Objectives: To determine the efficacy of two dietary therapies in both the short term (hospitalisation) and the longer term treatment of severe obesity.
Design: A descriptive study of two patient groups with obesity defined by a body mass index of greater than 30 kg/m2.
Setting: A multidisciplinary weight control program in a tertiary care hospital.
Patients: All admissions to hospital of patients on the weight control program for initiation of weight loss during a period of 48 months.
Intervention: A standard kilojoule reduction regimen or the use of complete, followed by partial, long term meal substitution with a very low energy liquid diet (VLED), coupled with an exercise and a behavioural modification program.
Outcome measures: Weight loss during and after hospitalisation was measured in both dietary regimen groups.
Results: Both diets induced weight loss in hospital. Men prescribed VLED lost significantly more weight, 8.3 +/- 0.8 kg (mean +/- SEM) than women prescribed this diet (5.5 +/- 0.5 kg) or standard kilojoule restriction (5.1 +/- 0.8 kg).
Conclusions: VLED and standard kilojoule restriction are both effective for the treatment of severe obesity, particularly in a controlled environment (hospitalisation). In the longer term, VLED is an effective method of maintaining weight loss. Lack of continuing weight loss may reflect the patients who were initially placed on this regimen--small eaters with a presumed high metabolic efficiency.