It’s become common knowledge now with the rise of science-based fitness coaches that spot reducing body fat is not possible, but why is that the case? Before revealing why spot reduction is not possible (without surgery), let’s define the term “spot reducing” first. Simply put, spot reducing is trying to burn body fat off of a specific body part through resistance training. It may involve doing crunches to reduce belly fat or doing shoulder exercises to reduce arm fat. This isn’t possible and it all comes down to basic exercise physiology. Before continuing with this blog post, I would like to source my exercise science class at Fresno State titled ‘Fitness and Wellness’ and the very knowledgeable Dr. Morales and Dr. Coles for providing me with a simple explanation on resistance training and fat oxidation.
Why Resistance Training Does Not (Directly) Burn Body Fat
Resistance training is a short, powerful, and intense form of exercise. This form of exercise typically involves short bursts of effort lasting from around 30 seconds to 2 minutes accounting for the duration of the sets of exercises and discounting the duration of rest periods between sets. The energy systems we use to provide the needed energy for these short bouts of exercise are the ATP-PC system and the anaerobic glycolytic system. Without getting extremely technical with energy metabolism, these systems use glucose, ATP and phosphocreatine as their main source of energy because ATP-PC and glucose are easier and faster to break down for energy than fat. A greater percentage of fat oxidation occurs with lower intensity and longer duration bouts of exercise such as a long walk or leisurely bike ride. As mentioned above, resistance training is a shorter and more intense form of exercise so it requires glucose (AKA sugar) as the main source of energy during training bouts. This is why following a ketogenic diet (eating mostly fats and proteins and hardly any carbohydrates) is not recommended for someone who partakes in high intensity training, including strength training and high-intensity aerobic training, as energy stores for this type of training will be low and will negatively affect your performance. Instead, following a moderate diet that includes all macronutrients will ensure you get the adequate amount of carbohydrates for energy for the body and brain, protein for tissue maintenance and repair, as well as fats for energy and hormonal regulation.
What Actually “Burns” Body Fat
Being in energy imbalance (being in a caloric deficit or consuming less energy than you expend) is what will actually burn body fat in the long run. Body fat is burned from energy stores all over the body and the exact places you store and burn body fat is determined by genetics. Unfortunately, besides getting liposuction, it is not possible to pick and choose where our bodies store and burn body fat. Instead of worrying about where exactly your body burns fat, dedicate yourself to the habits necessary to lose body fat all over and stick to these habits long enough to eventually reach your body fat goal. Follow a moderate caloric deficit, lift weights to get stronger and increase your resting metabolic rate, sleep enough to recover, do cardio to increase your caloric deficit as well as improve heart function, and eat nutritious foods and you are sure to accomplish your fat loss goal!