We've all seen the table or graph posted on the treadmill at that gym that talks about the "fat-burning zone." In this post, we'll discuss why it's known as the fat-burning zone and why it may not be your weight loss fix. The title comes from the type of energy used by your body during a particular intensity of exercise. Many researchers have demonstrated the body's use of fat for fuel during lower-intensity exercise. Conversely, carbohydrates are used during more intense bouts of exercise.

One would think: burn fat, lose weight. So why is this method not helping people shed the weight? It has to do with what your body does after exercise, particularly when you eat. We've all heard the analogy of food as fuel for our bodies. When you exercise in the fat-burning zone, most of your carbohydrate stores remain full. When we replenish energy by eating a snack or meal post exercise, those macronutrients (fat, carbohydrate, protein) are absorbed by your body. When your carbohydrate stores are full, the carbs you eat have nowhere to go unless they are used immediately. Instead, they end up getting converted and stored as fat.

There's also the question of calories burned during exercise. Let's pretend that you can somehow eat the exact amount of food to keep your body in a state of homeostasis. Even then, because fat-burning exercise is lower-intensity it burns fewer calories than higher-intensity exercise. Caloric consumption and expenditure as we know are one variable related to your weight.

Moral of the story: if you want to lose weight with your exercise, opt for higher-intensity routines. That's not to say that you shouldn't do any low-intensity exercise. And certainly not to say that you shouldn't eat after a workout. But there is a misconception that this low-intensity method is preferred for weight loss. The truth is higher-intensity, more calorie burning exercise is the way to go.

All that said, I do not advocate that this is what you should strive for. First, weight loss is still less understood than we would like it to be, with many variables impacting your weight - so simply burning more calories may not get you what you want. Second, there is a growing body of research suggesting that being overweight is not the cause of many of the diseases of affluence we face today (like heart disease), but instead it is our generally more sedentary lifestyle. Finally, any amount and type of exercise is better than none, so for those of you just starting out or getting back into it, focus on finding something you enjoy that gets you moving.

In good health,

Francesco