Specific and Differential Responses of Serum Lipoproteins to Weight Loss of > 100 Pounds.

Objective:  Weight loss improves many risk factors for cardiovascular disease including serum lipoprotein levels.

Method:  We assessed serial changes in serum lipoproteins of 118 severely obese individuals who have lost >100 pounds in our intensive behavioral weight loss program (HMR^® Program for Weight Management^TM) over the past 8 years.

Results:  These individuals lost, on average, 134 pounds over 43 weeks using low-calorie diets with meal replacement shakes and entrees.  While 75% met the criteria for dyslipidemia, only 9% were initially on treatment with lipid-lowering agents; all agents were discontinued during weight loss.  Lipid measurements were done biweekly or monthly.  Changes from baseline to final values were as follows:  cholesterol (chol), -16 + 2% (SE); LDL-cholesterol (LDL-c), -18 + 2%; HDL-cholesterol (HDL-c), +3 + 2%; and triglycerides (TG), -33 + 3%.  Serum cholesterol values decreased progressively over time reaching a nadir at 20 weeks of -22 + 2% below baseline values and then increasing slightly by 1—2%; LDL-c levels decreased similarly reaching a nadir of -23 + 3% at 20 weeks and then increasing by ~8% by 44 weeks.  Higher baseline LDL-c values (> 160 mg/dl) were associated with significantly greater decreases (-30 + 4%, p < 0.001) than lower (< 100 mg/dl) baseline values (-14 + 2%).  HDL-c values decreased rapidly, reaching a nadir of -15 + 4% at 6 weeks, and then steadily increased to above baseline values by 52 weeks.  HDL-c values decreased more rapidly and to a greater degree in women (-18 + 5%) than in men (-12 + 4%).  However, they returned to baseline values by 44 weeks in both sexes.  TG values decreased steadily over time and reached a nadir at 36 weeks of -30 + 4% compared to baseline.  Follow-up values are available for 20 patients at 40—60 weeks after completing weight loss.  Chol, LDL-c and TG had returned towards baseline values at follow-up but HDL-c values were ~15% higher than baseline.

Conclusion:  Thus, substantial weight loss has selective effects on lipoproteins with LDL-c gradually decreasing and then slowly increasing; TG decreasing progressively; and HDL-c decreasing rapidly in 4—8 weeks, returning to baseline at completion of weight loss, and then significantly increasing at 1 year follow-up.  Overall, weight loss substanially improves all lipoprotein risk factors.