Alan Aragon and Alwyn Cosgrove have both referred to fasted cardio as "bull*$%!".

I was wondering why people think that doing cardio on an empty stomach is a good idea and what if any science supports the position.

no science.

A lot of people have been doing it for a long time and don't want to stop. Thats all. Science says it's suboptimal, but it's probably not a big deal as long as it's LISS or something similar in intensity.

I'd say like lots of other stuff it depends on the individual, their genetics, conditioning, the rest of their diet, etc.

As I've said before, the only thing I do fasted is eat breakfast.

Of course, I hate LISS in general as it bores me. That factors in, too :D

According to Chris Aceto,who is Jay Cutler's personal nutritionist and also is a regular writer for Muscle & Fitness in the October issue he addresses this same question...

He states positively that fasted cardio works better for fat loss than non-fasted. Especially a.m. fasted.

Alan Aragon and Alwyn Cosgrove have both referred to fasted cardio as "bull*$%!".

I was wondering why people think that doing cardio on an empty stomach is a good idea and what if any science supports the position.

First of all you have to consider the goal. If you aren't interested in fat loss, then it's not clear that there is any benefit whatsoever to any fasted exercise.

If you have a fat loss goal there are lots of ways to go after it. As far as the most efficient way to burn fat Calories, it's the sort of HIIT towards the Tabata end of the spectrum. Now compare that to fasted LISS. There are huge differences in the side effects - fasted LISS does absolutely zero to increase your VO2max and lactate threshold, but Tabata is one of the more effective ways to increase those. But HIIT tends to deplete glycogen, and turn on a hormonal response to exercise. If for some reason you don't want that? Then LISS can make sense.

There can be a perception that fasted LISS is a lot different than nonfasted LISS. That really depends on the idea that when you are fed, you will burn lots of carbs during the LISS. That's really only true if you have a low lactate threshold - which could very well be the case if you don't do any other exercise to maintain a high lactate threshold.

Another important question is duration. If you do a short bout of exercise (say less than five minutes) then you really don't recruit the fat metabolism so much. If you go for more than an hour, the fat burning continues to increase as the carbohydrate burning decreases. Past ninety minutes and you're burning a lot of fat and not a lot of carbs. But the fasted LISS proponents don't expect you to do a long workout to burn fat, they want a shorter workout. In order to get the most fat burn from a short workout, they want blood sugar to be down. They figure that before breakfast is a good time for that.

So there are lots of pieces of context that influence whether there is a role for fasted LISS in your program.

First of all you have to consider the goal. If you aren't interested in fat loss, then it's not clear that there is any benefit whatsoever to any fasted exercise.

If you have a fat loss goal there are lots of ways to go after it. As far as the most efficient way to burn fat Calories, it's the sort of HIIT towards the Tabata end of the spectrum. Now compare that to fasted LISS. There are huge differences in the side effects - fasted LISS does absolutely zero to increase your VO2max and lactate threshold, but Tabata is one of the more effective ways to increase those. But HIIT tends to deplete glycogen, and turn on a hormonal response to exercise. If for some reason you don't want that? Then LISS can make sense.

There can be a perception that fasted LISS is a lot different than nonfasted LISS. That really depends on the idea that when you are fed, you will burn lots of carbs during the LISS. That's really only true if you have a low lactate threshold - which could very well be the case if you don't do any other exercise to maintain a high lactate threshold.

Another important question is duration. If you do a short bout of exercise (say less than five minutes) then you really don't recruit the fat metabolism so much. If you go for more than an hour, the fat burning continues to increase as the carbohydrate burning decreases. Past ninety minutes and you're burning a lot of fat and not a lot of carbs. But the fasted LISS proponents don't expect you to do a long workout to burn fat, they want a shorter workout. In order to get the most fat burn from a short workout, they want blood sugar to be down. They figure that before breakfast is a good time for that.

So there are lots of pieces of context that influence whether there is a role for fasted LISS in your program.

Can I be the first to say, WHAT?!!!

Acronym this, acronym that. I'm friggin' lost man. :bang:

Can I be the first to say, WHAT?!!!

Acronym this, acronym that. I'm friggin' lost man. :bang:

Zen knows his stuff. Just read the stickies and keep reading this board and it will eventually all make sense. :read:

Enter the terms in Google or the search engine here. These internets tubes iz fantasticks !!!!!

Can I be the first to say, WHAT?!!!

Acronym this, acronym that. I'm friggin' lost man. :bang:

Heheh. :read: LISS = Low Intensity Steady State. HIIT = High Intensity Interval Training. They're the two main types of cardio.

Examples of LISS are jogging, a bike ride, and swimming laps. Usually you do LISS for half an hour to an hour at a time, at a fairly steady pace, and at low to moderate intensity.

HIIT is kinda the opposite of LISS: you put 100% effort for as long as you can, then rest for a minute or two, then go 100% again, over and over. The point there is to go so hard that you can't go for more than 30 seconds or so without feeling like you're going to collapse, so you rest, and then do it again. The intensity is so high that you should be wasted after 20 minutes of this; if you're not, you're not doing it hard enough!

I guess it depends on the individual and their goals, but I've had the best success doing fasted A.M. LISS along with carb-cycling. HIIT doesn't work nearly as well for me. Your mileage will vary.

Zen knows his stuff. Just read the stickies and keep reading this board and it will eventually all make sense. :read:

Enter the terms in Google or the search engine here. These internets tubes iz fantasticks !!!!!

Heheh. :read: LISS = Low Intensity Steady State. HIIT = High Intensity Interval Training. They're the two main types of cardio.

Examples of LISS are jogging, a bike ride, and swimming laps. Usually you do LISS for half an hour to an hour at a time, at a fairly steady pace, and at low to moderate intensity.

HIIT is kinda the opposite of LISS: you put 100% effort for as long as you can, then rest for a minute or two, then go 100% again, over and over. The point there is to go so hard that you can't go for more than 30 seconds or so without feeling like you're going to collapse, so you rest, and then do it again. The intensity is so high that you should be wasted after 20 minutes of this; if you're not, you're not doing it hard enough!

Thanks guys!

My hijack is over. :tu:

I was wondering why people think that doing cardio on an empty stomach is a good idea and what if any science supports the position.

Because there are people who have experienced results using it, plain and simple. Does that mean that they wouldn't have had the same results if they used HIIT, or maybe some other higher intensity steady state? Maybe, maybe not.

But for some, it definitely works. For me, it really doesn't matter if science says that it's suboptimal, for a couple reasons.

1) The science of fitness still has a long way to go. Things that are discovered today may be proven otherwise tomorrow. Does this mean that science isn't usefull, definitely not. But I take most studies with a grain of salt, we still have a long ways to go in understanding the human body.

2) Who cares if HIIT is 15% more efficient than LISS if you don't like doing HIIT but don't mind doing LISS? The MOST important thing is doing something consistently. Overanalyzing everything (while fun :) ) is fine and all, but getting out and doing it is 90% of the battle.

According to Chris Aceto,who is Jay Cutler's personal nutritionist and also is a regular writer for Muscle & Fitness in the October issue he addresses this same question...

He states positively that fasted cardio works better for fat loss than non-fasted. Especially a.m. fasted.

So? There are tons of other experts saying exactly the opposite.

To the majority of us, the difference would be negligible either way. Probably less than 2% I'd bet assuming equal cardio work (LISS for both).

Using my body as a research I can say I agree with Zen. I've done LISS cardio everyday since about July and my VO2 has not changed. The resistance I need to get withing my specific heart range has changed drastically, but not my VO2. So I think it depends on which one is better and for what purposes. They both have pluses and minuses.

I don't necessarily agree that it doesn't matter which one you do. If you want a higher VO2 then I don't think that LISS is the way to go. Even though I think there are plenty of people on the site who don't even do cardio and their VO2 is pretty good. No cardio, cardio, LISS, HITT. Depends on what you goal is.

If you could care less about VO2 then I can see how doing either one doesn't really matter.

Alan Aragon and Alwyn Cosgrove have both referred to fasted cardio as "bull*$%!".

I was wondering why people think that doing cardio on an empty stomach is a good idea and what if any science supports the position.

Venuto and Swolecat reccomend it. And who can argue with their results and the people they've helped.

I think that different programs are sturctured to use different types of cardios. Obviously whatt Aragon and Cosgrove use is not sturctured for LISS.

If you could care less about VO2 then I can see how doing either one doesn't really matter.

:nod:

Just curious, is there anyone out there advocating LISS for building VO2max? I've only heard that it's good for burning fat.

2) Who cares if HIIT is 15% more efficient than LISS

It's a lot more than 15% mode efficient at burning fat Calories. If you are in good shape it's more like twice as efficient or better, plus, it burns a higher ratio of fat to carb Calories.

Just curious, is there anyone out there advocating LISS for building VO2max? I've only heard that it's good for burning fat.

Yes. If you are doing the modern approach to endurance training, you use a lot of interval work, but there is still a component of long steady state work. It's longer duration than what most people do LISS for fat burning only. But the very long LISS workouts for endurance athletes are used to expand the mitochondrial population. That and sometimes rehab are the only athletic uses of LISS I am aware of.

Alan Aragon and Alwyn Cosgrove have both referred to fasted cardio as "bull*$%!".

I was wondering why people think that doing cardio on an empty stomach is a good idea and what if any science supports the position.

Yea but Tom Venuto and Layne Norton finds anything other than fasted cardio should be considered recreational....Different ppl have different theories...In general just go with how you react...I personally used fasted cardio for my initial 50 lb loss in 3 months, but I know others that fared well doing it after their weight lifting session

Yea but Tom Venuto and Layne Norton finds anything other than fasted cardio should be considered recreational....Different ppl have different theories...In general just go with how you react...I personally used fasted cardio for my initial 50 lb loss in 3 months, but I know others that fared well doing it after their weight lifting session
When did Layne say that?

Mannishboy....here's what Chris Aceto says in his article:-

"Doing cardio on an empty stomach (that doesn't include the 5-10 grams of whey protein you should take in immediately beforehand) is great for fatburning as well--first thing in the morning before you eat breakfast is a good time to do it. Hormones play a large role in fat-burning---specifically Insulin, the dominant hormone that can inhibit the breakdown of bodyfat when it's released into the bloodstream after the consumption of carbohydrate.When there's a lack of carbs in the body, Insulin levels remain low, which maximizes the release of fatburning hormones.When you wake up in the morning, your carb levels will probably be at their lowest of the day, setting the stage for a fat-shedding cardio session."

I realize there are only two schools of thought on the Internet... "Yes" and "No way" :lol:

Mannishboy....here's what Chris Aceto says in his article:-

"Insulin, the dominant hormone that can inhibit the breakdown of bodyfat when it's released into the bloodstream after the consumption of carbohydrate.When there's a lack of carbs in the body, Insulin levels remain low, which maximizes the release of fatburning hormones.When you wake up in the morning, your carb levels will probably be at their lowest of the day, setting the stage for a fat-shedding cardio session."


Keep in mind that intense exercise suppresses insulin and depletes carbs. If you use HIIT to burn your carbs off, it gets to a similar starting point.

People have traditionally burned fat with LISS, HIIT, and things like barbell complexes. Studies of 24-hour metabolism tend to show that when you do exercise that burns more fat than carbs, the body adapts to burn more carbs the rest of the day, and when you do exercise that burns more carbs, the body adapts to burn more fat the rest of the day, with the net result being that what you burn during exercise doesn't have a huge influence on the whole-day metabolism.

The thing that differentiates these various Calorie burning strategies is usually the fitness "side effects".

When we get down to very lean people, then things get somewhat different, because fat is essentially burned at a rate proportional to how much fat you have. If you don't get lean, then you don't really have to do all this sharp pencil work to figure out how to burn fat - just maintain a high lactate threshold and burn a lot of Calories. If you get really lean, then you run into the problem of figuring out how to burn the small amount of fat you have left.

what about doing 30 minutes of HIIT followed directly with 30 minutes of LISS? that is what i have started doing since when i need a workout at the house. i hope on the exercise bike and pedal my ass off, literally, while playing some xbox. is there something to be said for doing both or should i just stick to one or the other?

what about doing 30 minutes of HIIT followed directly with 30 minutes of LISS? that is what i have started doing since when i need a workout at the house. i hope on the exercise bike and pedal my ass off, literally, while playing some xbox. is there something to be said for doing both or should i just stick to one or the other?

I think 30 minutes of HIIT is probably a bit much for most people to truly put the proper effort into. Not that the average trainee can't do interval work for that period of time, but they might not be hitting the true "high" part of the equation. Some can, though.

However, I've seen several coaches talk about doing HIIT for 16-20 minutes, resting for 5-10 minutes, then doing some LISS as an advanced technique when nothing else works (not to recommend to do all the time). The theory is that HIIT starts releasing the fat into the system, then after a brief rest, you do some LISS to burn the serum lipids for fuel.

Does it work as theorized? *shrug* I suspect if you are cutting from 8% to 6% it might help a bit, but for most of us it's not a big deal.

Studies of 24-hour metabolism tend to show that when you do exercise that burns more fat than carbs, the body adapts to burn more carbs the rest of the day, and when you do exercise that burns more carbs, the body adapts to burn more fat the rest of the day, with the net result being that what you burn during exercise doesn't have a huge influence on the whole-day metabolism.

What does that do in regards to timing carbs Zen? I.E. does that long steady state work that burns more fat than carbs (LISS) tend to promote increased carb burning? If so could I finally start eating baked potatoes again?:drool:

I've done cardio fast and non-fasted. My results have been EXACTLY the same. It doesn't matter. It's whatever you prefer.

I've done cardio fast and non-fasted. My results have been EXACTLY the same. It doesn't matter. It's whatever you prefer.
It might not matter to you. :)

It might not matter to you. :)

Like I said, it's whatever you prefer. But it remains the same, there is no scientific proof that it benefits someone more if they do cardio fasted. At this point, it's all about preference.

What does that do in regards to timing carbs Zen? I.E. does that long steady state work that burns more fat than carbs (LISS) tend to promote increased carb burning? If so could I finally start eating baked potatoes again?:drool:

Nutrient timing is a game that works as well as your understanding of what your body is actually doing. You get a lot of advice which is based on the presumption of a starting state. For example the idea that you are at a low point for carbs when you get up in the morning is not true for someone who eats the way I do (I carb load overnight pretty often). My low point for carbs is usually right after my workout.

That being said, burning more fat during exercise does tend to increase carb metabolism during rest. So one strategy would be to do LISS so you can eat the potato. In fact just a couple days ago, I did LISS so I could eat a donut.

But It's usually more efficient to use high intensity exercise to burn Calories so you can eat what you want. If you deplete glycogen, and then eat the carbs, a good part of the carbs you eat go for glycogen replenishment.

One way to work out with a high carbohydrate diet it to go for long hard workouts that deplete glycogen as often as possible. Then you are OK for loading the carbs the night before. Like my brother the powerlifter told me why he does so much cardio: "I like to eat."

Like I said, it's whatever you prefer. But it remains the same, there is no scientific proof that it benefits someone more if they do cardio fasted. At this point, it's all about preference.
You said it's whatever you prefer, but you also said it doesn't matter. I'm just making sure that it's said that it doesn't matter to you. To a lot of people it matters a whole lot, because for some people a fasted session may mean muscle loss or a lack of intensity or extreme boredom and frustration (which is where preference comes into play a bit, and yes, preference has a lot to do with it, I agree completely with you there).

You said it's whatever you prefer, but you also said it doesn't matter. I'm just making sure that it's said that it doesn't matter to you. To a lot of people it matters a whole lot, because for some people a fasted session may mean muscle loss or a lack of intensity or extreme boredom and frustration (which is where preference comes into play a bit, and yes, preference has a lot to do with it, I agree completely with you there).

Agreed. But, the original question was which is better, fasted or non-fasted cardio? The question wasn't asking preference, it was asking which is better for fat loss. For fat loss, again, it doesn't matter. You will not lose any more fat fasted than if you did it non-fasted. When it comes to preference, it matters 100%. When it comes to fat loss, it matters 0% (That is assuming one is working hard and not bored).

what about doing 30 minutes of HIIT followed directly with 30 minutes of LISS? that is what i have started doing since when i need a workout at the house. i hope on the exercise bike and pedal my ass off, literally, while playing some xbox. is there something to be said for doing both or should i just stick to one or the other?


I know Cosgrove does this with some of his clients.. but not 30 min of HIIT more like 15 minutes followed by 30 to 45 minutes of LISS. I think he got the idea from Lyle MacDonald if I remember correctly.

After a HIIT session triglyceride levels in the blood increase dramatically indicating that fat stores have been mobilized so the next step is to burn all that off with the LISS.

thefitcast.com has a great interview with Cosgrove where he talks a bit about this..

Im my experience, if I'm truly going all out and doing HIIT as cardio, there is no way I have the energy for LISS after. You should be pretty spent after a HIIT session. That's why it's referred to as high intensity.

thefitcast.com has a great interview with Cosgrove where he talks a bit about this..


We should have a thread on fitness geek podcasts. I'm addicted :) I have 4 or 5 in Juice that I listen to.

Im my experience, if I'm truly going all out and doing HIIT as cardio, there is no way I have the energy for LISS after. You should be pretty spent after a HIIT session. That's why it's referred to as high intensity.

And that's why the second part is after a 10 minute rest and is called "low" intensity :D

Presently I do LISS in a fasted state, first thing in the morning because of what I read from Venuto. It made sense to me. Perhaps it makes no difference but I'm willing to do it even if the benefit is small. At present, I am very overweight. Perhaps I should state the obvious, after reading through the thread I realize that If I attempted the type of HITT we use to do in high school track and cross country (early '80s) I'd be laid up for weeks with injuries. I am, however, looking forward to the time when I reach my goal fitness level and can put the hammer down with some heavy duty interval training. I remember from high school that nothing lowered my times in the 800 meters like interval training (we puked after many a workout). For the present, however, I'll have to stick to the treadmill and the heart rate monitor.