The association between quitting smoking and weight gain: a systematic review and meta-analysis of prospective cohort studies

Obes Rev. 2015 Oct;16(10):883-901. doi: 10.1111/obr.12304. Epub 2015 Jun 26.


This systematic review and meta-analysis aimed to quantify weight gain after smoking cessation and the difference in weight gain between quitters and continuing smokers. Five electronic databases were searched before January 2015. Population-based prospective cohort studies were included if they recorded the weight change of adult smokers from baseline (before smoking cessation) to follow-up (at least 3 months after cessation). Thirty-five cohort studies were identified, including 63,403 quitters and 388,432 continuing smokers. The mean weight gain was 4.10 kg (95% confidence interval [CI]: 2.69, 5.51) and body mass index (BMI) gain was 1.14 kg m(-2) (95% CI: 0.50, 1.79) among quitters. Compared with continuing smoking, quitting smoking was significantly associated with absolute weight (adjusted mean difference [MD]: 2.61 kg; 95% CI: 1.61, 3.60) and BMI gain (adjusted MD: 0.63 kg m(-2) ; 95% CI: 0.46, 0.80). Subgroup analyses using geographic region found that the difference in weight gain was considerably greater in studies from North America than from Asia. Follow-up length was identified as a source of heterogeneity, such that studies with longer follow-up showed greater difference in weight gain. Effective strategies are needed to encourage smokers to quit irrespective of potential weight gain and to help quitters avoid excess weight gain.

Keywords: Cohort studies; meta-analysis; smoking cessation; weight gain.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Body Mass Index
  • Humans
  • Molecular Sequence Data
  • Obesity / etiology*
  • Obesity / metabolism
  • Obesity / psychology
  • Prospective Studies
  • Smoking / adverse effects*
  • Smoking / metabolism
  • Smoking / psychology
  • Smoking Cessation / psychology*
  • Time Factors
  • Weight Gain

Associated data

  • GENBANK/CD006219