This is why people put on weight after quitting smoking

One of the most common side effects associated with quitting cigarettes is weight gain. While people tend to substitute one habit for another or refer to it as an expression of fear, a new study provides some much-needed scientific explanation.

The study, published in the Nature Journal, suggests that the gut microbiome plays a role in the association between smoking cessation and weight gain. However, the mechanisms as to why this happens are not clear.

Scientists developed a variety of tests using mice, exposing them to smoke and then recording their variations in gut bacteria. The initial results showed that mice exposed to cigarette smoke resisted weight gain when they ate a high-fat diet. When the smoke stopped and the mice continued to eat the same food, they put on weight.

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Subsequent studies proved the importance of intestinal bacteria in this situation; Scientists provided the mice with antibiotics that depleted their microbiome and found that this could affect their weight gain. Finally, the scientists transplanted fecal samples from the mice exposed to the smoke into normal mice and found that the normal mice also showed fluctuations in weight.

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The researchers then identified the elements in the microbiome responsible for this change and specifically named dimethylglycine (DMG) and acetylglycine (ACG). By improving and reducing these elements in mice, they found that even mice not exposed to smoke had fluctuations in weight. Healthy mice given DMG supplements gained weight, while healthy mice given ACG supplements lost weight.

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96 human participants also took part in this study, all of which showed similar results to the mice. While this isn’t a complete win when it comes to understanding how smoke affects our stomachs, it is an important first step that could help people understand the effects of cigarettes on gut health, and even some solutions in the future that might encourage people to give up the habit without worrying about the possible side effects.