LGI diet ameliorates some plasma lipid parameters, decreases total fat mass, and tends to increase lean body mass without changing body weight. The objective of the study was to evaluate whether a 5-week low–glycemic index (LGI) diet versus a high–glycemic index (HGI) diet can modify glucose and lipid metabolism as well as total fat mass in nondiabetic men.
In this study, 11 healthy men were randomly allocated to 5 weeks of an LGI or HGI diet separated by a 5-week washout interval in a crossover design.
What the study found was that the LGI diet resulted in lower postprandial plasma glucose and insulin profiles and areas under the curve (AUCs) than the HGI diet. A 5-week period of the LGI diet lowered plasma triacylglycerol excursion after lunch (AUC, P < 0.05 LGI vs. HGI). These modifications were associated with a decrease in the total fat mass by 700 g (P < 0.05) and a tendency to increase lean body mass (P < 0.07) without any change in body weight. This decrease in fat mass was accompanied by a decrease in leptin, lipoprotein lipase, and hormone-sensitive lipase RNAm quantities in the subcutaneous abdominal adipose tissue (P < 0.05).
We concluded that 5 weeks of an LGI diet ameliorates some plasma lipid parameters, decreases total fat mass, and tends to increase lean body mass without changing body weight. These changes were accompanied by a decrease in the expression of some genes implicated in lipid metabolism. One possible pathway by which alterations in insulin sensitivity might alter lipid metabolism is through the action of insulin on LPL. Actually, the LPL level in adipose tissue is positively correlated with insulinemia (31). Consistent with the reduction of postprandial insulinemia and triacylglycerol, we found that after an LGI diet, there was a significant reduction in LPL expression in adipose tissue, which could have induced a reduction in fat depot. Such a diet could be of benefit to healthy, slightly overweight subjects and might play a role in the prevention of metabolic diseases and their cardiovascular complications. Diabetes Care 25:822-828, 2002