Metabolic and weight loss effects of long-term dietary intervention in obese patients: four-year results.

To investigate the contribution of meal and snack replacements for long-term weight maintenance and risk factor reduction in obese patients. Prospective, randomized, two-arm, parallel intervention for 12 weeks followed by a prospective single-arm 4-year trial in a University Hospital clinic. One hundred patients, >18 years old and with a body mass index > 25 and < or = 40 kg/m2, were prescribed a 1,200 to 1,500 kcal/d control diet (Group A) or an isoenergetic diet, including two meal and snack replacements (vitamin- and mineral-fortified shakes, soups, and bars) and one meal high in fruits and vegetables (Group B). Following a 3 months of weight loss, all patients were prescribed the same energy-restricted diet (1,200 to 1,500 kcal) with one meal and one snack replacement for an additional 4 years. All 100 patients were evaluated at 12 weeks. Mean percentage weight loss was 1.5 +/- 0.4% and 7.8 +/- 0.5% (mean +/- SEM) for Groups A and B, respectively. At 12 weeks systolic blood pressure, plasma triacylglycerol, glucose, and insulin concentrations were significantly reduced in Group B, whereas no changes occurred in Group A. After 4 years, 75% of the patients were evaluated. Total mean weight loss was 3.2 +/- 0.8% for Group A and 8.4 +/- 0.8% (mean +/- SEM) for Group B. Both groups showed significant improvement in blood glucose and insulin (p < 0.001), but only Group B showed significant improvement in triacylglycerol and systolic blood pressure compared to baseline values (p < 0.001). Providing a structured meal plan via vitamin- and mineral-fortified liquid meal replacements is a safe and effective dietary strategy for obese patients. Long-term maintenance of weight loss with meal replacements can improve certain biomarkers of disease risk.