CHANGES IN LIPOPROTEIN SUBFRACTIONS DURING DIET-INDUCED AND EXERCISE-INDUCED WEIGHT-LOSS IN MODERATELY OVERWEIGHT MEN

We studied separately the effects of weight loss by calorie restriction (dieting) and by calorie expenditure (primarily, running) on lipoprotein subfraction concentrations in sedentary, moderately overweight men assigned at random into three groups as follows: exercise without calorie restriction (n = 46), calorie restriction without exercise (n = 42), and control (n = 42). Plasma lipoprotein mass concentrations were measured by analytic ultracentrifugation for flotation rates (F1.200, S(f)0) within high density lipoprotein (HDL) (F1.200 0-9), low density lipoprotein (LDL) (S(f)0 0-12), intermediate density lipoprotein (IDL) (S(f)0 12-20), and very low density lipoprotien (VLDL) (S(f)0 20-400) particle distributions. Particle diameter and flotation rate of the most abundant LDL species were determined by nondenaturing polyacrylamide gradient gel electrophoresis and analytic ultracentrifugation, respectively. During the 1-year trial, the exercisers ran (mean ± SD) 15.6 ± 9.1 km/wk, and the dieters ate 340 ± 71 fewer kilocalories per day than at baseline. Total body weight was reduced significantly more in dieters (-7.2 ± 4.1 kg) and exercisers (-4.0 ± 3.9 kg) than controls (0.6 ± 3.7 kg). As compared with mean changes in controls, the exercisers and dieters significantly increased HDL2 mass (48.6% and 47.1%, respectively), decreased VLDL mass (-23.9% and -25.5%), and increased LDL peak particle diameter (2.4 and 3.2 Å). When adjusted to an equivalent change in body mass index by analysis of covariance, 1) exercise-induced and diet-induced weight loss produced comparable mean changes in the mass of small LDL and VLDL, and in LDL peak particle diameter; 2) the exercisers versus control group difference in HDL2 was attributed to the exercisers' reduced body mass index; and 3) HDL2 increased significantly less in dieters than in exercisers. In dieters, low calorie intake might mitigate the effects of weight loss on HDL2.