Key takeaways
- Smoking suppresses appetite, leading to lower weight.
- Quitting smoking reveals poor eating habits.
- Improved taste, smell increase food appeal.
- Fear of weight gain deters quitting.
- Nutritional support aids successful quitting attempts.
According to a large-scale cross-sectional study of 80,000 adults, people who smoke tend to have lower body weight and develop poor eating habits that lead to weight gain once they quit.
Why do people who stop smoking gain significant weight? Researchers at Loughborough University and the University of Leicester, UK, may have an answer.
In a paper presented at the European Congress on Obesity (ECO) in Venice, Italy on 12 – 15 May 2024, data from over 80,000 smoking and non-smoking adults (full abstract PDF) suggest that people who smoke have problematic eating habits exacerbated by the absence of nicotine.
The cross-sectional study also suggests that some current smokers used cigarettes to control their appetites and are less likely to snack between meals.
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Data from the large-scale research of over 6,000 currently smoking adults and 77,000 non-smokers between the age of 40 – 44 includes each participant’s sex, socioeconomic status, smoking status, and eating and dietary behaviours.
Smoking as a form of appetite control
Cigarettes contain nicotine which suppresses ghrelin, a hormone that signals hunger.
Chief investigator Dr Scott Willis from Loughborough University, UK, said, “The worry of gaining weight is a common reason for smokers not attempting to quit or being unsuccessful in their attempts to quit smoking.”
According to the study, about 35% of smokers are less likely to eat anything between their meals compared to their non-smoking counterparts. They are also unlikely to eat food as a reward or to alleviate boredom.
Further data from the study also shows that smokers are 8 – 13% less likely to eat sweets between meals and desserts
Poor eating habits and nicotine abstinence
While smokers might have lower weight and lower fat levels, it doesn’t mean they’re truly healthy.
During their quit journey, when reducing or going without nicotine and its appetite suppressing effect, many smokers fall into a weight gain phase due to poor eating and dietary habits developed throughout their years of smoking.
Data from the research suggests that 8% of current smokers are more likely to eat fried food, and about 70% usually add more salt to their meals. About 36% of smokers add more sugar to their food compared to non-smokers.
Men were more likely to add salt and sugar to their meals than women. The study points out this to be due to men being much more likely to adopt unhealthy diets.
One probable reason for more fried food and additional salt and sugar with meals is how chemicals in cigarette smoke dull the senses, especially taste and smell.
Once a motivated smoker starts their quit journey, their sense of taste and smell improves, which may make many foods more attractive. Combined with restored ghrelin levels and poor diet habits, smokers are highly likely to gain additional pounds after quitting.
“Our findings indicate that smoking is associated with eating behaviour patterns consistent with reduced food intake and worse diet quality, characterised by frequent intake of fried food and adding salt and sugar to meals. This could help explain the weight gain commonly observed when people stop smoking,” said Dr Willis.
Weight gain is a deterrent of quitting smoking
Most smokers think twice about quitting smoking or fail in their attempts to do so fearing they will gain weight.
According to lead author Arwa Alruwaili from Loughborough University, the study highlights the importance of nutritional and weight management support for motivated smokers trying to quit.
“This could help to promote more successful quit attempts, and to improve people’s eating habits and the many diseases that are related to both of these major health risks,” Alruwaili said.
The results of the study are observational findings and cannot determine a definite cause-and-effect as to why cigarette smokers tend to gain weight after smoking.