VERY-LOW-CALORIE DIETS

Objective.-To provide an overview of the published scientific informat ion on the safety and efficacy of very low-calorie diets (VLCDs) and t o provide rational recommendations for their use. Data Sources and Ext raction.-Original reports obtained through a MEDLINE search for 1966 t hrough 1992 on VLCDs or reducing diets plus obesity, supplemented by a manual search of bibliographies and the opinions of experts in the fi eld of nutrition and weight loss therapy for obesity. Only studies of humans were cited. Data Synthesis.-Current VLCDs are usually provided in the context of comprehensive treatment programs, during which usual food intake is completely replaced by specific foods or liquid formul as containing 3350 kJ/d (800 kcal/d) or less. Weight loss on VLCDs ave rages 1.5 to 2.5 kg/wk; total loss after 12 to 16 weeks averages 20 kg . These results are superior to standard low-calorie diets of 5020 kJ/ d (1200 kcal/d), which lead to weight losses of 0.4 to 0.5 kg/wk and a n average total loss of only 6 to 8 kg. There is little evidence that intakes of less than 3350 kJ/d (800 kcal/d) result in better weight lo sses than 3350 kJ. Intake of at least 1 g/kg of ideal body weight per day of protein of high biologic value appears to be important in helpi ng to preserve lean body mass. Serious complications of modern VLCDs a re unusual, cholelithiasis being most common. Conclusions.-Current VLC Ds are generally safe when used under proper medical supervision in mo derately and severely obese patients (body mass index [weight in kilog rams divided by height in meters squared] >30) and are usually effecti ve in promoting significant short-term weight loss, with concomitant i mprovement in obesity-related conditions. Long-term maintenance of wei ght lost with VLCDs is not very satisfactory and is no better than wit h other forms of obesity treatment. Incorporation of behavioral therap y and physical activity in VLCD treatment programs seems to improve ma intenance.