Fasted cardio simply means performing cardiovascular activity with no source of immediate food energy. When we eat food, there is a glucose response in the blood which means a presence of energy, the glucose is used to fuel our bodies cells. No matter what, glucose/glycogen is the very last chemical change that occurs from our food metabolism. When someone says “burn fat” this is a simple expression used to describe the process by which body fat i.e adipose tissue was taken, the fatty acids are broken down through a series of chemical processes until it gets to glucose in which glucose (glycogen) can be used to enter our cells, which is what we use for energy. At the end of the day ALL food is energy, but carbs digest directly into glucose which is why they are the “most ready to use form of energy”, since protein and fats do not digest directly into glucose, they need to go through a longer process which EVENTUALLY leads to glucose.
This is another reason why when you have not eaten much food all day, and start to feel low mood and lethargic, your brain is only wants CARBS. This is because carbs will quickly top up glucose vs. having to go through the more energy taxing process of digesting protein. Another reason as to why people will binge on pasta vs. binge on chicken breast…how many people do you know binge on a bowl of chicken breast? I’ll wait. Long story short…ALL food is energy. All food will raise your blood sugars, thats why all food has calories because calories are the way we indicate how much energy is in X food item. I digress…back to fasted cardio. IF we are performing cardiovascular activity i.e. energy burning/calorie utilizing exercise on an empty stomach or without a presence of food energy, then our metabolism and digestive systems will encourage glucose sitting in our liver to be burned for energy. When the liver has depleted as much glucose/stored energy it is comfortable with, it will shift to our fat stores. The adipose tissue is metabolized through a series of digestive reactions until it becomes glucose, so it can then be converted into glycogen so it can enter our cells, and then it gets converted back into glucose so it can be used as energy. It’s kind of weird why glucose must be converted into glycogen before it can enter the cell, but you can think of our cell walls being swanky, stuck up country clubs that demand a tie and khakis as the dress code or no entry. The cell makes glucose conform before it can be accepted, like a sorority or fraternity type vibe ya know?
Here are 2 simple ways you can implement fasted cardio into your week:
- In the AM as soon as possible from when you wake-up: Our metabolisms are still revving while we are sleeping which means energy was being burned and used. You do not stop burning when you are sleeping!!! Hi are you dead? I hope not. When we wake up 5-8hours later, we are in a depleted state. Depletion means depleted of glucose/energy, i.e. fasted. 4-5x per week wake up perform fasted morning cardio. Wake up, have a glass of water, an espresso (no sugar), bundle up and speed walk for 20-25mins. Make sure you have good shoes. If you get shin splints, avoid inclined speed walking, switch to something else for a bit. If you have access to gym equipment, the stair master is ideal pushing through the glutes every step. FYI the elliptical is the worst choice and has been studied to be least effective for fat burn. After cardio, eat your breakfast!! You are not only depleted from sleep, but have further depleted yourself from the cardio. It is negligent, and also more damaging on your hormone health avoid fuelling up with good wholesome (home made) calories after exercise. You have not eaten since the night before, you MUST eat to fuel your body, stop making it run on a reserve tank. A car runs out of gas, imagine if humans did as well? We would have a bunch of stalled bodies on the sidewalks, offices, malls, cars, ALL OVER THE PLACE if we worked like the fuel in our car. Always remember, eat to grow your muscles, more muscle means a faster resting metabolic rate so that will help burn the fat. The 20-25minute cardio burst helps the entire process along, it’s not the ONLY variable.
- Post-weight workout: Make sure your weight training session is purposeful and not a kumbaya walk in the park. Your mission should be muscle glycogen depletion, make sense? Glycogen is muscles glucose, and glycogen is what helps our muscle fibers contract. Our body will fill up our muscles with glycogen (if you are eating well enough), and as you weight train and push to dig deep and use your entire muscle bellies fibers, then you are depleting them of their glycogen. When your muscles deplete of glycogen, they are topped back up by glucose. Glucose must be converted into glycogen so it can be transported across muscles cells, and then it gets converted back into glucose to be used for energy. If you are depleting yourself during your weights workout then you are technically creating a fasted and depleted state. Steady state or HIIT, 4-5x per week for 15-30minutes, preferably on the stair master. However, if you are NOT working that hard, NOT lifting to your true potential, chatting, and essentially f***ing around during your weight training then you are not depleting your muscles, which means you are not creating as a depleted or fasted state as you could. You need to lift heavy (which is relative to ability) and work hard at getting stronger and getting your muscle bellies bigger.
Studies also show significantly improved gut health, metabolism, and hormone response when someone regularly performs fasted cardio. Fasted cardio does not mean you have to do it for 1hour, 7 days a week for it to be effective. Waking up and going for a brisk walk can be enjoyable, maintainable, and good for mental health. Not only this, but as gut health improves, cravings substantially subside. However, the most significant factor to improved gut health is overall better digestion, and the better you digest, utilize, and excrete your food, the healthier and more efficient your system will become.
Remember, I did not say perform fasted cardio 7x per week for 1-2hours, no no no. I believe cardio should be kept to a time you can commit to regularly, it should not be seen as a daunting and horrifying task. Get up off of your ass, give your brain a burst of feel good hormones first thing in the morning for 20-25 minutes, 4-5x per week (not even everyday…), help improve your gut health as a bonus, and then get to the rest of your healthy eating and weight lifting routine. Fasted cardio is not like “THE holy grail to weight loss” but I also strongly disagree with know-it-all fitness professionals who try to PROVE fasted cardio is not BETTER or more SUPERIOR than general cardio. By coming out and saying “don’t waste your time doing fasted cardio because its not better” or “fasted cardio is a BAD IDEA” in my opinion is not only negligent for the average person in the population, but it’s also making the assumption the average person out there is absolutely 100% on top of their cardio regime. The average person most certainly IS NOT debating whether they should do fasted cardio or not, they are debating whether they should do cardio AT ALL!!!! By arguing what form of cardio is more superior and trying to dump on the other form is basically spoon-feeding all the lazy people an excuse to not get up and start a healthier routine. Is it reaaaaaallllllllyyyy going to be a terrible thing to wake up, and get your blood pumping? Is 20-25minutes walk 4-5x per week going to DESTROY your gains and your soul? Oh pleeeeease. How about instead of saying fasted cardio eats all your muscle and ruins all of your strength gains, we talk about how to eat properly so that does not happen. We talk about why it is important to eat so you can grow your muscles? How about we educate more woman on why it is important to weight train? How about there is SOOO much other work and information that should be focused on other than arguing what cardio is BETTER?! Maybe don’t provide the average non-athletic student/office/desk population sitting 6-8hours an excuse to avoid cardio….
Personally, after a wicked hard weight training session at the gym I feel completely toasted post-weights. I would then skip cardio in general….so NO cardio at all. This is why I do it fasted, because I know myself, and although it is harder to wake up and get into that groove, I will at least complete more cardio sessions fasted, vs. post-workout. Also, again, its 4-5x per WEEK, not an hour every single day. Do your cardio for health, vitality, and longevity.
At the end of the day, if you want to change your body and what you look like then you are going to have to eat super well, weight train with a purpose and a plan, do your cardio (where-ever that may be), and repeat for minimum 12 weeks.