1. An unsupplemented 4200 kJ (1000 kcal) diet emphasizing large quantities of relatively unrefined complex carbohydrates was evaluated among sixty obese adults for its effectiveness and nutritional adequacy in a long-term weight-control programme. Patients were followed individually as outpatients by a physician and dietician–an average of thirteen visits over 26 weeks. Assessment of health indices included anthropometric measurements, blood pressure, lipid levels and assays for seven vitamins, β–carotene and iron.
2. Weight loss averaged 8.2 kg or 24% of excess weight during the 6 months of active treatment. Over an average of 17 months of post-treatment follow-up, 44% of patients continued to lose weight and 92% remained below pretreatment levels.
3. Average skinfold thickness fell 7mm (p < 0·001) whereas muscle mass was maintained (arm muscle circumference+10mm, not significant; creatinine-height index + 3% of standard (Bistrian et al. 1975; not significant). Systolic and diastolic bleed pressure fell 7 and 5 mmHg respectively (P < 0·01). Total serum cholesterol and triglyceridesfell 200 and 660 mg/1 respectively (P < 0·01), while high-density-lipoprotein-cholesterol remained statistically unchanged. Mean serum levels of retinol, β-carotene, folate, vitamin B12, ascorbic acid, Fe and transferrin saturation, and activity coefficients for thiamin, riboflavin and pyridoxine were within normal limits after periods of treatment ranging from 5 to 84 weeks.
4. An earlier age of onset of obesity tended to be associated with greater weight lossduring treatment and lesser weight rebound during follow-up.
5. The results indicate that the experimental diet, without supplementation, was nutritionally adequate as well as effective for long-term weight control.