Nicotine and Hunger: Why Smoking Actually Makes You Want to Eat

We often think of nicotine as something that kills your appetite. While it is true that long term smoking can lead to weight loss, some people find that they actually feel a strange surge of hunger right after a cigarette. In our recent study, we explored this "paradoxical hunger" and discovered that nicotine interferes with the body's hormonal signals for fullness.

The Big Question

We wanted to understand why acute nicotine intake—meaning a single dose—causes a temporary increase in feeding behavior. Specifically, we set out to see if nicotine changes the levels of hormones that control our appetite and if these changes are different for those who are already dependent on nicotine compared to those who are not.

Exploring the Hunger Hormones

To find the answer, we studied rats that had become dependent on nicotine through daily exposure and compared them to a non dependent group. We gave them a single injection of nicotine and monitored how much they ate immediately afterward. We also analyzed their blood to look for changes in several key "hunger hormones," including:

• Insulin: Manages blood sugar levels.

• Leptin: Signals to the brain that you have enough energy stored.

• Ghrelin: Known as the hunger hormone because it tells you when to eat.

• Glucagon: Helps maintain blood sugar and is known to reduce appetite.

What We Discovered

Our findings revealed that nicotine sends a "false hunger" signal to the body by disrupting our hormonal balance:

• Hunger in the Dependent: We found that a single dose of nicotine caused a significant increase in eating, but only in the rats that were already dependent on nicotine. Non dependent rats actually ate less, which fits the traditional view of nicotine as an appetite suppressant.

• The Glucagon Drop: In dependent rats, nicotine caused a sharp and sudden decrease in glucagon, the hormone that normally helps us feel full. We believe this drop is what triggers the immediate urge to eat.

• Long Term Imbalance: We confirmed that chronic, long term nicotine use keeps other hormones like insulin and leptin at higher levels than normal, which can eventually lead to metabolic issues like type 2 diabetes.

Why It Matters

This research matters because it helps explain one of the biggest hurdles people face when trying to quit smoking: weight gain. We have shown that nicotine dependency creates a cycle where the body loses its ability to accurately signal fullness.

By understanding that the "fullness hormone" glucagon is being suppressed, we can look for new ways to help people manage their appetite during recovery. We believe that targeting these specific hormonal pathways could lead to better treatments that support both nicotine cessation and metabolic health.

Reference: Shankar, K., Ramborger, J., Bonnet-Zahedi, S., Carrette, L.L.G., & George, O. (2024). Acute nicotine intake increases feeding behavior through decreasing glucagon signaling in dependent male and female rats. Hormones and Behavior, 159, 105447. https://doi.org/10.1016/j.yhbeh.2024.105447