Aging and health as a relationship are both largely determined by the level of blood sugar and insulin control. If sugar and insulin are high then you simply age faster. You won’t live as long and here is a BONUS, you will be more prone to chronic disease such as diabetes, heart disease cancer and Alzheimers. And don’t be fooled by the word “sugar”.  Any high carb food that breaks down quickly (glycemic index) is turning into sugar at the speed of light. Here is a short list of foods LOADED with “sugar”: whole wheat bread, crackers, pasta, WHOLE-WHEAT pasta, Dannon yogurt, banana’s, melon, pineapple, granola, breakfast cereal, potato, rice, and the list goes on. So how do we control blood sugar? Number one stop eating it but also we will change our bodies fuel source and abilities by exercising in a fasted (no calories) state.

As Americans we have been coached, taught, and brain washed by our government and our medical academies to eat as much carb as humanly possible. Why? Because it must be healthy right? NO. It’s because it is good for business. We are the biggest grain producer in the world so of course Uncle Sam wants me to eat more of this. Wendell Berry said it best:

People are fed by the food industry, which pays no attention to health,

and are treated by the health industry, which pays no attention to food.

Fasted Exercise

Muscles are responsible for 80% of your blood sugar utilization or disposal. If we can train the muscles to be more efficient at using fat as an alternative fuel to sugar then the rise and fall of glucose swings is greatly reduced. If we train muscles in a fasting state they go on the search for energy sources. Fasting for 12 hours before a workout depletes most of our stored sugar (glycogen) so it now seeks an alternative – FAT!  If we make the muscles perform on a recuring basis we are in essence teaching it how to better use fat. The muscle gets increasing efficient at burning fat and we become metabolically “flexible”. Our bodies can switch fuel source as needed. Our efficiency can double or triple and fat oxidation or “fat burning” dramatically increases. This is adaptation in muscle cells. What’s going on in there?

  • The mitochondria that make energy are stimulated to make more enzymes and improve their output.
  • Our cells start to use broken cell parts, essentially liter within the cell, as fuel. Cleans up efficiency. 
  • Triglycerides (fat) that sits within the muscle cell becomes fuel with greater ease.

Genetic alterations, turning genes off or on, occur during a fast that promote health. Gluttony turns of damaging gene expressions that invite disease. This is commonly referred to as “flipping the switch” as genes are influenced by our lifestyle in both directions, for good and evil. This is so empowering as it puts us in control of which genes we engage.

Exercise in a fasting state is not as hard as you might think. If you gut isn’t digesting food then that energy can be diverted to exercise. Taking in carbohydrates directly reduces the ability to burn fat during exercise. High fat diet intake stimulates fat burning and suppresses carbohydrate utilization so this can make the glycogen stores last longer. Endurance training with a high fat diet stimulates adaptations in muscle cells to facilitate fat oxidation. So cells become better fat burners both at rest and during exercise.

If you train in the morning without eating you are training the muscle to get more efficient. This could help your fat burning even without doing prolonged fasts. In contrast the intake of carbs at any time reduces your ability to burn fat at rest and during exercise. Carb intake shortens life span and health span.

Fasting athletes had less of a problem with blood sugar drop during exercise.

“Flipping the switch” from carb to fat utilization is associated with greater longevity

AMPK is stimulated by exercising in fasted states.  AMPK stimulates mitochondrial biogenesis by stimulating PGC1a.  That is direct antiaging. In simple terms, more energy producing mitochondria that are actually more efficient.

Final point of importance: this is not what I recommend for peak performance. This is a training modality. A tool for longevity. Studies do show that if you are stepping onto a soccer pitch for a game, heading out for a spirited 3-hour bike ride, attempting an athletic adventure where your peak performance is required then this is not the time to go to war in a fasted state. Fasted workouts should be a part of your training process not your competing platform.

I recommend at least one fasted workout per week. This is not necessarily your most intense workout of the week but don't be afraid to step on the gas and go hard. Your goals will dictate how often and how long you do this. If your primary goal is weight loss versus athletic performance then your path will vary but every human endeavor improves when engaging fasted workouts.