Fasting… This is a term that I do not throw out very loosely. I feel that the majority have a misconception of the benefits fasting can yield, and they wind up confusing their total body weight decreases with progress. If not done properly, fasting alone can cause body proteins – like muscle tissue – to breakdown for energy purposes. Adding exercises to the equation further enhances the need for energy, thereby increasing the amount of protein breakdown.

What I want to talk about here is how to take advantage of the benefits of being in a fasted state to optimize the lipolysis process (fat metabolism). I have talked in other posts about the importance of keeping heart rate at a level of 60-70% max HR in order to maximize oxygen uptake and fatty acid breakdown. Since we know how to stimulate lipolysis thru low-level aerobics, how can we further enhance that process? We can thru fasted cardio.

Studies have shown that if low-level aerobic activities are performed after the body has fasted for a period of 12-16 hrs, 80-90% of the total calories expended will come from fatty acids. The key to keeping the body in an oxidative pathway is to focus on HR. There is no magic speed or physical level of exertion that one can use to gauge the oxidative potential. HR is the true indicator of gauging level of intensity. 60-70% of max HR will engage the oxidative pathways, with 60% yielding the greatest potential. Max HR = (Age – 220).

Now we know how to engage the processes during activity, but what about ergogenic aides? My favorite is caffeine. Caffeine is a stimulant that elicits a number of physiological and psychological effects in the body. Studies have proven caffeine to enhance endurance by stimulating the fat cells to release their fatty acids, thereby slowing glycogen use, and my attenuating the perception of fatigue. To reap these benefits, the appropriate dosage would be approximately 200mg 15-30 min prior to activity. This amount can be found in approximately 10-12 oz of coffee depending on the brew, or in one (1) NoDoz tablet. I am a fan of NoDoz because I’m a lazy fucker and the tablet is quicker than brewing a pot of coffee and doesn’t stain the teeth or leave a smell on the breath. Lol

Now the question generally comes to light about the preservation of lean body mass during such an activity. Two primary considerations here would be to focus on engaging the oxidative (aerobic) pathway throughout the activity. See my post on “metabolic continuum” to gain a better understanding of how intensity dictates the energy pathway and the respective fuel source(s). Secondly, would be dietary considerations to aide in the preservation of lean body mass.

Because glucose and liver glycogen must be replenished to provide for the daily activities, it would make sense to ingest carbs post workout. This will of course pull you out of a fasting state, but that’s ok. The focus was to use fasting metabolism to enhance the burning of fats. Research suggests that when incorporating low-level or steady state aerobic activity, the contributions towards energy expenditures take place primarily during the activity and subside shortly thereafter. But what if we could defy these findings with a lil stimulation of another process or two? This is where the nutritional aspects come into play.

I’ve talked about how proteins will become the fuel source for synthesizing glucose when glucose is in short supply. I have also talked about the difference between whey and casein protein. I wanna go a bit deeper into that by introducing the thermic effect of food (TEF).

When a person eats, the GI tract muscles speed up their rhythmic contractions, the cells that manufacture and secrete digestive juices begin their tasks, and some nutrients are absorbed by active transport. This acceleration of activity requires energy and produces heat, which is expressed as TEF. The TEF is proportional to the food energy (calories) taken in and is usually estimated at 10% of calorie intake. Thus a person consuming 2000 kcal will expend approx. 200 kcal thru TEF. These factors are influenced by meal sizes and frequency. The more frequent the meals, the greater chance the body will be able to utilize the nutrients for energy purposes. In general, the TEF is greater for high-protein foods than high-fat foods. Likewise, it is greater for complex carbs than simple carbs.

So, the idea would be to use a dietary protein source for two main reasons. 1) to provide proteins thru nutrition for glucose synthesis, thereby preserving lean tissue. 2) to increase the TEF during digestion, thereby increasing the energy expenditures post exercise. Adding to this is the effort the body must go thru in order to convert proteins’ amino acids into glucose. This process actually expends energy to make energy. We are actually making our body work to meet its energy demands.

Because the need for immediate proteins post low-level cardio is virtually non-existent, casein would be the ideal choice. The amino acid chain comprising casein is much more complex than that of whey protein. As a result the composing amino acids will sort of trickle into the blood stream to provide a steady flow over the course. The body will use these amino acids for the synthesis of glucose, thereby sparing muscle tissue.

This casein supplement can be consumed either pre-workout or post-workout. My preference is pre-workout. I like to ensure that amino acids are present because oxidative metabolism takes a few minutes to kick in. Yes, this introduction of nutrients will begin transitioning the body out of fasting state, but the glucose will still be unavailable at this point. As a result, the body must then begin converting the dietary proteins into glucose for the activity. This enhances the energy expenditure thru thermogenesis. Post-workout, I like to consume ONLY complex carbs. Once again, the digestive system must work a bit harder to breakdown the carb chain to yield glucose. This in turn yields greater thermogenesis. Additionally, the complex carbs will sort of trickle into the blood stream to provide a steady flow of glucose. This will make the fuel source available while keeping insulin at bay. Thru this glucose regulation, we are further able to take advantage of fatty acid metabolism. Once sufficient glucose is available, the metabolism of fatty acids will begin to fade.

This is my spin on these processes. Go check out lordoftheoctagon's thread on LISS and HIIT. He further adds to this with LIIS, plus expounds on the HIIT principle. Very good read IMO.

http://www.eroids.com/forum/training-nutrition-diet/weight-loss/hiit-v-liss

References:

This was strictly pulled out of my ass along with a few cross references.