The Fat Burning Zone, Does it Really Cause More Weight Loss?
Weight loss is accomplished by creating a caloric deficit, plain and simple. Calories are a measure of energy. We consume calories in the form of food and expend calories through regular metabolic processes, such as breathing and digesting our food, and exercise. To create a deficit, one needs to eat less calories, and expend more through exercise. The thing to keep in mind is that it doesn’t matter if those calories come from fat or carbohydrates, just that they’re used up.
Our bodies have two options for fuel to use for energy to accomplish the tasks we ask of it. One is sugar, or glucose that is obtained from carbohydrates, the other is fat. Whether our body chooses to primarily use fat or carbohydrates is simply a choice of which fuel it prefers to do the job we are asking it to do.
When at rest, our bodies predominately use a mixture of mostly fat and some carbohydrates; about 60-70% of the energy coming from fat and the remainder from carbohydrates. It is important to remember that without carbohydrates, our bodies do not metabolize fat properly, and release ketones as a byproduct of incomplete fat metabolism, which, in large quantities, can result in a condition called ketoacidosis, which can be ultimately fatal if not reversed in time.
Whether our bodies choose to use more fat or carbohydrates during exercise is dependent upon four factors: intensity and duration of activity, fitness level, and availability of fuel. However, to clarify that exercising in a fat burning zone will not result in increased weight loss; we just need to focus on intensity of exercise and its effect on fuel utilization. Generally speaking, the lower the intensity of an activity, the greater it depends on fat to do the work we ask it to, and that’s where the fat burning zone on the exercise equipment comes in. As the intensity of an activity increases, the body starts to switch over and use more carbohydrates and less fat. However, remember that the more intense the exercise, the more calories are expended over the same duration, and the more likely a caloric deficit resulting in measurable weight loss is achieved.
The take home message here is that our bodies adapt to use the best fuel for the activities we ask it to participate in. However, when it comes to caloric expenditure and weight loss, it is not which fuel our bodies prefer, but how many calories we expend during an exercise bout and that is increased with both increased intensity and duration of activity.
Clinical Exercise Physiologist
Articles don't accept comments on Fitness Inventor but you could ask a question about its contents, if you like.