Does fasted cardio burn more fat
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sflano1783
Posts: 117 Member
Hi does fasted cardio eg walking for 45 minutes burn more fat??
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sflano1783 wrote: »Hi does fasted cardio eg walking for 45 minutes burn more fat??
Not really. Big deals have been made in diet literature about small differences in fat burning processes that may exist at the very outer margins of what matters for weight loss, if they exist at all.
If you eat 2,000 calories and do 400 cals worth of cardio, you are going to have a net of 1600 cals for the day, no matter when you eat the food and do the exercise. If it's 1595 or 1605, it isn't going to affect your weight loss in any material way.
I prefer to do cardio fasted but I don't think it's giving me any extra weight loss.11 -
I think one has to be careful doing any kind of exercise while being in a 'fasting state' if the fasting lasts over 24 hours. In that state you might lose more weight but the body might start burning muscle tissue. Though a low intensity training probably won't hurt you. I never noticed any difference in weight loss during a longer fasting whether I did some walking or just sat on my *kitten* all day. If what you mean is exercise during IF a shorter fasting IMHO the more you train the more fat you will burn obviously within one's limit, but you can go for it. Walking is great for fat loss though I personally prefer a higher intensity training, each to their own.1
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No.
Loss of bodyfat is due to a calorie defcit over time and not what fuel ratio you burn during short periods of exercise.
At lower exercise intensities you burn a higher PROPORTION of fat to carbs but you are also burning less calories and quite possibly less AMOUNT of fat compared to higher intensities that burns more calories.
If someone manipulates their exercise intensity to burn more carbs or fat that is negated when they next eat with more carbs or fat from your food either being stored or used.
Fasting for short periods does not deplete your onboard carbs stores enough to significantly influence the ratio of fat to carbs burned during exercise. e.g. you might have 2000 cals worth of glycogen stored and fasting overnight you are burning very, very little of that as you are running almost entirely on fat.
Yay - sleep yourself thin!
When I was hooked up to a gas analyser in a sports science lab it wasn't until my pulse hit 130bpm (rough equivalent to cycling at 16mph) that carbs overtook fat as the predominant fuel being used.11 -
Your body is a dual fuel system using carbs and fat. Carbs provide the quick burn fat the slow burn. Your body is constantly using a combination of the two.
Your body, fully fueled has around 1500 calories available.
You can absorb approx 250 cals per hour
This means that if you only burn carbs you will run out of energy after around 5 hours walking. But your body doesn’t only burn carbs and the idea of fasted training is to change the ratio slightly and thereby push that 5 hours out further or be able to go harder. Even a small change for an endurance athletes can mean the difference between first and second place.
For basic weight loss though, unfortunately completely irrelevant.... sorry6 -
Nope. I've trained fasted for 10 years(no breakfast and don't eat till after 11am-12pm each day) and when I was heavier, had NO EFFECT because I was still eating close to maintenance at that time.
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6 -
Another "no" here. Please read the human studies.
That said, if you personally like to train fasted then go for it! 🙌🏿1 -
My records are pretty meticulous (and may not be true for others) but I noticed no difference in rate when I did cardio fasted or not. Mind you my cardio is mostly steady state, perhaps results are different at higher intensity levels?
Personally, I just don't enjoy working out fasted, so whatever benefits might exist, would be outweighed by my lack of effort.2 -
Maby yous ate carbs on your last meal from the day before cause when there's no carbs in system you start burning up fat in a fasted state2
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I walk every morning early before breakfast...fasted. I put on 20 Lbs over the course of 2020. It's irrelevant for weight loss. You need to understand that your body is constantly cycling through different fuel sources, and yes, you use more fat for fuel with both low intensity exercise and fasted...but it's only for that particular moment and it isn't net fat loss...you are constantly burning and storing fat during a given day. Your overall calories will determine net fat loss or gain or homeostasis.
You burn more fat sleeping than anything else you do in a given day...but I wouldn't recommend sleeping all day as a weight loss solution.6 -
I have trained fasted every morning ever since I figured out that breakfast is not the holy grail of meals for me. It doesn't seem to have made a blind bit of difference as far as losing weight is concerned, except when combined with a calorie deficit. And I credit my resistance training for keeping my muscle levels and dropping fat, not the fasted state training.4
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sflano1783 wrote: »Maby yous ate carbs on your last meal from the day before cause when there's no carbs in system you start burning up fat in a fasted state
No that's not how bodies work - you are burning fat 24 x 7 and completely using up of your glycogen is called hitting the wall (running, triathlon) or bonking (cycling). If you do manage that after hours of hard exercise you basically lose the ability to exercise or even think straight.
Heard of the Brownlee brothers? This video is what using all your carbs up actually does to you.....
https://www.youtube.com/watch?v=liCRrheKIOI
Read through the responses again, it's not carbs first and then fat second. It's both fuels all of the time in varying ratios. Even people like me with high carb diets are burning fat 24 x 7.
I don't know where you have got your ideas from but I'd suggest changing your sources of information - that this thread is remarkably consistent in the advice from many different people should tell you something.9 -
I always look to peer reviewed journals for these questions - because anecdotes are usually all over the place and unreliable. This meta analysis does seem to suggest that fasted cardio does increase fat oxidation - but for the average person I'm not sure how much of an impact it would make.
"Conclusion
This systematic review with meta-analysis suggests that aerobic exercise at low-to-moderate intensity, performed in the fasted state, induces an increase in fat oxidation, when compared with exercise performed following consumption of a carbohydrate-containing meal. Despite high heterogeneity of the data, no difference appears to exist between exercising in the fasted or fed states in relation to variations in NEFA concentrations before and after exercise. In contrast, variation in relation to glucose and insulin concentrations appears to be higher in the fed states. Future meta-analyses and randomised clinical trials, inclusive of an evaluation of the long-term effects of aerobic exercise on fat and carbohydrate metabolism in the fasted and fed states, will be necessary to confirm the findings of the present review, as well as to identify their real benefits or consequences for long-term health."
https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effects-of-aerobic-exercise-performed-in-fasted-v-fed-state-on-fat-and-carbohydrate-metabolism-in-adults-a-systematic-review-and-metaanalysis/0EA2328A0FF91703C95FD39A387168114 -
sflano1783 wrote: »Maby yous ate carbs on your last meal from the day before cause when there's no carbs in system you start burning up fat in a fasted state
No that's not how bodies work - you are burning fat 24 x 7 and completely using up of your glycogen is called hitting the wall (running, triathlon) or bonking (cycling). If you do manage that after hours of hard exercise you basically lose the ability to exercise or even think straight.
Heard of the Brownlee brothers? This video is what using all your carbs up actually does to you.....https://www.youtube.com/watch?v=liCRrheKIOI
Read through the responses again, it's not carbs first and then fat second. It's both fuels all of the time in varying ratios. Even people like me with high carb diets are burning fat 24 x 7.
I don't know where you have got your ideas from but I'd suggest changing your sources of information - that this thread is remarkably consistent in the advice from many different people should tell you something.
The video is so beautiful! I'm literally crying 😭
And also bonking sucks! 😭3 -
In addition to all of the other data provided here I can provide some empirical evidence that it doesn't matter in the end. I used to run Marathons and during training ran 40 - 50 miles per week. At that stage I was tracking my food intake and weight religiously. For a couple of years I ran all but my once per week long run in a morning fasted state. I then changed my routine to eat breakfast first and followed that routine for roughly 1 year. My weight and calorie intake was consistent -- bottom line your body sometimes uses fat, sometimes uses glycogen, sometimes uses muscle etc.. for fuel and at the end of the data it all works out to calories in vs calories out.4
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sflano1783 wrote: »Hi does fasted cardio eg walking for 45 minutes burn more fat??
Unless you are very unfit aerobically, and gasping for breath during that walk - your main source of fuel is probably going to be 80-85% fat anyway.
Unless you literally just ate and insulin is still elevated in which case you burn whatever you ate for fats and carbs until insulin drops then back to normal fat burn.
But your overall day for fuel source amounts didn't change.
If you were doing some cardio pretty intense, the fasted state could actually have you doing it less intense compared to fed at some point before the workout - and less intense means less calorie burn overall, so less fat and carbs burned overall. Even though the ratio of fat to carbs might be a few % higher burning less calories.
If you are that marathon trainee with hours of running you may initially benefit training the body to use better ratio of fat to carbs right from the start, so as to preserve those limited carbs, but it'll eventually learn that anyway.
For your walk though - no.3 -
I'll throw out a semi-interesting data point here just for the hell of it. I monitor my HR every day for my 75 minute cardio workout. Normally, this is an 85-100 watt workout on an exercise bike. My HR if in a fasted state is usually 101-103. However, if I eat lunch first, it can range from 106 - 112, normally around 109. I have often wondered what the significance is, if any, or what it says about weight loss, exercise, and meal timing. My uninformed hypothesis is that it takes a bit of extra effort on top of the cardio to digest the food, hence the bump up in HR. Not sure what that means for the overall net caloric day, though - probably nothing.1
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Maybe I burned 200 Cal of fat, or maybe I burned 160 Cal of fat and 40 Cal of carbs, or maybe I burned 200 Cal of fat during my walk today.
What difference will it make as to whether I will lose or gain STORED energy reserves in the form of fat at the end of the week?
The amount of energy reserve change my body will undertake is going to be solely determined by whether and how much my *absorbed* calories exceeded or came short of the total calories of energy expenditure I *actually* put out during the week. Not by whether I expended fat or carbohydrates or even protein, but by the mixed total balance overtime
Regardless of the source of the calories and their timing.
Sure. By effing around I might get an extra 5% benefit. Maybe eat at totally different times than I feel like and only food that I cook while wearing a pink polka dot apron and rubbing my head clockwise.
But I would rather worry more about getting the caloric balance right (not too high but also not too low and creating an excessive deficit) and going home with the 95% benefit that will result in reasonably slow and consistent progress.
Because, you know, two extra Pepperidge farm cookies sitting in my cupboard and consumable in 2 seconds if dunked in hot (coffee) or cold (milk) liquid.... have 240 Cal.... so there's that! 😘5 -
I'll throw out a semi-interesting data point here just for the hell of it. I monitor my HR every day for my 75 minute cardio workout. Normally, this is an 85-100 watt workout on an exercise bike. My HR if in a fasted state is usually 101-103. However, if I eat lunch first, it can range from 106 - 112, normally around 109. I have often wondered what the significance is, if any, or what it says about weight loss, exercise, and meal timing. My uninformed hypothesis is that it takes a bit of extra effort on top of the cardio to digest the food, hence the bump up in HR. Not sure what that means for the overall net caloric day, though - probably nothing.
@lgfrie
When you eat your stomach needs more bloodflow for digestion.
Your pulse goes up fed v. fasted as you have the same exercise demand plus the demand for digestion - you need to pump more blood. Yes you are on exactly the right track with "a bit of extra effort on top of the cardio to digest the food".
However, (for weightloss / daily energy balance) that increased demand from feeding has just moved from one part of the day to another so it's a wash assuming overall food intake is the same.
It's something that endurance athletes that need to eat during prolonged exercise have to struggle with, your digestion is compromised due to the prolonged muscular demand for blood. You will see endurance athletes eating little and often to match intake to what their stomach will tolerate and going for quick and easy to digest foods (esp. simple sugars).5 -
I would encourage you to do your own research on this. Many to most people will share their experiences and that's great! But it's just that...a nonmedical opinion. Research has suggested that there may be as much as a 6% increase in fat burning due to fasted cardio. Again, it's research in medical journals that could best answer your question.
Inevitably it is eating at a deficit over time that will create weight loss. With that being said, I like fasted cardio. I will usually prefer a fasted run to any other one. Big fat however, if I were to run fasted and come home and overeat then no matter how great the run was the fasted cardio wouldn't have made a difference and would have been done in vain.
Also and most importantly if you enjoy doing cardio fasted as opposed to not doing cardio in a fasted state, then ultimately, that is what matters most!1 -
sflano1783 wrote: »Hi does fasted cardio eg walking for 45 minutes burn more fat??
Not really. Big deals have been made in diet literature about small differences in fat burning processes that may exist at the very outer margins of what matters for weight loss, if they exist at all.
If you eat 2,000 calories and do 400 cals worth of cardio, you are going to have a net of 1600 cals for the day, no matter when you eat the food and do the exercise. If it's 1595 or 1605, it isn't going to affect your weight loss in any material way.
I prefer to do cardio fasted but I don't think it's giving me any extra weight loss.
This. I prefer to run fasted, so do, but I walk at any time of the day and there's no reason to think walking after eating is somehow sub par.1
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