To assess the effect of weight loss on the plasma lipid and remnant-like lipoprotein cholesterol (RLPc) response to a high-fat or a high-carbohydrate meal in a population of obese women.
Nutritional intervention study.
Sixteen obese women (mean body mass index (BMI): 37.6+/-5 kg/m(2)).
Subjects were asked to follow an energy-restricted diet (800 kcal/day) for 7 weeks, followed by a 1-week maintenance diet. Before and after weight loss, each participant was given (in random order) two iso-energetic meals containing either 80% fat and 20% protein (the high-fat meal) or 80% carbohydrate and 20% protein (the high-carbohydrate meal). Blood samples were collected over the following 10-h period. A two-way analysis of variance with repeated measures was used to assess the effect of the meal and postprandial time on biological variables and postprandial responses (notably RLPc levels).
Weight loss was associated with a significant decrease in fasting triglyceride (P=0.0102), cholesterol (P<0.0001), low-density lipoprotein cholesterol (P=0.0003), high-density lipoprotein-cholesterol (P=0.0009) and RLPc (P=0.0015) levels. The triglyceride response to the high-fat meal was less intense after weight reduction than before (interaction P<0.002). This effect persisted after adjustment on baseline triglyceride levels. The triglyceride response to the high-carbohydrate meal was biphasic (i.e. with two peaks, 1 and 6 h after carbohydrate intake). After adjustment on baseline values, weight reduction was associated with a trend towards a reduction in the magnitude of the second triglyceride peak (interaction P<0.054). In contrast, there was no difference in postprandial RLPc responses before and after weight loss, again after adjustment on baseline levels.
Our data suggest that weight loss preferentially affects postprandial triglyceride metabolism.