You rely only on your workout to blast belly fat Even if you're a religious gym-goer, it may not be enough to fight middle-age spread. Research shows that people who meet the recommended 150 minutes per week of physical activity are still at increased risk of obesity if they spend the majority of their day sitting. The good news? Research also shows that people who report higher levels of non-exercise activity (such as taking extra trips to the water fountain or doing chores around the house rather than watching TV) have smaller waists than those who are more inactive.