In a perfect world, everyone would work out enough and eat right all the time. What really matters most—dieting or exercise—for losing weight, fighting disease, and boosting overall well-being. Exercise causes the brain to pour out invigorating neurotransmitters like dopamine and norepinephrine, says Patrick O'Connor, Ph.D., an exercise psychologist at the University of Georgia. "If you had to focus on one nutrient that would lower your heart disease risk, it would be omega-3 fatty acids," says William Harris, Ph.D., director of the cardiovascular health research center at the University of South Dakota.

Nearly 10 million American women have diabetes. Achieving a healthy weight through diet and exercise is the strongest defense against the disease, but physical activity has a slight edge. Eating a mostly plant-based diet and exercising regularly remain the gold standard for warding off cancer.

What happenes if you can't work out and you have to sit at home and do nothing, cause you got hurt of taking a box down from the attic or fell off the ladder. And you were in shape and now that you can't do anything for a couple of months.