This isn’t even super relevant to my training currently, it’s just something I’ve always been confused about. I often read about zone 2 being “better for losing weight” because almost definitionally you are disproportionately burning fat as opposed to carbs. Why would burning carbs vs fat matter at all ultimately? A calorie is a calorie no? Every calorie you burn in the form of a carbohydrate would have been eventually converted to fat if it was an excess calorie.
Does the answer have something to do with the relative energy efficiency of fat vs carbs? Does 1 hour in zone 2 burning mostly fat burn more calories than 1 hour in zone 3 or 4 burning more sugar? That doesn’t seem right. Maybe people are talking about it being “better for losing weight” holding perceived effort constant instead of time?
From a weight loss perspective, why does it matter at all if your body is using fats or sugars?
For a one hour workout, you might get away with that. If you go longer then 2 hours, at higher intensity without fueling, all carbs and glycogen will be exhausted. Because the intensity is too high, you can’t rely on fat and your body starts to burn more protein. To the point that you will cannibalise your body and eat up lean mass.
After that workout, you will be craving carbs, eating carbs, and 1.5-2 hours after eating those carbs, they will have converted to fat. Result = more fat, less lean body. That’s also weight loss, but not the kind you’re after…
Calorie counting works for sure, but not for endurance athletes. And it is way more frustrating then teaching your body too work relatively hard while burning predominantly fats. The more your body learns to use fat as fuel, the more it will use fats through out the day. If you keep putting in carbs, all activity, even the lightest work will be fueled by carbs. Simply because the carbs are always at hand…
Intensity drives the demand for fuel. If you have a poor base fitness (aerobic), the crossover point where you burn more carbs than fat will be lower than when you are better trained, i.e. more efficient. Zone 2 helps build your aerobic fitness, if done correctly, together with eating well.
You can’t “teach your body” to burn more fat, by limiting the carb intake. You’re setting yourself up to fail if you go down that path. Ride or run more, at an easier intensity than most people think you need to, and you will build the base.
Thanks, good read!
One point that was not enough hammered on in my opinion is that lower intensity exercise is easier to recover from. That on its own will make it easier for the subject to do more (as in multiple times a week) and longer (not necessarily per session but on a longer timeframe like months/years).
Someone coming of the couch with the intent of starting to move to loose some weight, going too hard immediately, will be back on the couch within days/weeks, completely exhausted and disappointed for another failure. And it’s not his fault, he just wasn’t informed correctly. The advice should be to start with a daily walk/ride at a pace they can easily handle. Take it from there and learn to enjoy.
As far as I understand, in the majority of subjects kJ expended through exercise is not the main factor in estimating energy balance (unless you are a pro, incinerating +3.000 kJ avg per day, every day… so you are not in the majority of cases). And as far as I understand, volume is king, i.e. at the end of the day you have to count kJ, and at what intensity is neglectable. But the MAIN factor to consider is kJ intake.
What the vet would tell you to do if your dog was overweight? “Feed it less, and go for more walks.”
Anything more complicated is either to aid adherence (which is by far the hardest part of it), or to probably try and sell you something you don’t need.
Exactly. The truth is that Zone 2 means you’re probably converting fat when creating ATP for your muscles. Just because fat molecules are the inefficient-but-easy ATP fuel source in Zone 2, especially at the beginning of a fitness journey, does not mean that your visceral belly fat (what my fiancee’s aunt calls her “cheese wheel” lol) will shrink.
What your body first turns to for fuel at a given intensity is a completely different conversation than how your body turns excess carbs and protein into fat. And that conversion to fat in turn is also different from where your body stores that fat, which I believe is largely based on genetics – so the only way to lose fat in any particular location (e.g., you want six-pack abs or a smaller bum) is to lower your entire % bodyfat.
Nice, I think I had already seen it, but I think it focuses a lot on the duration in time of the training. I guess you wouldn’t need the same amount of carbs in a 1 hour sweet spot workout as you would in a 1 hour over unders/VO2max workout.
Perhaps it would be easier to ask if low intensity workouts that exceed 45-60 minutes and do not exceed 120 minutes need that load of carbs that, for example, the graph in the link above indicates, or would it be more beneficial to do them without introducing anything. I mean tempo workouts, even endurance…
Hello,
I recently looked up a lot about this topic because i to want to lose weight but also build up a good basis endurance and slow twitch muscles (that help with efficient fat burn). So here are my finding but any confirmation is welcome:
No intensity is purely burning one fuel group, you always mix these groups up. Incyd uses this infor-mation en there data to determen something that calls you’re FatMax. The point where you burns the most amount of fat and also gives you the number of Carbs you burn while doing this. I (and many others) are not as fortuned to have access to Incyd data but you’re upper zone 2 is the next best thing to compare it with (or in breathing terms: a workout where you can still talk but in hesitations). When you do long trainings of these you get the most benefit four your weight loss but have to keep in mind to fuel some carbs so you can keep going. It’s good to incorporate some harder training also in here. I would say 80% base 20% hard.
A good tool for this is the EatMyRide app. Here you can plan your ride and the app tells you how many carbs you are going to burn and even gives you a fueling plan, or you can decide with the information from the graph of your carb-reserves to not fuel extra. After your workout it gives you a percentage of cerbs vs fat you burn. Very interesting!
Now my question for the experts if i may : I’m I on the right pad if when I do a zone 2 training like this. Afterwards I look at my burned calories and only refuel my burned Carb calories? This on top of reduc-ing calorie intake for weight loss. For example with the pictures above: my daily calorie intake is 2600. I burn 827cal of witch 27% carbs equals 223cal. So my new intake for the day is 2823. This was my conclusion because in that manner I get enough fuel when I do hard training day’s with more carb burn and have an extra fat burn kick in base training. Any thoughts, additions or tips? Many thanks!
That’s around AeT, aerobic threshold, FatMax is a bit lower. Be careful in interpreting this. It’s more like talking full sentences without problem, every now and then the need for a deeper breath.
Longer trainings at Fatmax should never need any fuelling, at least not if longer means 4 -5 hours.
If that is based on time, it is way too much intensity. The 80/20 rule was made for sessions. 4 easy, 1 hard(er).
If you train, or probably better in this case , move, for weight loss, longevity, health, there is NEVER a need to go hard. Just make sure that you move enough at low intensity. And that low intensity has no need for supplemental fuelling.
Cut down the calories, especially carbs, and move a lot more at low intensity. That will always work if you’re honest with yourself. Avoid higher intensities, because you will crave carbs. Don’t rush, let it happen. You didn’t put on the weight in 3 months, so you can’t expect it to vanish in 3 months.
Avoid planning distances, work with duration. As you get fitter and more lean, your pace will go up quite fast. So don’t go with a target that is fixed in distance. Set a duration and slowly increase it, week by week by 5-10%.
If you start to enjoy that ‘movement’ and are tempted to do something more challenging, that’s when you can safely introduce some more intensity to increase performance.
But if you feel like going harder now, don’t hesitate to do it every once in a while. If that motivates you, if you feel good about it, please do. But don’t fall in the trap thinking that you need to go hard all the time because that will wear you out.
Some good indications that you’re doing all right:
Just breaking a minimal little sweat
Never out of breath or exhausted
A ‘comfortable’ tiredness after your workout session that makes you feel relaxed. A sense of feeling good, proud of what you just did.
No desire of immediately starting with binge eating. Just enjoying some fruit or nuts while relaxing and recharging for your next outdoor adventure
Thank you for the feedback. I was under the impression that “zone 2” training was best for slow twitch muscle training and the ability to burn fat at a higher power rate but also for fat burning training In general. Thanks for clearing that up.
As for the 80% 20% this is indeed separate trainings, like for a week plan were you can fit in one ses-sion with intervals to train you’re VO2max and make the lactate that your slow twitch muscles can learn to discard. It’s for me personally because I found oud that my basics goes well but I almost instantly burn up when I go above that.
AeT and FatMax are close. The important thing to remember is that being a bit lower has almost no negative influence while being a bit to high has significant impact.
The problem with this starts in the first paragraph with the proposition that glucose only yields 2 molecules of ATP. Fat 18. That’s entirely untrue. Glycolysis of glucose to pyruvate/lactate indeed only produces 2 ATP. However the pyruvate then enters the Crebb’s cycle and eventually oxidative phosphorylation. Here another 30 molecules of ATP are generated. So glucose actually produces 32 molecules of ATP. But then there is the argument that “Ah but glycolysis is anaerobic and oxidative phosphorylation is aerobic so with exercise you never get those extra 30”. That is also nonsense. A skeletal muscle is never anaerobic enough to prevent oxidative phosphorylation except perhaps under extreme explosive exercise to failure conditions. Oxidative phosphorylation continues despite incredibly low oxygen tension within exercising muscle (0.4kPa vs 21kPa in the air we breathe). So a calorie is a calorie. Burn more than you eat and you will lose weight. Eat more than you burn and you will gain weight. Whether the weight you gain is fat or muscle depends on your exercise though. The main problem is most people don’t realise how little you have to eat to offset exercise or conversely how much exercise you have to do to get rid of that jelly donut (about 3km running).
: I’m I on the right pad if when I do a zone 2 training like this. Afterwards I look at my burned calories and only refuel my burned Carb calories? This on top of reduc-ing calorie intake for weight loss. For example with the pictures above: my daily calorie intake is 2600. I burn 827cal of witch 27% carbs equals 223cal. So my new intake for the day is 2823. This was my conclusion because in that manner I get enough fuel when I do hard training day’s with more carb burn and have an extra fat burn kick in base training. Any thoughts, additions or tips? Many thanks!