Myths Under The Microscope: The Low Intensity Fat Burning Zone & Fasted Cardio

[papagunz]

Alan, this may have been covered already, but I'm curious. Have you read Lyle McDonald's stubborn fat solution, and if so, what do you think?

I'm specifically referring to the low intensity protocol with Yohimbine, Caffeine, and Tyrosine recommended fasted or well after a meal. Do you personally think that there is a link between the effectiveness of stubborn fat (a2 rich) removal and fasted cardio? Or, do you think a high dose of stims first thing in the morning may antagonize the **** out of cortisol and possibly be counter productive in the long run?

Thanks.

[sensei101]

Eat less calories than you burn - keep this up for a few months. Cardio type is secondary to that. Very distantly secondary.

But after all is said and done.What is the main way to target fat loss then..I know that HIIT and low intensity cardio all have thier ups but whats the most prodcutive route?

[Bioteknik]

But after all is said and done.What is the main way to target fat loss then..I know that HIIT and low intensity cardio all have thier ups but whats the most prodcutive route?

calories in << calories out. burn more than you're consuming, whichever way works best for you.

[alan aragon]

Alan, this may have been covered already, but I'm curious. Have you read Lyle McDonald's stubborn fat solution, and if so, what do you think?

I'm specifically referring to the low intensity protocol with Yohimbine, Caffeine, and Tyrosine recommended fasted or well after a meal. Do you personally think that there is a link between the effectiveness of stubborn fat (a2 rich) removal and fasted cardio? Or, do you think a high dose of stims first thing in the morning may antagonize the **** out of cortisol and possibly be counter productive in the long run?

Thanks.

The removal of stubborn fat via fasted cardio + stims is sound in theory. However, I've prepped competitors just fine with fed cardio at higher intensities & low intensities (fasted), and both methods seem to work equally well for fat loss. BTW, high-dose stims 1st thing in the morning would actually raise cortisol. In the end, maintaining a deficit over a prolonged period is gonna be the most effective component by a long shot. The rest of the little tweaks (ie fasted vs fed low-intensity cardio) make negligible difference given equal macronutrition. PS - I don't do cardio, so I don't worry about this ****

[papagunz]

The removal of stubborn fat via fasted cardio + stims is sound in theory. However, I've prepped competitors just fine with fed cardio at higher intensities & low intensities (fasted), and both methods seem to work equally well for fat loss. BTW, high-dose stims 1st thing in the morning would actually raise cortisol. In the end, maintaining a deficit over a prolonged period is gonna be the most effective component by a long shot. The rest of the little tweaks (ie fasted vs fed low-intensity cardio) make negligible difference given equal macronutrition. PS - I don't do cardio, so I don't worry about this ****

I meant to say agonize cortisol. Oh well, typos ftw.

Thanks for the reply Alan.

[alan aragon]

I meant to say agonize cortisol. Oh well, typos ftw.

Thanks for the reply Alan.

No probs dude. And I figured there was a chance of an unintentional switch-up there.

[W8isGR8]

Biggest problem I had with fed cardio was that after making sure I had proper pre/post workout nutrition....I ended up eating just as many calories as I was burning with the cardio, so I never saw any change, lol

[jgabaldon22]

this was awesome, i have had this way of thinking for a long time now, but you said it man, the overall of these articles hit right on overall imo. great job!

[RippedFibers]

Wow, im great I found this, i was planning on doing fasted cardio in the morning, but instead im just going to do it in the evening.

[ElMariachi]

Wow, im great I found this, i was planning on doing fasted cardio in the morning, but instead im just going to do it in the evening.

I just do my cardio first thing in the morning because I've found that it boosts my energy levels and gets me going the rest of the day. Not sure how much more beneficial it is in the morning, but it has become pretty convenient for me.


Get up, take some BCAA's, do 15-25 minutes of high intensity cardio, shower, eat breakfast....etc.

[dEntremont]

I just finished going through this thread and just like your pre and post-workout nutrition thread it has really helped me Alan.

I started HIIT on Tuesday and I'm doing it again tonight. I like it so much more than doing straight low intensity cardio.

I can't wait to see what my results are like in the coming months having combined the knowledge I have gained from reading both your threads. I may look good on that Christmas Caribbean cruise after all!

I still can't believe you give us this stuff for free!

[starsg]

Great article. Thanks

[Maverick777]

So in other worss this is a wild goose chase and they have no damn idea which causes more fat loss

[MAKUA NUI]

Myths Under The Microscope: The Low Intensity Fat Burning Zone & Fasted Cardio

By Alan Aragon


INTRODUCTION

Why do natural bodybuilding contests for the most part look like swim meets minus the pool?

The obvious answer is the relative absence of anabolic and androgenic drugs that enable “enhanced” athletes to hold on to considerably more muscle under prolonged metabolic stress than natural pre-contest trainees. The other part of the answer is that naturals as a group tend to undermine their efforts by copying the training and nutritional practices of their pharmacologically advantaged brethren.

I wrote this review in the hopes of slowly but surely prying open some minds (including my own) by bringing the facts to light. Sometimes concepts can’t be sufficiently conveyed through cyber debates, where emotionally-driven flexing and posturing for the public take priority over honest, objective, and thorough examination of the evidence. I’ll take a look at the hard data, as well as the theoretical extrapolations involved with this highly misunderstood topic.

Warning: This is gonna be lengthy, so save this reading for when you can really sit down and buckle up. I highly encourage you to tread slowly and carefully through the material. For you skimmers out there, I provided summaries of the key research points.


THE “FAT BURNING ZONE” ON TRIAL

Substrate Utilization 101: Origin of the myth

Dietary variables aside, the body’s proportional use of fat for fuel during exercise is dependent upon training intensity. The lower the intensity, the greater the proportion of stored fat is used for fuel. The higher the intensity, the greater proportional use of glycogen and/or the phos****en system. But this is where the misunderstanding begins. Common sense should make it obvious that although I’m burning a greater proportion of stored fat typing this sentence, Getting up and sprinting would have a greater impact on fat reduction despite its lesser proportional use of fat to power the increased intensity. Alas, sufficient investigation of the intensity threshold of maximal net fat oxidation has been done. In what’s perhaps the best designed trial of its kind, Achten & Jeukendrup found peak fat oxidation to occur during exercise at 63% VO2 max. This peak level got progressively less beyond that point, and was minimal at 82% VO2 max, near the lactate threshold of 87% [1].

Misunderstanding is perpetuated in fitness circles

It has been widely misconstrued that a greater net amount of fat is burned through lower to moderate intensity work, regardless of study duration and endpoints assessed. In addition the confusion of net fat oxidation with proportional fat oxidation, the postexercise period is critically overlooked. No distinction is ever made between during-exercise fat oxidation, recovery period fat oxidation, total fat oxidation by the end of a 24-hr period, and most importantly, a longer term of several weeks.. Thus, the superiority of lower intensity cardio continues to be touted over the more rigorous stuff that takes half the time to do. Fortunately, we have enough research data to gain a clear understanding. Let’s dig in.


DISSECTING THE RESEARCH

Mixed study protocols + mixed results = plenty of mixed-up bodybuilders

As with all research involving applied physiology, the highly mixed set of results is due to a wide variation of study designs in terms subject profile, dietary manipulation, energetic balance, and actual intensities used. Nevertheless, the body of exercise-induced fat oxidation research can be easily deciphered by stratifying it into 3 subgroups: Acute effect (during exercise & immediately after), 24-hr effect, & chronic effect (results over several weeks).

Acute effects spawn ideas for further research

In addition to measuring fat oxidation during exercise, most acute effect trials look at fat oxidation at the 3 to 6 hr mark postexercise [2]. Fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation tends to be higher in high-intensity treatments. For example, Phelain’s team compared fat oxidation in at 3hrs postexercise of 75% VO2 max versus the same kcals burned at 50% [3]. Fat oxidation was insignificantly higher during exercise for the 50% group, but was significantly higher for the 75% group 3 hours postexercise. Lee’s team compared, in college males, the thermogenic and lipolytic effects of exercise pre-fueled with milk + glucose on high versus low-intensity training [4]. Predictably, pre-exercise intake of the milk/glucose solution increased excess postexercise oxygen consumption (EPOC, aka residual thermogenesis) significantly more than the fasted control group in both cases. The high-intensity treatment had more fat oxidation during the recovery period than the low intensity treatment. This implicates pre-fueled high-intensity training’s potential role in optimizing fat reduction while simultaneously setting the stage for quicker recovery.

24-hr effects come closer to reality

You can call it Murphy’s Law, but the promise of greater fat oxidation seen during and in the early postexercise periods of lower intensity cardio disappears when the effects are measured over 24 hours. Melanson’s research team was perhaps the first to break the redundancy of studies that only compared effects within a few hours postexercise [5]. In a design involving an even mix of lean, healthy men & women aged 20-45, identical caloric expenditures of 40% VO2 max was compared with 70% VO2 max. Result? No difference in net fat oxidation between the low & high-intensity groups at the 24 hr mark.

Saris & Schrauwen conducted a similar study on obese males using a high-intensity interval protocol versus a low-intensity linear one [6]. There was no difference in fat oxidation between high & low intensity treatments at 24 hrs. In addition, the high-intensity group actually maintained a lower respiratory quotient in postexercise. This means that their fat oxidation was higher than the low-intensity group the rest of the day following the training bout, thus the evening out the end results at 24 hrs.

Chronic effects come even closer

Long-term/Chronic effect studies are the true tests of whatever hints and clues we might get from acute studies. The results of trials carried out over several weeks have obvious validity advantages over shorter ones. They also afford the opportunity to measure changes in body composition, versus mere substrate use proximal to exercise. The common thread running through these trials is that when caloric expenditure during exercise is matched, negligible fat loss differences are seen. The fact relevant to bodybuilding is that high-intensity groups either gain or maintain LBM, whereas the low-intensity groups tend to lose lean mass, hence the high intensity groups experience less net losses in weight [7-9].

The body of research strongly favors high-intensity interval training (HIIT) for both fat loss and lean mass gain/maintenance, even across a broad range of study populations [9-12]. A memorable example of this is work by Tremblay’s team, observing the effect of 20 weeks of HIIT versus endurance training (ET) on young adults [9]. When energy expenditure between groups was corrected, HIIT group showed a whopping 9 times the fat loss as the ET group. In the HIIT group, biopsies showed an increase of glycolytic enzymes, as well as an increase of 3-hydroxyacyl coenzyme A dehydrogenase (HADH) activity, a marker of fat oxidation. Researchers concluded that the metabolic adaptations in muscle in response to HIIT favor the process of fat oxidation. The mechanisms for these results are still under investigation, but they’re centered around residual thermic and lipolytic effects mediated by enzymatic, morphologic, and beta-adrenergic adaptations in muscle. Linear/steady state comparisons of the 2 types tends to find no difference, except for better cardiovascular fitness gains in the high-intensity groups [13].

Summing up the research findings

• In acute trials, fat oxidation during exercise tends to be higher in low-intensity treatments, but postexercise fat oxidation and/or energy expenditure tends to be higher in high-intensity treatments.
• Fed subjects consistently experience a greater thermic effect postexercise in both intensity ranges.
• In 24-hr trials, there is no difference in fat oxidation between the 2 types, pointing to a delayed rise in fat oxidation in the high-intensity groups which evens out the field.
• In long-term studies, both linear high-intensity and HIIT training is superior to lower intensities on the whole for maintaining and/or increasing cardiovascular fitness & lean mass, and are at least as effective, and according to some research, far better at reducing bodyfat.

Awesome piece and for people like me for a long time who was doin' the low intensity cardio and not seeing any results until I stop and started doing HIIT. The weight came flying off and there's no looking back now.

But, by doing HIIT on the regular do you eventully hit a plateau?

[seancovell]

For my last pre-competition cardio sessions, I used a combination of HIIT training and Low Intensity cardio on the recumbent bike. Like most discourses in the world, things are rarely black and white. HIIT serves its purpose well for increasing metabolism and stimulating protein synthesis. Low intensity cardio is great for recovery purposes. (After a hard leg workout, the cardiovascular exercise will flush some of the lactic acid buildup.) This allows for faster recovery time and I think helped add some size to my legs because of the repetitive motion.

Keep in mind, long duration cardio is not a great idea for those looking to retain muscle mass(unless you're on significant amounts of steroids). Glycogen stores in muscle tissue and liver will be sapped. With low carb diets, which are common pre-contest, energy levels and attitude will suffer. I kept most of my sessions to under 30 minutes. If you are lifting intensely, this will also help increase metabolism. Remember, physical appearance is mostly dietary habits and genetics. Hard work in the weight room and with cardiovascular exercise obviously helps hone in on definition, but either HIIT or low intense long duration cardio will be nullified by lack of discipline in dieting.

All in all, HIIT is my preferred method for cardio most of the time. I have clients on various Interval Training programs and the results are absolutely phenomenal.

[dzimmerman123]

Nice post, good factual information.

[Iaskwhynot]

Good post

[HalleluYAH]

The removal of stubborn fat via fasted cardio + stims is sound in theory. However, I've prepped competitors just fine with fed cardio at higher intensities & low intensities (fasted), and both methods seem to work equally well for fat loss. BTW, high-dose stims 1st thing in the morning would actually raise cortisol. In the end, maintaining a deficit over a prolonged period is gonna be the most effective component by a long shot. The rest of the little tweaks (ie fasted vs fed low-intensity cardio) make negligible difference given equal macronutrition. PS - I don't do cardio, so I don't worry about this ****

Alan et al, this gets me thinking. More specifically, when discussing the role increases stim intake can have on lipolysis... iy seems be prudent to also consider the role increased norepenephrine presence has on glucose uptake into adipocytes.

it would seem in theory, anyone using high stim intake to increase lipolysis should simultanesouly have a diet aimed at increased insulin sensitivity - i.e. carb cycling, lcd, etc.

can anyone elaborate on this thought process?

[Iron Rain]

Nice.

__________________
http://germanvolumetraining.blogspot.com
All about German Volume Training AKA Ten Sets Method

[Bioteknik]

Alan et al, this gets me thinking. More specifically, when discussing the role increases stim intake can have on lipolysis... iy seems be prudent to also consider the role increased norepenephrine presence has on glucose uptake into adipocytes.

it would seem in theory, anyone using high stim intake to increase lipolysis should simultanesouly have a diet aimed at increased insulin sensitivity - i.e. carb cycling, lcd, etc.

can anyone elaborate on this thought process?

Lyle McD has it in one of his free articles on his site that specifically states that stubborn fat (like the kind targeted by using the stims) is best taken off with a lower carb approach.

[Arenas1]

very awesome read, and i agree with what was stated at the end. Take your own personal preferance and just do the damn thing. in a world, and especially a country where the big mac and the burrito have replaced solid wholesome meals and where childhood obesity is on the rise, Cardio is a must! must! must! To all you BBer's out there, amatuer, pro, natural and juicers alike. I thank you for inspiration.

Research is a must and opinions must be heeded and taken with a grain of salt.

[sicklinez]

Thanks for another informative piece alan! I have just got back into the gym, after a 6 month break, today's day 4 of week 3. Quick question, how can I figure out my v02max? How does it correlate with my hr?

[xxno1xx]

yeah i agree its good data but im in red

[chenrko420]

thanks for the info. you are always unbiased with your research.

[gonloft]

calories in << calories out. burn more than you're consuming, whichever way works best for you.

exactly!

btw, nice thread!

[papagunz]

it would seem in theory, anyone using high stim intake to increase lipolysis should simultanesouly have a diet aimed at increased insulin sensitivity - i.e. carb cycling, lcd, etc.

can anyone elaborate on this thought process?

One would figure that any sane diet plan is going to result in increased insulin sensitity. To what degree, however, will carb cycling/lcd versus an approximate 40P/30C/30F (balanced diet, basically) increase insulin sensivity, I have no idea.

Someone else mentioned Lyle's book (which I have), and it seems fasted cardio + Y/Caff/Tyr and fasted cardio on a low carb diet (sans stims) seem to be on par. However, the stims PLUS the LCD is most effective, apparently.

Let us also not forget that yohimbine increases insulin response to carbohydrates. Does anyone have an idea how long after ingestion this effect lasts? Also, is the moa A2 antagonism in pancreatic cells that are responsible for insulin production?

[harlan100]

It has to be said that its FACT that the infomation in this post is fantasitc

[Mayra85]

No cuestion Thanks for the post

[Mayra85]

I got all the ansers here.

I am starting with all this and l was looking for a site like this.

Thanks for the thread

[Edelmania]

hmm seems like 20 mins or so of HIIT like an hour and half after a meal would be good O.o?