Influence of weight reduction on plasma lipoproteins in obese patients.

To determine the influence of weight reduction on plasma lipoproteins, studies were carried out in 15 nondiabetic patients of varying degrees of obesity and four obese insulin-dependent diabetics. All studies were carried out on a metabolic ward and patients underwent three dietary periods: Period I, 4 to 5 weeks of weight maintenance in the obese state; Period II, caloric restriction to 1000 kcal/day to a weight loss of within 10% of ideal body weight; and Period III, again weight maintenance for 4 to 5 weeks near ideal body weight. Similar results were obtained for both nondiabetics and diabetics. Many patients had mildly elevated plasma triglycerides in Period I; they fell to the normal range in Period II and remained low in Period III. Total cholesterol levels decreased early in Period II, but levels began to rise near the end of caloric restriction, and in Period III, they were similar to Period I. Low density lipoprotein cholesterol levels followed a pattern similar to that of total cholesterol. High density lipoprotein cholesterol was relatively low in Period I (38 +/- 2 mg/dl +/- SEM); throughout weight loss, levels tended to rise, and in Period III, the average high density lipoprotein cholesterol was significantly higher (46 +/- 2 mg/dl).