Effect of Allowing Choice of Diet on Weight Loss: A Randomized Trial.
Study Goal
The researchers aimed to determine whether allowing participants to choose between a low-carbohydrate diet (LCD) or a low-fat diet (LFD) would improve weight loss compared to random assignment.
Results Summary
The study found no significant difference in weight loss between the choice group (5.7 kg) and the comparator group (6.7 kg) at 48 weeks. Secondary outcomes, such as dietary adherence and quality of life, were similar between groups.
Population
Outpatients with a BMI ≥30 kg/m² at a Veterans Affairs medical center (older veterans).
Effective Dosage
Not specified
Duration
48 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
choice of diet (low-carbohydrate diet or low-fat diet) | no change | weight loss | outpatients with a body mass index of at least 30 kg/m2 | - | did not improve | #1 |
choice of diet (low-carbohydrate diet or low-fat diet) | decrease | weight | choice group | 5.7 kg (95% CI, 4.3 to 7.0 kg) | estimated mean weight loss was | #2 |
random assignment to a diet (low-carbohydrate diet or low-fat diet) | decrease | weight | comparator group | 6.7 kg (CI, 5.4 to 8.0 kg) | estimated mean weight loss was | #3 |
choice of diet versus random assignment to a diet | decrease | weight loss | - | -1.1 kg (CI, -2.9 to 0.8 kg); P = 0.26 | mean difference was | #4 |
choice of diet versus random assignment to a diet | no change | dietary adherence | - | - | were similar | #5 |
choice of diet versus random assignment to a diet | no change | physical activity | - | - | were similar | #6 |
choice of diet versus random assignment to a diet | no change | weight-related quality of life | - | - | were similar | #7 |
BACKGROUND: Choosing a diet rather than being prescribed one could improve weight loss. OBJECTIVE: To examine whether offering choice of diet improves weight loss. DESIGN: Double-randomized preference trial of choice between 2 diets (choice) versus random assignment to a diet (comparator) over 48 weeks. (ClinicalTrials.gov: NCT01152359). SETTING: Outpatient clinic at a Veterans Affairs medical center. PATIENTS: Outpatients with a body mass index of at least 30 kg/m2. INTERVENTION: Choice participants received information about their food preferences and 2 diet options (low-carbohydrate diet [LCD] or low-fat diet [LFD]) before choosing and were allowed to switch diets at 12 weeks. Comparator participants were randomly assigned to 1 diet for 48 weeks. Both groups received group and telephone counseling for 48 weeks. MEASUREMENTS: The primary outcome was weight at 48 weeks. RESULTS: Of 105 choice participants, 61 (58%) chose the LCD and 44 (42%) chose the LFD; 5 (3 on the LCD and 2 on the LFD) switched diets at 12 weeks, and 87 (83%) completed measurements at 48 weeks. Of 102 comparator participants, 53 (52%) were randomly assigned to the LCD and 49 (48%) were assigned to the LFD; 88 (86%) completed measurements. At 48 weeks, estimated mean weight loss was 5.7 kg (95% CI, 4.3 to 7.0 kg) in the choice group and 6.7 kg (CI, 5.4 to 8.0 kg) in the comparator group (mean difference, -1.1 kg [CI, -2.9 to 0.8 kg]; P = 0.26). Secondary outcomes of dietary adherence, physical activity, and weight-related quality of life were similar between groups at 48 weeks. LIMITATIONS: Only 2 diet options were provided. Results from this sample of older veterans might not be generalizable to other populations. CONCLUSION: Contrary to expectations, the opportunity to choose a diet did not improve weight loss.