That is a good question that doesn’t have a simple answer. In order to lose weight, a person has to have a calorie deficit. In other words, a person has to burn more calories than are consumed. Some studies have shown that when the calorie deficit is equal, diet alone and exercise alone can both produce similar weight and body fat reductions.
To lose a pound of body fat, one needs to burn 3,500 more calories than are eaten. With a daily deficit of 500 calories, a person could lose a pound of fat in a week. Studies show that making better food choices and eating smaller portions can easily reduce calorie intake by 500 calories a day. Burning an extra 500 calories through exercise can be more difficult. You would need to do the following activities for at least one hour to burn 500 calories: rowing, running (11.5 minute mile), ice skating, cross-country skiing, or walking up stairs. A combination of calorie restriction plus exercise seems to work best for most people for weight loss and maintenance. Exercise has the added benefit of increasing good cholesterol, increasing muscle sensitivity to insulin, protecting against bone loss, and reducing stress.
