Tobacco withdrawal increases junk food intake: The role of the endogenous opioid system

Background: The aims of this study were to 1) determine whether acute nicotine withdrawal increases the intake of junk food (high in salt, fat, and sugar) and 2) assess whether the endogenous opioid system is involved in junk food intake during nicotine withdrawal using naltrexone as a pharmacological probe. Methods: Smokers were randomly assigned to 24-hr withdrawal from tobacco products (n = 42) or smoking ad libitum (n = 34). A non-smoking group (n = 29) was included. Participants completed two laboratory sessions where a placebo or 50 mg of naltrexone was administered. At the end of each session, participants were given a tray of snack items that differed in high to low energy density and dimensions of salty, sweet, and fat. Selfreported mood and withdrawal measures were collected immediately before the snacks were offered. Generalized linear and logistic models were used to assess the effects of acute smoking withdrawal, drug, and sex on the intake of snack items and self-reported measures. Results: Choice and consumption of food items were impacted by smoking condition (withdrawal > ad lib smoking and non-smokers; p < .05), the opioid blockade (naltrexone < placebo; p < .05), and sex (male > female; p < .05). The effects were evidenced in high sweet and high fat foods. No differences were found in low sweet and fat foods. Conclusions: These findings extend earlier studies indicating impact of tobacco use on appetite, and identify the regulatory influence of the endogenous opioid system on appetite during nicotine withdrawal.