With fasted cardio being extremely popular atm, let us examine the logic behind it to see whether it is as effective as we are led to believe. We will have a look at the available data and then offer some tips to maximize fat burning during your fasted cardio session.
The Popular Premise of performing Fasted Cardio is that your body will tap into stored Fat as an energy source more readily when there are less carbohydrates on offer. Seems to make sense, lets have a look at the key variables to see if this is indeed the case.
Morning Cortisol: Cortisol ideally should be high first thigh in the morning if your body is functioning properly. A Cortisol release in the morning will wake you up and release some fatty acids into your system and traditionally would give your ancestors enough energy to forage some berries or catch a rabbit/fish. If Cortisol is dumping fatty acids into your blood upon waking, then theoretically ramping up the fat burning process with some morning cardio makes sense.
Studies relating directly to this process are eluding us atm, so the following advice is purely my best guess/opinion until more studies arrive. If the body is on maintenance calories or slightly below then the chance of burning muscle for energy during fasted cardio is quite low. If however, you are dragging your butt and are 12 weeks into a contest prep or Summer cut, then Stored Carbohydrates and Fat are lower and the chance of breaking the muscles down to use the Amino acids for energy are higher. Losing muscle is to be avoided and the use of EAA just before Fasted cardio may be of benefit. With the addition of EAA technically the Cardio is now NOT Fasted, but do you want to retain muscle and lose fat OR be a zealot Internet clown stuck in the weeds?
Fat/Carbohydrate/Amino Acid Metabolism: The body is usually using a mixture of all 3 macro nutrients for energy production throughout the day. Here are a few factors that influence what ratio of nutrients will be utilized
· What’s available – If you have just eaten 3 doughnuts then you won’t be tapping into stored fat anytime soon. If your carbohydrate consumption is moderate or lower than usual, then there is a good chance that carbs calories alone won’t be enough and you will tap into some stored fat.
· Type of Exercise – High Intensity exercise tends to rely on carbohydrates as the primary energy source and Amino acids if carbohydrates are low. Steady state Cardio under 65% burns mostly fat as energy source.
· Supplement use – the use of stimulants such as caffeine found in fat burners/pre-workout should help with the release of extra fat into the blood to be processed for energy production.
Essential Amino Acids: have been shown to reduce the cortisol response, basically the body assumes you caught the rabbit, and you don’t need as much cortisol anymore. The obvious question now is won’t the body just use the freshly consumed EAA for energy before it taps into the stored body fat? Again, Studies are rare and I’m going to extrapolate on the limited research to give us a guideline until we get more research.
My guess is that if you are in a depleted state your body was going to break some muscle down to get amino acids for energy along with tapping into stored fat for a Fasted steady state cardio session. By adding in some EAA hopefully muscle is sparred and most of the calories used are coming from fat stores.
Protocol: Here is what I recommend for my clients.
1. Wake up early
2. Drink a glass of water within the first 5-10 min of waking
3. 20 min after waking take a Fat burning product (optional) with 10-15g of Essential Amino Acids
4. 30 min after waking perform Steady State cardio session (heart rate around 65% of YOUR maximum heart rate).
5. For those doing cardio after weight training sessions, take 10-15 grams of EAA after weights, before you start cardio.
The more depleted that your body is, the greater the odds are your body will need those EAAs to preserve muscle while doing cardio. I wish I could just point you to the latest study, however there isn’t one and sometimes on the leading edge we have to experiment and use our best judgment. Happy fat burning
