Creating Weight-Loss
Weight loss is achieved by creating a negative caloric balance in your body. You need to eat fewer calories than you burn through exercise and metabolic processes. Your body will then turn to stored energy or body fat to fuel itself and your body weight will decrease. According to Dr. Len Kravitz, assistant professor of exercise at the University of New Mexico, research shows that significant weight loss is created by moderate to vigorous exercise and not low intensity exercise.
Fuel Contribution
When you exercise, your body needs to fuel itself from stores of carbohydrates and fat. It is a mix of fuel types and not just one or the other. The contribution percentages are what varies depending on the intensity or effort of exercise. When you exercise at a lower intensity, it is burning a higher percentage of fat and lower percentage of carbohydrates. As your intensity increases, this shifts so that you burn more carbohydrates and less fat, according to the National Strength and Conditioning Association.
Intensity and Caloric Burn
In theory, low-intensity exercise does sound like the answer because you are burning a higher percentage of calories from fat. However, it is calories in versus calories out that determines weight loss not where it comes from. Higher intensity exercise burns more calories so contributes to better weight loss results. Consider that you might burn 100 calories during a 20 minute, low-intensity walk. It is possible that 60 calories are from fat and 40 are from carbohydrates. Now increase this to a 20 minute, high-intensity run and you may burn 200 calories. If only 40 percent is from fat, you have burned 80 fat calories compared to 60 at low-intensity exercise.
Exercise Recommendations
To lose a significant amount of weight, which is defined as 5 percent or more of your total body weight, the American College of Sports Medicine recommends an accumulation of 225 to 420 minutes of moderate to vigorous exercise each week. This should be a combination of cardiovascular and resistance exercise for the most health and weight-loss benefit. Choose activities that you enjoy as well as challenge you to stay motivated.
Considerations
None of this means that low-intensity exercise is bad. If you are new to exercise or have a chronic medical condition, it might be the best choice for you. Discuss limitations with your doctor so you have guidelines to follow. Low-intensity exercise is also a good way to let your body recover from higher levels of physical activity or a way to ease back in after a break. Listen to your body and adjust your exercise intensity accordingly.