THOMAS A. WADDEN
ROBERT I. BERKOWITZ
Very-low-calorie diets (VLCDs) reached the height of their popularity in 1988, when Oprah Winfrey revealed to her 12 million viewers that she had lost 67 pounds by consuming a liquid supplement. Use of these diets, however, declined sharply a year later, when Ms. Winfrey announced that she had regained her lost weight and would “never diet again.” Now, more than a decade later, interest in liquid supplements is growing again. This chapter provides an overview of VLCDs and recommendations for their use.
An expert panel convened by the National Heart, Lung, and Blood Institute (NHLBI) recently defined low-calorie diets as those providing 800–1,200 kcal/day and VLCDs as providing < 800 kcal daily. These widely accepted definitions overlook a critical issue, which is the size of the energy deficit induced by a given diet in a given individual. It is inconsistent to require a short, obese woman with a daily energy expenditure of only 1,500 kcal/day to receive extensive medical monitoring while consuming a 700-kcal/day VLCD, and not an obese man with a daily energy expenditure of 3,000 kcal/day on a 1,200-kcal/ day low-calorie diet. The energy deficit, weight loss, and potential effects are far greater for the man, although he is not consuming a VLCD. This example illustrates the need to define a VLCD in terms of the energy requirements of the individual. Several investigators have suggested that a VLCD is any diet that provides ≤ 50% of an individual’s predicted resting energy requirements.
Regardless of how a VLCD is defined, restricting energy intake further below 800 kcal/day confers only marginal benefit. Three randomized, controlled trials found no significant differences in weight loss between diets providing 800 kcal/day and those with as