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Comment by SoftTalker | Hacker News Reader

The "treat yourself to a donut" suggestion got me. Sure, eat a donut, completely negating the caloric burn of the 30 minutes of aerobics you're motivating/rewarding yourself for.

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For plenty of already-in-shape people, the calories expended during the exercise are largely incidental, with the goal of exercise being to enhance or maintain some other property of their physical capacity.

You'll still have improved cardiovascular fitness even if you aren't losing weight.

Any ways, a lot of studies have shown your body has a variety of methods that attempt to counteract excess calories burned, like reduction in non-exercise activity thermogenesis.

I'll disagree slightly, though clearly you are correct that if your goal is to offset calories, then eating a donut negates the benefits of the exercise activity.

My disagreement is that I think exercise should not primarily be about calories - it should be about fitness. And almost all of the fitness gains from exercise persist even if you replace the calories with a donut.

Exercising for 30min and then relacing those spent calories with donuts is FAR better than not exercising and forgoing those extra calories.

Exactly - and on top of that being super extra lean (for vanity purposes) is often actually detrimental to real world performance anyways. There's a balance to everything.

Of course this assumes that in addition to the single donut the rest of your diet is decent - if you're eating shit all day then you are asking for an injury

that not how it works. that's not how any of this works.

the aerobics build up muscle that will always be burning calories by merely existing. a donut here and there won't make a negligible difference, as long as the weekly aerobic activity level is maintained.

Eeeh. Exercise doesn't spend enough energy for high calories foods to be worth it. If you want to lose weight that is. A donut is a lot of exercise and muscle building leads to a small but not sufficient calorie spend. The majority of calorie spend still comes from the organs and general body maintenance

> Exercise doesn't spend enough energy for high calories foods to be worth it. If you want to lose weight that is.

Tell that to all the lean 150 pound / 68kg runners stuffing their faces with high calorie foods all the time.

_Athletes_ are completely different from the normal people looking to exercise. Can you spend 4 hours of your day exercising?

If you are single and short commute, it is doable. People spend hours watching TV, looking at phone.

I don't think it's reasonable. That becomes basically the only thing to do outside of work. Highly unlikely at the very least.

If most people really wanted to I think they could. Split it into multiple blocks

Even most professional endurance athletes rarely hit 28 hours per week of actual training time. That would be like a peak week in a training plan before tapering leading up to a race.

Even more contrary to GP's claim, the top American marathoners are only doing ~13 hour weeks of running before their races. It's public data on Strava.

Try only 4 hours a week of exercise. Most lean runners are only getting that amount of time running in and still eating high calories, because 4 hours of running is ~2,500 extra calories burned every single week.

You're replying to a person saying "exercise doesn't spend enough energy [...] if you want to lose weight" by referencing "lean 68kg runners".

Do you think they want to lose weight?

I wanted to lose weight. I ran a lot (only 5 hours out of the week), ate the same high caloric foods, and lost a lot of weight. Clearly GP's assertion isn't correct, because enough exercise does lose weight.

endurance athletes are laughing

plenty of endurance athletes are pudgy, not lean at all . Usain Bolt is leaner than many endurance athletes. Training for endurance and being lean are different. Some runners get a nice toned body, but this far from the norm.

Athletes are not the same as normal people, who have 1h or so a day to exercise.

You can't outrun a bad diet is a common saying around my parts.

Yes, the literature on this bad. It's even worse than that. Metabolic adaptation means you may think you burned 400 kcal with a long run according to the tracking app, but maybe your body, on net, only burns 100-200 kcal, so this throws off the math.

Now you're just making things up. On any training plan, a long run would be a minimum of 6 mi / 10 km. No adult is going burn less than 400 kcal over that distance, it isn't physiologically possible. And any metabolic adaptation will only be a few percent at most: running economy only improves slightly with training.

Meh..not as much as you hope or expect. There is a popular channel on youtube @ErikTheElectric who does these huge food challenges, but also tons of cardio like marathons and 100-mile bike rides, to try to offset it. He weighs 170. At his height I weigh 15 lbs less, simply from eating less despite doing much less cardio than him. The body is very good at increasing its efficiency in response to exercise. You will be working your ass off doing cardio, but the weight just not budging much beyond water fluctuations. Many people report this. They will do 20-thousand steps and stop losing weight after a few days.

As for muscle, a pound only burns 11 calories/day. You'd have to gain 20 lbs of muscle, basically become a bodybuilder, just to offset a KitKat. The math is pretty depressing.

In my experience, full body sports (krav maga in my case) are the exception here. It's super easy to stay lean if you eat normally and do this kind of thing. My explanation for this is that the body adapts very well to using a single set of muscles because it expects to have to do it for a long time, like when hunting or gathering, but full body means you are fighting for your life. I think this is also why lifting heavy works so well too. (I have no credentials or training in this area, just my own xp, so treat this as wild speculation of course.)

That's a common misunderstanding but efficiency doesn't actually change much based on exercise. You can verify this with metabolic tests that measure inhaled and exhaled gases.

Muscles don’t burn that much calories, only like 13 kcal/kg/day. So if I suddenly gained 10 kg of muscle, I could theoretically burn half a donut per day. Plus the extra calories spent moving those 10 kg of muscle around. But it’s not a free meal.

Agree 100%. The data on this is pretty depressing. There isn't much you can do but eat less. Even huge bodybuilders quickly get fat when they go off season. All that muscle evidently doesn't work enough to offset the appetite.

Gaining 20lbs of muscle, which would be quite a visual change, would only burn about an extra candy bar.

When I was mountain biking heavily I could eat whatever. You just need a Huuuuuge amount of cardio, haha.

Men with a lot of muscles in fact can and have to eat more to maintain their weight then men with less muscles.

That extra food in fact does include cakes and treats.

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