Review: dietary interventions, with or without exercise, promote weight loss more than advice alone
M J Franz
Ms M J Franz, Nutrition Concepts by Franz Inc, Minneapolis, MN, USA;
What are the most effective interventions for weight loss in overweight and obese adults?
PubMed (1997 to Sep 2004) and reference lists.
Study selection and assessment:
English-language, randomised controlled trials (RCTs) that evaluated weight loss interventions in overweight or obese adults and had ⩾1 year follow-up. 80 RCTs (n = 26 455, mean age 23–69 y, 0–100% men) met the selection criteria. At baseline, mean weight was 77–131 kg and mean body mass index was 29–43 kg/m2. The interventions included advice only (28 RCTs), exercise (6 RCTs), diet (51 RCTs), diet plus exercise (17 RCTs), meal replacements (7 RCTs), very-low-energy diet (11 RCTs), orlistat (13 RCTs), and sibutramine (7 RCTs). No RCT on bariatric surgery was found. Study duration ranged from 12 to 60 months. Overall patient follow-up was 69%.
For most interventions, maximum weight loss occurred early in the study (pooled mean weight loss at 6 mo was 0.7 kg for advice only, 2.4 kg for exercise, 4.9 kg for diet, 7.9 kg for diet plus exercise, 8.2 kg for sibutramine, 8.3 kg for orlistat, 8.6 kg for meal replacements, and 18 kg for very-low-energy diet), with some re-gain over time. Except for advice only, mean weight did not completely regress to baseline level by study end. Meta-analysis showed that reduced-energy diets, with or without exercise, resulted in more weight loss than advice alone (table). Meal replacements and weight-management drugs resulted in more weight loss than diet (table). Data from RCTs of very-low-energy diets were insufficient for meta-analysis.
Reduced-energy diets, with or without exercise, promote weight loss more than advice alone. Meal replacement and weight-management drugs promote weight loss more than diet alone. Regardless of intervention type, most weight loss occurs in the first 6 months, with some weight re-gain.
A modified version of this abstract appears in Evidence-Based Medicine.
Franz MJ, VanWormer JJ, Crain AL, et al. Weight-loss outcomes: a systematic review and meta-analysis of weight-loss clinical trials with a minimum 1-year follow-up. J Am Diet Assoc 2007;107:1755–67.
Clinical impact ratings: Family/General practice 6/7; Health promotion 6/7; Obesity 5/7
The obesity epidemic and its negative health implications have made assisting patients in weight loss a priority for nurses. The results of the comprehensive review by Franz et al support guidelines for weight loss: a multifaceted approach of diet, exercise, and behavioural therapy, with the addition of medication if the initial approach is not effective after 6 months.1 Medications and meal replacements, although more effective than diet alone, are not recommended or accessible for all patients and must be accompanied by diet, exercise, and behavioural therapy.
As expected from clinical experience, early weight loss was followed by a plateau. Weight re-gain occurred with all interventions, including after discontinuation of weight loss medications. It is important to note that the long-term (>1 y) safety of these medications is unknown. On average, participants in diet and exercise, medication, or meal replacement interventions maintained a 4–8% weight loss at ⩾1 year, approximating the 5–10% weight loss advised for health benefits.
The role of professional support in maintaining weight loss was discussed by Franz et al; however, the included trials gave little description of the types of support provided. 1 study reported very little weight re-gain in patients who received even minimal in-person support.2 Although evidence of the effect of support on weight loss is unclear, the results of this review definitively point to the need for ongoing follow-up, support, and monitoring for patients to safely achieve and maintain weight loss.1 Collaboration is necessary as practitioners and patients work toward individual weight management goals.