Want to lose weight? Quit smoking.

NAVARRA, Spain, April 26 (UPI) -- Not only does smoking not make people thinner, it is linked to weight gain, researchers in Spain said.

Lead author Francisco Javier Basterra-Gortari of the University of Navarra said nicotine poisoning was linked to weight gain.

The study, published in Revista Espanola de Cardiologia, found after tracking smokers, non-smokers and those who quit, those who had never smoked put on the least amount of weight over a 4-year period.

The researchers tracked 7,565 people age 50 and older for initial body mass index, being sedentary, physical activity, calorie/fiber intake, snacks between meals and consumption of soda, fast food and alcohol.

People who smoked the most at the beginning of the study and quit smoking during the study period gained the most weight, the study found.

In addition, those who smoked throughout the study also gained more weight during the study period than the non-smokers, Basterra-Gortari said.