Your body uses calories as fuel and knowing how this works can make a big difference in how you approach your weight loss program. The body primarily uses fat and carbs for fuel. A small amount of protein is used during exercise, but it's mainly used to repair the muscles after exercise. Depending on the activity you are doing, the ratio of these fuels will shift. A fast paced-running (higher intensity exercise) will rely more on carbs for fuel than fat. That's because the metabolic pathways available to break down carbs for energy are more efficient than the pathways available for fat breakdown. With longer, slower exercise, fat is used more for energy than carbs. When it comes to weight loss, it doesn't matter what type of fuel you use. What matters is how many calories you burn as opposed to how many calories you take in. Just because you're using more fat as energy doesn't mean you're burning more calories, is the bottom line.
Written by Michael Massafra, Head Trainer at Ellis Athletic Center