By Dr. Priyom Bose, Ph.D. Reviewed by Lauren Hardaker Jul 1 2025 A decade-long twin study reveals that an active lifestyle could be the key to managing the growing waistline often seen in people who quit smoking. Study:  Associations of smoking status and leisure-time physical activity with waist circumference change—10-year follow-up among twin adults . Image credit: Krzysztof Winnik/Shutterstock.com A recent International Journal of Obesity study explored the associations of leisure-time