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A randomized clinical trial of a standard versus vegetarian diet for weight loss: the impact of treatment preference

International Journal of Obesity volume 32, pages 166–176 (2008)Cite this article

Abstract

Background:

With obesity rampant, methods to achieve sustained weight loss remain elusive.

Objective:

To compare the long-term weight-loss efficacy of 2 cal and fat-restricted diets, standard (omnivorous) versus lacto–ovo–vegetarian, and to determine the effect of a chosen diet versus an assigned diet.

Design, subjects:

A randomized clinical trial was conducted with 176 adults who were sedentary and overweight (mean body mass index, 34.0 kg/m2). Participants were first randomly assigned to either receive their preferred diet or be assigned to a diet group and second, were given their diet of preference or randomly assigned to a standard weight-loss diet or a lacto–ovo–vegetarian diet. Participants underwent a university-based weight-control program consisting of daily dietary and exercise goals plus 12 months of behavioral counseling followed by a 6-month maintenance phase.

Measurements:

Percentage change in body weight, body mass index, waist circumference, low- and high-density lipoprotein, glucose, insulin and macronutrient intake.

Results:

The program was completed by 132 (75%) of the participants. At 18 months, mean percentage weight loss was greater (P=0.01) in the two groups that were assigned a diet (standard, 8.0% (s.d., 7.8%); vegetarian, 7.9% (s.d., 8.1%)) than in those provided the diet of their choice (standard, 3.9% (s.d., 6.1%); vegetarian, 5.3% (s.d., 6.2%)). No difference was observed in weight loss between the two types of diet. Over the 18-month program, all groups showed significant weight loss.

Conclusions:

Participants assigned to their dietary preference did not have enhanced treatment outcomes. However, all groups lost weight with losses ranging from 4 to 8% at 18 months.

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Acknowledgements

This study was supported by National Institutes of Health grants NIH, NIDDK, no. RO1-DK58631. The conduct of the study was also supported by the Data Management Core of the Center for Research in Chronic Disorders NIH-NINR no. P30-NR03924, the Obesity and Nutrition Research Center NIH-NIDDK no. DK-046204, the Heinz Nutrition Laboratory and the General Clinical Research Center, NIH-NCRR-GCRC no. 5MO1-RR00056 at the University of Pittsburgh. We thank the study participants who graciously shared their time and information with us.

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Authors and Affiliations

  1. Department of Health and Community Systems and the Graduate School of Public Health, Department of Epidemiology, University of Pittsburgh School of Nursing, Pittsburgh, PA, USA

    L E Burke

  2. Department of Health and Community Systems, University of Pittsburgh School of Nursing, Pittsburgh, PA, USA

    M Warziski, M A Styn & E Music

  3. Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA

    A G Hudson

  4. Department of Health and Community Systems and the Graduate School of Public Health, Department of Biostatistics and Department of Epidemiology, University of Pittsburgh School of Nursing, Pittsburgh, PA, USA

    S M Sereika

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  1. L E Burke
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Correspondence to L E Burke.

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Burke, L., Warziski, M., Styn, M. et al. A randomized clinical trial of a standard versus vegetarian diet for weight loss: the impact of treatment preference. Int J Obes 32, 166–176 (2008). https://doi.org/10.1038/sj.ijo.0803706

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