Research
Energy balance
Former smokers have a significantly higher risk of obesity compared to current smokers, with risk increasing based on the amount and duration of previous smoking, though this risk decreases over time since quitting.
If you have quit smoking, you are at a higher risk of obesity than if you were still smoking, especially if you were a heavy smoker. This risk decreases the longer you have been quit, normalizing after about 30 years. Plan for weight management support when you quit.
GoodSupportsHIGH confidence
Former smokers were more likely to be obese than both current smokers (adjusted OR 1.33 95% CI 1.30-1.37) and never smokers (adjusted OR 1.14 95% CI 1.12-1.15)... Risk of obesity fell with time from quitting. After 30 years, former smokers still had higher risk of obesity than current smokers but the same risk as never smokers.
Why this rating
Large sample size and dose-response analysis strengthen the finding, but cross-sectional design remains a limitation.
Source
Relationship between Smoking and Obesity: A Cross-Sectional Study of 499,504 Middle-Aged Adults in the UK General Population
Shadrach Dare et al. · PLoS ONE · 2015
DOI 10.1371/journal.pone.0123579
cross_sectional · n=499504Cited 375×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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