Risk of overweight and obesity among semivegetarian, lactovegetarian, and vegan women

Am J Clin Nutr. 2005 Jun;81(6):1267-74. doi: 10.1093/ajcn/81.6.1267.


Background: Observational studies suggest that a plant-based diet is inversely related to body mass index (BMI), overweight, and obesity.

Objective: Our objective was to examine the BMI (kg/m(2)) and risk of overweight and obesity of self-defined semivegetarian, lactovegetarian, and vegan women.

Design: Data analyzed in this cross-sectional study were from 55459 healthy women participating in the Swedish Mammography Cohort. Women were asked whether they considered themselves to be omnivores (n = 54257), semivegetarians (n = 960), lactovegetarians (n = 159), or vegans (n = 83), and this question was the main exposure variable in this study. In secondary analyses, we reclassified women as lactovegetarians on the basis of food intakes reported on the food-frequency questionnaire.

Results: The prevalence of overweight or obesity (BMI >/= 25) was 40% among omnivores, 29% among both semivegetarians and vegans, and 25% among lactovegetarians. In multivariate, adjusted logistic regression analyses, self-identified vegans had a significantly lower risk of overweight or obesity [odds ratio (OR) = 0.35; 95% CI: 0.18, 0.69] than did omnivores, as did lactovegetarians (OR = 0.54; 95% CI: 0.35, 0.85) and semivegetarians (OR = 0.52; 95% CI: 0.43, 0.62). Risk of overweight or obesity remained significantly lower among lactovegetarians classified on the basis of the food-frequency questionnaire (OR = 0.48; 95% CI: 0.30, 0.78).

Conclusions: Even if vegetarians consume some animal products, our results suggest that self-identified semivegetarian, lactovegetarian, and vegan women have a lower risk of overweight and obesity than do omnivorous women. The advice to consume more plant foods and less animal products may help individuals control their weight.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anthropometry
  • Cohort Studies
  • Confidence Intervals
  • Cross-Sectional Studies
  • Diet, Vegetarian*
  • Eating
  • Female
  • Humans
  • Linear Models
  • Logistic Models
  • Meat
  • Middle Aged
  • Multivariate Analysis
  • Obesity / epidemiology*
  • Obesity / etiology
  • Obesity / prevention & control
  • Odds Ratio
  • Risk Factors
  • Surveys and Questionnaires
  • Sweden / epidemiology