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Effect of Allowing Choice of Diet on Weight Loss: A Randomized TrialEffect of Allowing Choice of Diet on Weight Loss

William S. Yancy Jr., MD; Stephanie B. Mayer, MD; Cynthia J. Coffman, PhD; Valerie A. Smith, DrPH; Ronette L. Kolotkin, PhD; Paula J. Geiselman, PhD; Megan A. McVay, PhD; Eugene Z. Oddone, MD; and Corrine I. Voils, PhD
[+] Article, Author, and Disclosure Information

From the Center for Health Services Research in Primary Care, Department of Veterans Affairs, and Duke University Medical Center, Durham, North Carolina; Virginia Commonwealth University, Richmond, Virginia; Sogn og Fjordane University College and Førde Central Hospital, Førde, Norway; Vestfold Hospital Trust, Tønsberg, Norway; and Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana.

Note: Drs. Coffman and Smith conducted the data analysis. Drs. Yancy and Coffman, who are affiliated with the Durham VAMC and Duke University Medical Center, had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Disclaimer: This article is the result of work done with resources and the use of facilities at the Durham VAMC. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs, the U.S. government, Duke University, Pennington Biomedical Research Center, Louisiana State University, or Virginia Commonwealth University.

Acknowledgment: The authors thank Marsha Turner, Leslie Gaillard, Terry Ervin, and Jahdai Dawes for their assistance in delivering the intervention and collecting data.

Grant Support: By the Department of Veterans Affairs (IIR 09-381).

Disclosures: Dr. Yancy reports grants from the Department of Veterans Affairs during the conduct of the study and personal fees from Nutrisystem and the University of Pennsylvania outside the submitted work. Dr. Smith reports a grant from the Department of Veterans Affairs during the conduct of the study. Dr. Kolotkin reports personal fees from the Department of Veterans Affairs Health Services Research & Development during the conduct of the study and a patent with royalties paid for the Impact of Weight on Quality of Life-Lite questionnaire. Dr. Geiselman reports an honorarium from the Department of Veterans Affairs during the conduct of the study and royalties from the Pennington Biomedical Research Center of Louisiana State University for intellectual property. Authors not named here have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M14-2358.

Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer.

Reproducible Research Statement:Study protocol and statistical code: The authors are willing to share the study's protocol and statistical code to approved persons through written agreements with the authors (e-mail, yancy006@mc.duke.edu) and as approved by the Durham VAMC Institutional Review Board. Data set: Not available.

Requests for Single Reprints: William S. Yancy Jr., MD, Durham VA Medical Center (152), 508 Fulton Street, Durham, NC 27705; e-mail, yancy006@mc.duke.edu.

Current Author Addresses: Drs. Yancy, Coffman, Smith, McVay, Oddone, and Voils: Durham VA Medical Center (152), 508 Fulton Street, Durham, NC 27705.

Dr. Mayer: Virginia Commonwealth University, MCV Campus, PO Box 980111, Richmond, VA 23298-0111.

Dr. Kolotkin: Duke University Medical Center, 932 Ninth Street, Durham, NC 27705.

Dr. Geiselman: Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808.

Author Contributions: Conception and design: W.S. Yancy, C.J. Coffman, P.J. Geiselman, E.Z. Oddone, C.I. Voils.

Analysis and interpretation of the data: W.S. Yancy, S.B. Mayer, C.J. Coffman, V.A. Smith, R.L. Kolotkin, P.J. Geiselman, M.A. McVay, E.Z. Oddone, C.I. Voils.

Drafting of the article: W.S. Yancy, C.J. Coffman, R.L. Kolotkin.

Critical revision of the article for important intellectual content: W.S. Yancy, S.B. Mayer, C.J. Coffman, V.A. Smith, R.L. Kolotkin, P.J. Geiselman, M.A. McVay, E.Z. Oddone, C.I. Voils.

Final approval of the article: W.S. Yancy, S.B. Mayer, C.J. Coffman, V.A. Smith, R.L. Kolotkin, P.J. Geiselman, M.A. McVay, E.Z. Oddone, C.I. Voils.

Provision of study materials or patients: W.S. Yancy, C.I. Voils.

Statistical expertise: C.J. Coffman, V.A. Smith.

Obtaining of funding: W.S. Yancy, C.J. Coffman, P.J. Geiselman, C.I. Voils.

Administrative, technical, or logistic support: W.S. Yancy, C.J. Coffman, E.Z. Oddone.

Collection and assembly of data: W.S. Yancy, S.B. Mayer, C.J. Coffman.


Ann Intern Med. 2015;162(12):805-814. doi:10.7326/M14-2358
Text Size: A A A

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.

Primary Funding Source: Department of Veterans Affairs.

Figures

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Appendix Figure 1.

Initial diabetes medication adjustment.

HbA1c = hemoglobin A1c; Met = metformin; Secret = secretagogues; TZD = thiazolidinediones.

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Appendix Figure 2.

Medication adjustment for follow-up hypoglycemia in patients taking medication in addition to metformin.

GLP-1 = glucagon-like peptide-1.

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Appendix Figure 3.

Medication adjustment for follow-up hypoglycemia in patients taking metformin only.

am = morning; bid = twice daily; pm = evening; qd = every day.

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Appendix Figure 4.

Medication adjustment for hypertensive patients taking medication.

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Figure 1.

Study flow diagram.

LCD = low-carbohydrate diet; LFD = low-fat diet.

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Figure 2.

Mean weight trajectories and 95% CIs over 48 wk.

Estimated from linear mixed models.

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Appendix Figure 5.

Smoothed spline trajectories of weight over 48 wk, by diet type and group (dark blueandred lines), and observed mean trajectories of weight over 48 wk, by diet type and group (light blueandpink lines).

LCD = low-carbohydrate diet; LFD = low-fat diet.

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Tables

References

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Comments

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Comment
Posted on June 24, 2015
Sherry L. Pagoto, PhD, Brad Appelhans
University of Massachusetts Medical School and Rush University Medical Center
Conflict of Interest: None Declared
We applaud Yancy and colleagues1 trial examining the impact of diet choice on weight loss. The trial’s focus on behavioral determinants is a refreshing contrast to the multitude of prior diet comparison studies that have failed to support the superiority of any one particular diet for weight loss.2
The hypothesis for this trial was that patient choice of diet (low-fat vs low-carb) may promote diet adherence, and therefore improve weight loss, compared to when diets are randomly assigned.3 Based on the lack of a difference in weight loss between the Choice Group and Assigned Diet Group, the authors conclude that “the opportunity to choose a diet did not improve weight loss.” However, it appears that patients’ diet choices were made only after being counseled by interventionists to choose the diet most consistent with their dietary preferences, which were assessed upon enrollment. Indeed, over 70% of subjects in the Choice Group chose the diet that matched their food preferences. While providing information that enables patients to make an informed choice is consistent with shared decision making, actively promoting concordance between one’s food preferences and diet plan may have skewed the decision making process. We do not know what choice the participant would have made without counseling or with a different counseling approach. In fact, one could argue for counseling participants toward the opposing perspective of choosing a diet plan that minimizes exposure to temptation from preferred foods. The fact that most subjects in the Choice Group aligned their diet plans with their food preferences suggests that the effects of choice and the counseling procedures were conflated.
It is also noteworthy that participants’ food preferences were categorized based on macronutrient content. Whether human food preferences strongly cluster according to macronutrient content, rather than other factors such as palatability, texture, sweet versus savory, flavors, or form is unknown. While the proportion of subjects classified into high-carbohydrate and high-protein preference groups is reported, the strength of these preferences is not. As diet choice appears to have been intentionally tied to macronutrient preferences, the lack of differences between the choice groups may simply reflect a lack of strong macronutrient preferences.
Yancy et al.’s investigation underscores the need for behavioral research that sheds light on the factors driving choice that actually lead to improved dietary adherence and weight loss; otherwise it is difficult to know how to counsel patients on how to make an informed choice.
1. Yancy WS, Jr., Mayer SB, Coffman CJ, et al. Effect of Allowing Choice of Diet on Weight Loss: A Randomized Trial. Ann. Intern. Med. Jun 16 2015;162(12):805-814.
2. Pagoto SL, Appelhans BM. A call for an end to the diet debates. JAMA. Aug 21 2013;310(7):687-688.
3. Yancy WS, Jr., Coffman CJ, Geiselman PJ, et al. Considering patient diet preference to optimize weight loss: Design considerations of a randomized trial investigating the impact of choice. Contemp Clin Trials. May 2013;35(1):106-116.


Comment
Posted on July 6, 2015
Daniel López-Hernández, PhD
CENINVEC, Mexico
Conflict of Interest: None Declared
I read with great interest the recently article published by Yancy et al., (1) where authors examining the impact of diet choice on weight loss using a double-randomized preference trial.


Although the authors did not find significant difference on mean weight loss between the choice group and the comparator group, this study opened a new hypothesis and questions about the actual influence of existing nutritional programs and the possibility to incorporate new programs based-on the patient´s empowerment. The present study raises several questions about the control of variables such as the educational intervention sessions, dietary preferences, shared decision making, the counseling approach, the number of educational sessions necessary to impact in reducing the weight of patients. Empowerment refers to the ability of a person to develop and acquire cognitive behavioral tools that allow he or she change their lifestyle to display the ability to live on behaviors that promote health employing the resources of their environment. Therefore, what type of information enables patients to make an informed choice on their election of diet?, what kind of variables can bias the decision-making process?, what is the influence of family and environment in the dietary preference of patients? The patient empowerment could influence the develop of new Models of Primary Health Care for the development of prevention strategies?, How the medication adjustment affects weight loss?, how the medication interacts with diet for control of weight loss and other variables?


In conclusion, the present study allows us to observe that there are more issues that need to be taken into consideration health public systems for nutritional programs and the clinical practice guidelines. More studies like this are needed to answer more questions.


References
1. Yancy WS Jr, Mayer SB, Coffman CJ, et al. Effect of Allowing Choice of Diet on Weight Loss: A Randomized Trial. Ann Intern Med. 2015;162(12):805-14.


2. Mantwill S, Fiordelli M, Ludolph R, Schulz PJ. EMPOWER-support of patient empowerment by an intelligent self-management pathway for patients: study protocol. BMC Med Inform Decis Mak. 2015;15:18.


3. Thesen J. From oppression towards empowerment in clinical practice-offering doctors a model for reflection. Scand J Public Health Suppl 2005; 66: 47-52.


4. Aveiro M, Santiago LM, Lopes Ferreira P, Simões JA. Fiability Study of Diabetes Empowerment Scale: Short Version. Acta Med Port. 2015;28(2):177-81. [Article in Portuguese].


5. Rossi MC, Lucisano G, Funnell M, et al. Interplay among patient empowerment and clinical and person-centered outcomes in type 2 diabetes. The BENCH-D study. Patient Educ Couns. 2015;pii: S0738-3991(15)00233-5.
Response to Pagoto and Appelhans
Posted on August 3, 2015
William S. Yancy, Jr., Megan A. McVay, Corrine I. Voils
Center for Health Services Research in Primary Care, Department of Veterans Affairs, and Duke University Medical Center, Durham, North Carolina
Conflict of Interest: None Declared
We greatly appreciate the supportive comments from Pagoto and Appelhans regarding our study. We agree with their point that the effects of choice and the counseling procedures were conflated—indeed, this will always be the case if counseling is provided to a person faced with a choice. To clarify our study procedures, however, participants were not advised to select “the diet most consistent with their dietary preferences.” (1) Instead, we encouraged them to use all information provided and any additional information they obtained on their own when making their choice, and although food preference information was provided, they were explicitly informed that they could choose a diet consistent with or opposite of their food preferences. This is evidenced by the 29% who selected the diet that was not most closely aligned with their food preferences. Furthermore, when asked the reason for their diet selection, participants rated several factors as similar or of greater importance than food preferences, including perceptions of diet effectiveness and the description of diets provided (2).We also agree with the second point that other factors besides macronutrient content may drive food preferences. For this reason, we described the diets in detail to participants, listing potential food items and menus for each diet. Therefore, the participants were provided a comprehensive picture of the two diets on which to base their decision using any food preference factors (or other factors, e.g., health, cost, convenience) that were important to them. Finally, we wholeheartedly agree that more data is needed on the factors “driving choice that actually lead to improved dietary adherence and weight loss” and we are currently conducting follow-up analyses to answer that question.

1. Pagoto SL, Appelhans B. Comment. Ann Intern Med. 2015;XX:xxx-xxx.
2. McVay MA, Voils CI, Coffman CJ, Geiselman PJ, Kolotkin RL, Mayer SB, Smith VA, Gaillard L, Turner MJ, Yancy WS Jr. Factors associated with choice of a low-fat or low-carbohydrate diet during a behavioral weight loss intervention. Appetite. 2014;83:117-124.
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Summary for Patients

Effect of Allowing Choice of Diet on Weight Loss

The full report is titled "Effect of Allowing Choice of Diet on Weight Loss. A Randomized Trial." It is in the 16 June 2015 issue of Annals of Internal Medicine (volume 162, pages 805-814). The authors are W.S. Yancy Jr., S.B. Mayer, C.J. Coffman, V.A. Smith, R.L. Kolotkin, P.J. Geiselman, M.A. McVay, E.Z. Oddone, and C.I. Voils.

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