Time it takes: 30 minutes
Nibbling an extra 100 calories a day will pack on 10 pounds in a year. Doing moderate exercise for 30 minutes a day will prevent that gain - and save you money. Obese Americans spend 26% more out of pocket on health care than normal-weight workers, according to a study in Health Affairs. They also take nearly twice as many prescriptions and earn $1.42 less per hour.