Optimal HR Zone for Burning Fat

[Splash]

Hello all.

(This is a general fitness question and may not specifically relate to bike riding but instead can relate to any form of exercise... So, power meters are not part of this query...)

I recently read that too high HR zone does not burn fat. Why is this?

I always thought that a higher heart rate would be better for burning off fat because of the higher intensity required to sustain this higher heart rate...

Which heart rate zone is best for burning fat and why?


Note to ALL - please DO NOT contribute / post on this thread if you cannot be specific to the thread title.


Splash

[echappist]

Hello all.

I recently read that too high HR zone does not burn fat as much as Lower heart rate zones.

Why is this?


rate of energy oxidation. Exercise is essentially the burning of energy (which requires oxygen); higher the intensity, faster the energy burning required. If we are just straight up burning things, we get CO2 and H2O; however, your body requires intermediates between the initial oxidation of energy source (either fat or sugar) and the final release of waste as Co2 and H2O.

HR is an indicator of rate of oxygen consumption. Rate of lipid oxidation is a lot slower than rate of sugar oxidation, as the former requires quite a fewer more steps to become suitable for energy utilization whereas the latter does not (this assumes steady state, aerobic efforts). At high enough intensity levels, energy supplied from oxidizing fat alone can no longer meet demand, thus requiring the oxidizing of sugars in your body. At even higher intensity, even the oxidization of sugar is no longer enough to keep up with demand, and you essentially end up partially oxidizing sugar. The byproduct of the partial oxidation is pyruvate, which your body converts into lactate. You can do this type of energy utilization for only so long before too much lactate accumulates, forcing you to drop the intensity. When the intensity has dropped sufficiently, the body converts lactate back into pyruvate, and pyruvate then gets further utilized for energy via aerobic process.

I always thought that a higher heart rate would be better for burning off fat because of the higher intensity required to sustain this higher heart rate...

Which heart rate zone is best for burning fat and why?

Splash

Fat burning zone is red herring. The following chart shows you why. At the end of the day, the colloquial fat burning (i.e. losing weight) is mostly dependent on energy in/energy out, and the more energy you burn, the more weight you lose.

The fat burning zone (~55 % VO2max) is so termed because this is the zone at which energy derived from fat burning per se (and not contribution of fat burned as percent of total energy burned) is the greatest. It's a middling endurance intensity, which can be kept up for 4-5 hours. However, in term of energy burned/time spent, it's about 2/3 of what can be sustained for 40-50 minutes. If you want to maximize the portion that is burned as fat, you actually go less than 55% VO2max.

Takeaway message is that at the end of the day, it's (primarily) how much energy burned that matters, not how much fat burned per se that matters

https://www.researchgate.net/profile/Tim_Constantin/publication/258337810/figure/fig2/AS:202604043870222@1425315977000/Energy-expenditure-and-fuel-selection-during-cycling-exercise-at-75-of-VO2max-Adapted.png

[Splash]

Thanks for the detailed reply.

What % of VO2max (and over what duration of time) would you advise for maximising the portion of energy that is burned as fat?

For weight reduction driven exercise, is the optimal time of day to exercise - for maximising the portion of energy that is burned as fat - deemed to be after awaking from sleep AND before any food calorie/energy intake?

I have read that this is the best time because your body has been working throughout the night processing any ingested food from the day before and so any energy burned (during exercise after waking up) will be mostly from existing body fat storage and not much from any food calorie/energy. Is this correct? Something to do with insulin levels...?

What does "other fat sources" represent on that bar chart you provided?



Splash

[John H.]

What is your end goal?

Are you looking to improve your cycling, or reduce your body mass?

I bet you will say both- but is one more important?

It is not as simple as locking in to a "magic" zone and burning way more fat.

For cycling fitness- a balanced program that is polarized with all zones (at the right times and in the correct does works best).

For weight loss- the bottom line is that you need to eat less than you burn over a long period of time.

[SoCalSteve]

What is your end goal?

Are you looking to improve your cycling, or reduce your body mass?

I bet you will say both- but is one more important?

It is not as simple as locking in to a "magic" zone and burning way more fat.

For cycling fitness- a balanced program that is polarized with all zones (at the right times and in the correct does works best).

For weight loss- the bottom line is that you need to eat less than you burn over a long period of time.

Congratulations! You just wrote the shortest, most effective weight loss book ever!

I hope it’s a best seller and makes The NY Times best sellers list.

One last piece of weight loss advice ( Like anyone asked for my advice )...it’s 80%/20% in terms of importance. Guess what is 80%. Eating less or exercise?

[Splash]

Thanks Guys.

Yes. I am very much aware of the eating less, exercising more line.....Can we perhaps move past that for the purpose of this thread.........??

This is not about cycling per se, that is why I specified this in the OP. I have put on weight from minimal activity over last few months. So I want to lose weight before I get serious in cycling again. Cycling will assist me losing this weight and so wil many other things like diet and other forms of exercise. So, for this moment, my end goal is to lose 15kg. Improving Cycling technique, power, etc will come later...for the purpose of this thread, I want to learn more about Identifying optimal HR zones and nothing more.

If you want to contribute to this thread, can I please ask that you be specific to the OP and thread title and not derail the thread by deviating away.

Thank you


Splash

[floxy1]

In my experience V02 intervals are optimal for burning fat.

[Gummee]

So, for this moment, my end goal is to lose 15kg. Improving Cycling technique, power, etc will come later...for the purpose of this thread, I want to learn more about Identifying optimal HR zones and nothing more.
As has been said: there's no 'magic bullet' for burning fat.

Your best bet to lose that 15kg is ride, ride, ride. Keep the eating at the same level you're at now, and the weight will come off.

IME the more you do, the faster things happen.

M
The guy that's lost 20kg riding bicycles

[Splash]

Thanks Flo x y 1

Can you possibly elaborate on how you have used VO2 intervals for burning fat in your experience?

Durations, %levels of VO2, etc?


Gumme e - re-read post #6.


Splash

[regularguy412]

Disclaimer: I'm not an Exercise Physiologist.

I would add to the aforementioned, that some consideration needs to be given to the subject's age. As I'm nearing the big SIX-OH, I find that riding more and eating same amount doesn't quite cut it like it used to. This is from the guy that took 6 years off the bike, gained 80 lbs and then lost 70 of it,,, all that between the ages of 40 and 50. So it can be done, but as I get a little older, I find that using the same formula to become fitter/lose weight doesn't quite work like it used to.

So now I'm just trying to hold steady,, even though I've put about 25 of that 70 back on. Work,,, ya know,, sux. :bike:

Mike in AR:beer:

[John H.]

It is a low number- like 60-70% of VO2 max hr.
Every step up in zone burns less fat, more glycogen.

But again, higher zones burn more total calories during the workout and keep metabolism at a higher level after a ride- so it is not as simple as what you are asking.

To simplify this- find an eating plan that allows you to lose weight. Then add back in enough calories to fuel whatever riding you are doing.

[Splash]

Thanks John H.

Interesting information regarding HR zones.

Does fat burn more efficiently when exercising after a long period of sleep and no food ingestion?


Splash

[John H.]

Not more efficiently- but you may be able to pull it off if intensity is low-ish and ride does not get too long.

It works for some but it may not be the best way to train.

Like I have said, and others have chimed in- there is no "magic bullet".

Thanks John H.

Interesting information regarding HR zones.

Does fat burn more efficiently when exercising after a long period of sleep and no food ingestion?


Splash

[weisan]

To simplify this- find an eating plan that allows you to lose weight. Then add back in enough calories to fuel whatever riding you are doing.

I got the first part down (lost about 7 pounds in 10 days), still trying to figure out the second part. I skipped dinner yesterday and my last meal was at 2:30 pm. At today's group ride, I basically ran out of fuel at the 50 mile mark despite eating regularly during the ride. Apparently, I went too much into a deficit that normal breakfast and on-bike feeding couldn't make up for it fast enough.

This is all new territory to me. I have never consciously engaged in a weight loss regimen until recently because weight was never a major issue for me on top of the regular exercise that I do. However, I realized as I get older that it's becoming harder to keep this up just through exercise, I actually need to watch my intake as well. Over the last 10 days I have cut my daily calorie intake by 20-30% and the effect is almost immediate. I also started doing upper body workouts. My goal other than weight loss is to see that whole middle section goes down, way down.

[sdrides]

At the end of the day, the colloquial fat burning (i.e. losing weight) is mostly dependent on energy in/energy out, and the more energy you burn, the more weight you lose.

That's the basic idea. Early AM "fasted cardio," as the bodybuilders call it, does burn more fat and more calories because of the biochemistry involved, and because it essentially puts your body at a deficit to start the day from which you will have to work harder to recover unless you can take naps at work. That said, it also depletes the muscles themselves more, so I would say that from an overall performance standpoint it's not as great as it might seem. If you just want to look good then give it a shot, but honestly cycling doesn't cut it for looks! If cycling performance matters, then it's better to eat before you ride.

Mainly the best way to burn fat is to ride your bike below lactate threshold for as long as possible, eat healthy, and drink plenty of water. Since you're probably short on time during the day, throw in a couple interval sessions here or there to increase the deficit and have some fun.

Final note: don't conflate body weight with body composition. Working out in a dehydrated and/or fasted state will often give the appearance of weight loss that same day (both in the mirror and on the scale), but I would argue that it's not the same thing as the genuine weight loss you're seeking, which is actually a change in body composition. Water weighs 8 lbs. per gallon...

[11.4]

Thanks Guys.

Yes. I am very much aware of the eating less, exercising more line.....Can we perhaps move past that for the purpose of this thread.........??

This is not about cycling per se, that is why I specified this in the OP. I have put on weight from minimal activity over last few months. So I want to lose weight before I get serious in cycling again. Cycling will assist me losing this weight and so wil many other things like diet and other forms of exercise. So, for this moment, my end goal is to lose 15kg. Improving Cycling technique, power, etc will come later...for the purpose of this thread, I want to learn more about Identifying optimal HR zones and nothing more.

If you want to contribute to this thread, can I please ask that you be specific to the OP and thread title and not derail the thread by deviating away.

Thank you


Splash

What people are trying to say here is that the basic question is flawed. It isn't founded in the best exercise research. So if there isn't a preferential fat-metabolism modality to draw upon, you're down to the basics of calories in, calories out.

Nobody is trying to redirect this thread. They're just trying to address the legitimacy of the question.

[SoCalSteve]

What people are trying to say here is that the basic question is flawed. It isn't founded in the best exercise research. So if there isn't a preferential fat-metabolism modality to draw upon, you're down to the basics of calories in, calories out.

Nobody is trying to redirect this thread. They're just trying to address the legitimacy of the question.

Thanks Lane!

I think the simple answer is just that...the less calories you put in your body, the more weight you will lose. Again, it’s a very simple equation. You can spin it all you want...but in the end, eat less and exercise more.

[echappist]

Thanks for the detailed reply.

What % of VO2max (and over what duration of time) would you advise for maximising the portion of energy that is burned as fat?

For weight reduction driven exercise, is the optimal time of day to exercise - for maximising the portion of energy that is burned as fat - deemed to be after awaking from sleep AND before any food calorie/energy intake?

I have read that this is the best time because your body has been working throughout the night processing any ingested food from the day before and so any energy burned (during exercise after waking up) will be mostly from existing body fat storage and not much from any food calorie/energy. Is this correct? Something to do with insulin levels...?

What does "other fat sources" represent on that bar chart you provided?



Splash

as others said, don't worry about fat burning per se, and instead worry about energy expended. A good 70-80% of weight loss is based on calorie in calorie out.

The other thing is, if you need to do a 4-5 hour ride, the majority of your effort will be at ~55-65% of VO2max anyways. If you have just 1.5 hours and you want to get fast, you'll be doing intervals at 95% VO2max for 30 minutes. Let the target dictate your training, and have the type of riding you do come out as a result of that.

That said, fasted riding might benefit you (though it might deplete muscle mass). The thing here is that if you wake up early and manage a 1.5-hour ride at 60% while fasted, it would be more likely for you to skip out on calories and not feel the effect. However, it's still a calories in/calories out thing at the end. The other thing is that it'd be very hard to go at higher intensity on a full stomach. At the end of the day, it's a balancing act. When i need to do a long ride, i try to go early and not eat for the first 90 minutes for calorie management. But if I want to hit a performance target, i'll eat something.

[Splash]

Thanks Echappist.

What does "other fat sources" represent on that bar chart you provided earlier in this thread?

You also stated earlier in this thread that a value less than 55% VO2max is better for Maximising the portion of energy that is burned for fat. What is this value?


Splash

[echappist]

The other source of fat is triglycerides in muscles

as for "You also stated earlier in this thread that a value less than 55% VO2max is better for Maximising the portion of energy that is burned for fat. What is this value?"

I'm not sure myself, but you can see a trend in that graph showing where fat burned as portion of total energy burned would be a bit less than 55% VO2max.

But I think in reality, you should ask yourself the following (i know you don't have a power meter, but it's highly relevant as watt produced leads to calories burned.

Say your VO2max is 360W. You have 90 minutes to ride. Which would burn more energy (and lead to greater weight loss, or allow you to eat more).

Would this be doing 200W for 90 minutes (during which ~60% of the energy comes from fat), or would this be doing 270W for 90 minutes (during which ~30% of the energy comes from fat)?

The energy expenditure in the former is 200 Joule/s (that's definition of a watt) x 3600 s/hr x 1.5 hr = 1080 kJ, of which 648 is from fat. In the latter, it would be 1458 kJ, of which 437 is from fat. When it comes to physiology, the generation of a Joule (as energy output) requires about 4.1 Joules (as energy input), and as 4.18 Joule = 1 calorie, 1080 kJ generate ~1080 kCal (that's the unit on nutrition labels) burned. The latter would allow you to eat ~400kCal more food without gaining any weight

[Splash]

Fantastic stuff! Wow!

Time to invest in a power meter...thinking of getting the new Vector 3 when they are released...

Do you have any other similar charts like the one you provided earlier outlining fat burned/energy/level of effort, etc..?

Splash

[Splash]

As glycogen is fuel for your muscles and used for energy production, optimizing glycogen stores is important.

How does one know when these glycogen stores are optimised?

In what ways are these stores optimised?



Splash

[Louis]

Wow - all this time, I've been riding my bike primarily because it's fun.

Splash, good luck with your fitness program. It doesn't sound like this is what you're looking for, but just the same, I'd suggest you not try to over-think it. Just ride the bike. If you want to be faster, then ride harder. If you want to loose weight, then ride longer.

Edit: If you really want to loose weight, then try running instead of cycling. Calorie-wise riding a bike is super-efficient. Running is much less efficient. So assuming your knees can take the beating, in the same amount of time you'll burn way more calories running than you will cycling.

[ripvanrando]

180-age for most people.

180-age-10 for out of condition

180-age+5 for fit individuals

https://philmaffetone.com/what-is-the-maffetone-method/

[ripvanrando]

As glycogen is fuel for your muscles and used for energy production, optimizing glycogen stores is important.

How does one know when these glycogen stores are optimised?

In what ways are these stores optimised?



Splash

You have to burn fat to lose it. Constantly filling your glycogen stores will raise insulin levels and store MORE fat and actually work against you


Just go for long rides before eating breakfast. Only drink water. Skip the post ride carb gulps. Eat your regular diet. Do not increase consumption. 15 Kg can be lost in 2-3 months of diligent effort but it won't be easy.

GL

[echappist]

Fantastic stuff! Wow!

Time to invest in a power meter...thinking of getting the new Vector 3 when they are released...

Do you have any other similar charts like the one you provided earlier outlining fat burned/energy/level of effort, etc..?

Splash
unfortunately no other charts

As glycogen is fuel for your muscles and used for energy production, optimizing glycogen stores is important.

How does one know when these glycogen stores are optimised?

In what ways are these stores optimised?



Splash

Apologies as I don't know.

I think key here is to step back and think about what you want to get out of this. Better performance? Leaner physique? A mix of both?

Good nutrition will also help to make this easier. Vegetables and fibers make you satiated, and at the end of the day, discipline with food (with allowance for weekly mulligans) is the way to go

Powermeters are good as a calorie expenditure device, but they are much more than just that. You'll want to be sure you would be okay with looking at loads of data, etc. Just a few other thoughts

Wow - all this time, I've been riding my bike primarily because it's fun.

Splash, good luck with your fitness program. It doesn't sound like this is what you're looking for, but just the same, I'd suggest you not try to over-think it. Just ride the bike. If you want to be faster, then ride harder. If you want to loose weight, then ride longer.

Edit: If you really want to loose weight, then try running instead of cycling. Calorie-wise riding a bike is super-efficient. Running is much less efficient. So assuming your knees can take the beating, in the same amount of time you'll burn way more calories running than you will cycling.

efficiency has a different meaning in running that it does in cycling. The second thing is that one could go longer (and expend more energy) cycling than running. End goal is energy expenditure, and cycling would go further in that department.

The other thing i would suggest is to incorporate some weight lifting. Not to get big, but to increase muscle mass, which requires higher amounts of energy to maintain than a corresponding mass of fat.

[velofinds]

Just go for long rides before eating breakfast. Only drink water. Skip the post ride carb gulps. Eat your regular diet. Do not increase consumption. 15 Kg can be lost in 2-3 months of diligent effort but it won't be easy.

This is good practical advice and pretty much all you need. Don't overthink this stuff- in doing so, you overcomplicate something that isn't all that difficult to figure out (now sticking to- that's a different matter).

[2metalhips]

Look at what you are eating. A plant based diet will help you lose weight and be much better for your overall health in the long run.

[SoCalSteve]

You have to burn fat to lose it. Constantly filling your glycogen stores will raise insulin levels and store MORE fat and actually work against you


Just go for long rides before eating breakfast. Only drink water. Skip the post ride carb gulps. Eat your regular diet. Do not increase consumption. 15 Kg can be lost in 2-3 months of diligent effort but it won't be easy.

GL

How long a ride are you talking about without eating? I’d be so afraid of bonking doing this. Seriously afraid. Have you ever bonked? It’s not fun. At all.

Anything more than 2 hours without replenishing your stores is a recipe for bonking.

Not sure this is such great advice. Again, if you’ve ever bonked, you will never ever want to do this again. Ever.

[Louis]

The second thing is that one could go longer (and expend more energy) cycling than running. End goal is energy expenditure, and cycling would go further in that department.

Perhaps, but if you have a limited amount of time then going with the greater calories / minute activity may allow you to burn more calories.

[happycampyer]

If you get a power meter, it might be worth have a metabolic test done on a bike to see how much fat you burn at different wattages. Going by heart rate can be tricky, because of cardiac drift (for example, if you do a 20 minute interval at 200 watts, your heart rate will be higher at the end of the interval, even though your output is the same).

Even so, as others have said, you wouldn't want to train endlessly at the wattage that burns the highest percentage of fat. Aside from going out of your mind from monotony, you need to train in different zones to get proper adaptations in fitness. But it is good to know that at, say, x watts you burn the highest percentage of calories from fat so that you can structure some workouts around that wattage. Bear in mind that you will need to retest periodically, since those numbers change as your fitness improves.

As mentioned, some weight training is a good idea, both to help offset the potential loss of muscle mass as you lose weight and to burn more calories at rest (and not to mention other benefits like bone density, looking good in a bathing suit, etc.).

On the intake side, be mindful of what you are eating. Just because you have burned enough calories on a ride to be able to eat two croissants and drink a milkshake doesn't mean that you should. At a minimum, cut out all processed sugar/foods. I've lost a decent amount of weight (10 - 11lbs/4.5 - 5kg) over the last month by following a pseudo-paleo diet. The next 10 pounds are going to be much harder to lose.

[dustyrider]

I prefer to burn fat by not gaining it. I know you're looking for something you can monitor via cycling, but I just feel like burning fat is the wrong way to think about exercise. Exercise should bring you enjoyment, gains in performance, and increased health benefits first and foremost.

If I stop consuming beer/alcohol, I can keep 10 pounds off without changing anything else about my diet or exercise. If I limit my food intake, I can keep 10 pounds off without my performance suffering. When I do both at the same time, I feel good enough to keep another 5 pounds off because it becomes easier to be so much more active. I like to think about my diet as a way to improve my recovery; it makes it easier to stay on track because I'm making choices for the moment rather than the next bike ride/run. In the long run, the sooner I can run/ride the happier I'll be.

Sorry to derail the thread. There's some good knowledge up in here! :cool:

[11.4]

Doing a long fasting ride isn't a good way to go about this. The clinical evidence is that you can lose weight from it, but you lose a significant part of it from muscle mass. It also depletes mineral deposition in the bones and leads to degradation of tendons, which leaves you in worse shape than you are with some extra weight on you. A good example of this is some training that Sky did about three years ago early season, thinking that fasting rides would overall be beneficial. However, they led to abnormal cortisol levels, tendon weakness (which led to all kinds of muscle and joint issues that directly affected performance) and reduced muscle mass.

There still seems to be a search here for an optimal training band for weight loss. If you want weight loss, maximize your caloric burn and minimize your caloric consumption. If you want cycling fitness or overall fitness or health, temper both those by being smart. Limit your caloric burn to workouts which don't have a detrimental effect on you, and improve your calories consumed by eating wisely -- avoiding the easy components such as processed carbohydrates, sugars, and so on.

Perhaps the missing issue here is how the body regulates. We understand better now how complicated a feedback system is at work. It's not only insulin, but also cortisol, it's about intestinal biome metabolism, and a variety of other systems that all interrelate and act to confound your best efforts to lose weight. In the end there's no simple answer. One can't even exercise hard enough to take off the pounds from what one eats. It ultimately comes down to consuming less -- that's the only consistently demonstrated solution that your body doesn't try to work around, and even then, after taking weight off, your body will self-regulate to a new higher level of efficiency to maintain weight at a lower body weight. It's not an easy answer or a pretty picture, but it's basically the only answer in town.

[weisan]

11.4 pal, thank you.

[happycampyer]

<snip>

There still seems to be a search here for an optimal training band for weight loss. If you want weight loss, maximize your caloric burn and minimize your caloric consumption. If you want cycling fitness or overall fitness or health, temper both those by being smart. Limit your caloric burn to workouts which don't have a detrimental effect on you, and improve your calories consumed by eating wisely -- avoiding the easy components such as processed carbohydrates, sugars, and so on.
I would just note that this can be--and shouldn't be--over-done, which I'm pretty sure you would agree with. If on a rest day one burns, say, 2,000 calories, and on the next day one goes for a long ride and burns 5,000 calories that day, one can't just take in 1,000 calories a day for both days and expect to lose weight, or at least not fat weight. The intake should be at a deficit, but not such a deficit that it causes the body's metabolism to slow down.

To the OP, if you're looking to lose 15kg, you probably need to do more than cycling. Try to avoid being sedentary. Walk or ride a beater bike for short trips if you can. Park at the far end of a parking lot instead of searching for the closest space. Take stairs. What you do off the bike is as important as what you on it.

[ripvanrando]

How long a ride are you talking about without eating? I’d be so afraid of bonking doing this. Seriously afraid. Have you ever bonked? It’s not fun. At all.

Anything more than 2 hours without replenishing your stores is a recipe for bonking.

Not sure this is such great advice. Again, if you’ve ever bonked, you will never ever want to do this again. Ever.

2 hours? I suppose it depends upon the effort but OP wants to lose weight and most rides are not at or near threshold. I guess what is a long ride.

447 Km is about as far as I have ridden without food but 3-4 hours with two bottles of water would be more typical for me.

The key point of the base period in the old days at least was to develop the aerobic capacity and ability to burn fat. Stuffing one's face with sugary drinks releases insulin inhibiting the release of free fatty acids. Obviously blood glucose levels and stored glycogen are critical during a race. However, my point remains. To lose fat you have to burn it one way or another and avoiding the roller coaster of insulin spikes helps in that regard, especially during rides when the key objective is weight loss. YMMV

Edit: my original post indicated to eat a normal diet.....I'm not advocating fasting.....glycogen stores and liver should sufficient stores to fuel 2 hour rides when much of the energy is fat oxidation. 14 hours of riding a week is a lot. Eating a normal diet and not increasing food intake.....weight should melt off

[velofinds]

I understood exactly what ripvanrando was saying. I don't think any reasonable person would interpret that to mean riding to the point of bonking. The description fits a classic medium-to-low intensity ride.

The length of the ride and what one considers a "long" ride to be will obviously vary from person to person, but one would have to gradually build up one's ability to ride in a fasted state as opposed to attempting a 2-3 hour ride right away, which would only end up being a miserable experience.

[echappist]

I would just note that this can be--and shouldn't be--over-done, which I'm pretty sure you would agree with. If on a rest day one burns, say, 2,000 calories, and on the next day one goes for a long ride and burns 5,000 calories that day, one can't just take in 1,000 calories a day for both days and expect to lose weight, or at least not fat weight. The intake should be at a deficit, but not such a deficit that it causes the body's metabolism to slow down.

To the OP, if you're looking to lose 15kg, you probably need to do more than cycling. Try to avoid being sedentary. Walk or ride a beater bike for short trips if you can. Park at the far end of a parking lot instead of searching for the closest space. Take stairs. What you do off the bike is as important as what you on it.

yes to both points made.

I was told that at my weight (70kg), one should average about 500-700 kcal deficit per day. My rest metabolic need was probably 2400 kcal/day.

I've also not done any fasting rides for more than 90-105 minutes. Sooner or later, I need to begin fueling again

[ripvanrando]

The best advice I read somewhere was along the lines, "You can't out ride a bad diet" and exercising during a true fast is a bad dietary idea. Using last night's dinner to fuel a morning ride? I wasn't advocating training while fasting.

An important consideration is how much time one can devote to riding. If someone does not have a lot of time and say can only ride 3 days per week, those rides should be pretty hard whereas if someone has the time to ride many hours per day, these rides would naturally be lower paced (zone 2 or maybe some in zone 3). I do like the TSB lines in performance management chart in TP as a way to keep it honest.

Someone mentioned cortisol. As we get older, hormonal recovery is not as easy irrespective of diet or at least for me. Joe Friel recommends 9 day training weeks for some older riders so that they can get the essential intensity rides in.

33 pounds that the OP has to go is a lot to lose. The irony is that is my exact amount to racing weight that I have to lose. Maybe a little side bet on who get there first. I'm just not motivated to stop stuffing my face.

[benb]

Yah if you're time limited at all on how much cardio/riding you're doing ignore all this stuff and just go out and ride as hard as you can. You'll burn more calories and probably more total fat calories as well.

As others have said, that fat burning zone is just based on "percentage of calories burned from fat". It is not showing you what is the zone that actually burns the most calories from fat.

e.x.:

Fat burning you might be riding 14mph or something and you'll come up with a calories/hour of 400 or something. And say that's the "zone" and you burn 50% from fat, so 200 calories of fat and 200 of glycogen/whatever.

If you burn 1000 calories per hour riding at 20mph you supposedly only burn 35% of your calories from fat. That's 350 calories/hr of fat.

Most people who are time limited are not riding at 20mph average pace, that's just an example to show how flawed the whole thing is.

This whole thing is one of the reasons so many people in the gym can't figure out why they never lose weight when they go to the gym 3-5X a week and use the cardio machines at low intensity for 20-30 minutes each time.

If you're ripvanrando and you ride 15k miles per year or something you can't ride high intensity that much so maybe some of this stuff starts to matter but for the rest of us just ride for speed/power/endurance whatever the training plan is and the weight will come off if you ride enough and don't over eat.

I know for me there is a point somewhere between 7-10 hours per week where the weight is just going to start to come off no matter what. I don't have the capacity for endless hours some people do but that is still enough time riding that I can't ride that much at high intensity but the average intensity is still enough I lose weight fairly quickly and then have to work to maintain it.

[echappist]

Yah if you're time limited at all on how much cardio/riding you're doing ignore all this stuff and just go out and ride as hard as you can. You'll burn more calories and probably more total fat calories as well.


only caveat here is that it leads to over-reaching, if not over-training

when my hours got reduced over the years, i begin to do more and more high-intensity (threshold level or above) on a weekly basis. When i started, i didn't dare do more than 2 sessions/week; last year, it got to 4 or even 5/week. Being able to do high intensity takes a few years (or perhaps months, if one's lucky) to get there, and it's not recommended that one dives into the deep end immediately

also, this is the other reason why cycling is better than running for losing weight: you can't go that long (or hard) as a runner when you are 15kg over weight due to the physical impact. It's pretty much a non-issue for cycling.

[hobbanero]

Echappist's data really tells the story here. For a long time we were told that Zones 1 and 2 are where you ride to burn fat. In those zones, you are burning primarily fat (rather than glycogen) as fuel, but you are not burning as many calories per hour. Since even at VO2 efforts you are still primarily aerobic, you are always burning fat. And you have to factor in the caloric requirements for recovery.

Below is a screenshot from a metabolic test I did a while ago on an ergo with a gas exchange mask to measure fuel usage.
http://i65.tinypic.com/5lxo5j.jpg

This shows that you still burn plenty of fat at tempo (I think 320 was my LT at the time), but the ideal pace for fat burning is zone 1/2. As a reference, at the time my threshold HR was 170bpm, and 120-140bpm was Z2.

But, interestingly, I always lose the last couple of winter kilos after I transition from Z2 work to VO2 intervals. Even though my training load (measured by TSS) probably goes down a bit, the high intensity work seems to burn off more fat. Why? Recovery needs? I don't know for sure...but it happens every season.

So you can go harder and still burn lots of fat. You have to keep in mind your available training and recovery time, of course. Going hard all the time obviously leads to problems.

[54ny77]

To burn fat fast, you need at least a 5.7 liter Hemi V8.

http://static.neatorama.com/images/2006-06/hemi-powered-grill.jpg

[echappist]

But, interestingly, I always lose the last couple of winter kilos after I transition from Z2 work to VO2 intervals. Even though my training load (measured by TSS) probably goes down a bit, the high intensity work seems to burn off more fat. Why? Recovery needs? I don't know for sure...but it happens every season.

So you can go harder and still burn lots of fat. You have to keep in mind your available training and recovery time, of course. Going hard all the time obviously leads to problems.

same here; high intensity stuff and training races actually make me leaner, despite the reduced energy output during the week

perhaps all that after-burning hypothesis is valid after all
To burn fat fast, you need at least a 5.7 liter Hemi V8.

http://static.neatorama.com/images/2006-06/hemi-powered-grill.jpg

ain't no replacement for displacement