss. The diets did not result in changes of blood glucose or insulin levels.
Two appetite/satiety control hormones are leptin and ghrelin. Increased insulin or glucose levels increase blood leptin levels and suppress insulin ghrelin levels. Leptin is the satiety hormone. Ghrelin is the appetite stimulating hormone.
CONCLUSION: The authors were unable to determine that GI could be used as a predictor of appetite/satiety or in the treatment of obesity. The GI of any particular food is not reflected in mixed meals. No relationship could be shown between GI, leptin (satiety hormone) and ghrelin (appetite hormone).
NOTE: Read about the glycemic benefit of chlorogenic acid.
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