Study Suggests Having a Diet Option Assigned vs. Choosing a Diet Leads to Greater Weight Loss among Obese Veterans
A variety of dietary approaches have proven effective for weight management, but regardless of the approach, a higher adherence to dietary recommendations has been the best predictor of weight loss. Therefore, new strategies that maximize dietary adherence are needed to help patients experience maximum health benefits. This randomized trial evaluated whether Veterans allowed the opportunity to choose between two diets would have greater weight loss than Veterans randomly assigned a diet. Study participants with a body mass index (BMI) of >30 (obese) and a regular VA provider were recruited from VA clinics in Durham, NC between May 2011 and June 2012. Veterans were then randomized to the Choice group (n=105) or the Comparator group (n=102). Choice group participants received information about their food preferences and two diet options (low-carbohydrate diet [LCD] or low-fat, reduced-calorie diet [LFD]), and were allowed to switch diets at 12 weeks. Of these Veterans, 61 (58%) chose the LCD and 44 (42%) chose the LFD, with 5 Veterans (3 LCD, 2 LFD) switching diets at 12 weeks. Participants in the Comparator group were randomly assigned to one diet for 48 weeks. All Veterans in this study received group and telephone counseling for 48 weeks. The primary outcome – body weight – was measured at each of the 19 visits over 48 weeks. Secondary outcomes included dietary adherence, physical activity, and weight-related quality of life.
- Contrary to popular opinion, the option of choosing a diet to follow, as opposed to being assigned a diet, did not improve weight loss among obese Veterans.
- At 48 weeks, the estimated mean weight loss was 5.7 kg for Veterans in the Choice group and 6.7 kg for Veterans in the Comparator group.
- Secondary outcomes of dietary adherence, physical activity, and weight-related quality of life were similar between groups.
- The mean age of Veterans in this study was 55 years and the mean BMI was 36; also, 51% were African-American, 27% were women, and 23% had type 2 diabetes.
- Given that diverse diets have proven effective for weight loss, future research might examine matching patients to their optimal diet based on other characteristics (e.g., metabolic profile, genetics) instead of their preferences.
- Having more than two dietary options might have had a broader appeal to study participants.
- There was no comparison group that included those not receiving any diet (usual care).
- Advising study participants with a strong aversion to one diet not to enroll may have weakened the potential benefits of choice on adherence, but this occurred rarely (n = 2).
This study was funded by HSR&D (IIR 09-381). Drs. Yancy, Coffman, Smith, McVay, Oddone, and Voils are part of HSR&D's Center for Health Services Research in Primary Care in Durham, NC.
Yancy W, Mayer S, Coffman C, Smith V, Kolotkin R, Geiselman P, McVay M, Oddone E, Voils C. Effect of Allowing Choice of Diet on Weight Loss: A Randomized Trial. Annals of Internal Medicine. June 16, 2015;162(12):805-14.