Intensity of the workout matters. When I go wakeboarding with my wife I build up a nice big appetite. When I go to muay thai I get pretty severe appetite suppression and sometimes have to force myself to eat.

The other thing is that if you track >>performance<< you naturally start caring about diet and lifestyle. So for people just trying their first 5k - I highly recommend tracking and setting time goals.

Nothing keeps me honest about my diet like performance

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tshaddox 2 days ago | parent | next [-]

Your examples sound like fairly short-term biological responses to intense activity, which are likely different than long-term biological response to a significant increase in daily calorie expenditure.

I've done a fair amount of wilderness backpacking. It's common to lose your appetite for the first few days due to the change in environment, schedule, activity, etc. But pretty quickly your body will realize this is going to keep happening and it's going to need to make up the extra 1000+ calories you're burning every day.

	▲	djtango 2 days ago \| parent [-]
		I've been doing muay thai for the best part of a decade now, the appetite suppression is always there

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jorvi 2 days ago | parent | prev [-]

That's the point of the study though.

If you workout harder than your baseline, you will burn more calories than your baseline.

But if you do that workout often enough, for various reasons you will return to baseline calorie expenditure.

This means that if you want to lose weight consistently, working out is useless in that sense. You might see benefits for 1 month or 3 months or 6 months, but eventually your body adjusts.

Working out is great for a plethora of reasons. And this calorie budget rebalancing is one of them, since it means inflammation or auto-immune responses get downregulated.

Losing weight is not one of those benefits. Whereas it is often held up as such which leads to intense disappointment and relapse with overweight people, because they think "oh, if I just go for six intense two-hour jogs a week, I can keep eating sumptuously."

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SirMaster 2 days ago | parent | next [-]

How exactly can your body adjust that much though? There is some minimum baseline level of calorie burn to stay alive and keep your body temp etc.

If you workout enough calories that exceeds the minimum baseline to keep you alive, the body can't adapt below that or adapt into the negative.

For a 200 lb man, jogging for 2 hours burns like 2000 calories, so that's 12,000 a week for 6 times a week.

What's the lowest a body will adapt to slow it's baseline metabolic rate? I am reading that the BMR can only reduce by like maybe 15-20% due to body adaptation.

This would put their baseline calorie burn at around 1500, and then if they are burning ~1700 a day from their jogging, they can eat 3200 a day to maintain or 3000 to even slowly lose weight over time, which is a decent amount that you can have a pretty fun "diet" of what you consume IMO.

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kelnos 2 days ago | parent | next [-]

> For a 200 lb man, jogging for 2 hours burns like 2000 calories

ogging a mile will burn around 100kcal, a bit more if you're decently overweight, let's be generous and say 150kcal. Someone who isn't in good shape and is overweight (the kind of person we're likely talking about) isn't going to be running that fast, maybe 3mph. So that's 6 miles in 2 hours. Even if I'm incredibly generous and say they'll burn 200kcal/mi, that's only 1200kcal. But in reality it's probably more like 900kcal.

But let's be real here. Your average (even above-average) overweight person with a not-so-great diet is not going to be jogging for 2 hours. Maybe they'll jog for an hour. So 450-600kcal. And maybe they'll do that 2-3 times a week.

1350-1800kcal extra burned every week is great! Except that still probably won't be what happens, exactly. Unless this person is also counting calories, or consciously working hard to keep their exact same diet, they will probably unconsciously eat more. Adding a 9mi/week jogging regimen to your life, especially if you're overweight, is going to make you more hungry than usual, so you will eat more. How much? Well, hard to say. Maybe enough so that you still end up with a calorie deficit, but in many (most, I'd guess) cases you'll still have a surplus, even if less than before.

This is all still a good thing! A 500kcal surplus per week when you're running 9 miles is much better than a 1500kcal surplus every week with no exercise. But this (hopefully) demonstrates that it's not as simple as "I'll just add some exercise and that'll get my weight under control". You need to change your diet, and take in fewer calories. It's hard. But it's the only way -- for the vast majority of people -- that this will work.

	▲	SirMaster 2 days ago \| parent [-]
		I never really found the eating more when exercising more that compelling personally. I mainly meal prep and eat the same amount whether or not I work out and how hard I work out. I feel like saying that someone is going to eat more because they are start exercising a lot is a separate topic. But I would think that someone who has the willpower to start exercising drastically more also has the willpower to control what they physically put in their mouth. I have personally found that stopping putting things in my mouth to eat is easier than getting myself to exercise as much as I would like to, so I don't think it's a guarantee that someone choosing to exercise more will automatically eat more.

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nradov 2 days ago | parent | prev [-]

For a 200 lb man, just jogging doesn't burn 1000 kcal/hr. You have to actually run at a pace of about 8:30 min/mi. People who can sustain that for 2 hours per day every day are not overweight in the first place.

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lukeschlather 2 days ago | parent | prev [-]

I lost between 50-70 pounds in a year, and I used a Garmin smartwatch which I wear all hours to track my calorie expenditure, which is pretty accurate. I think this effectively allows you to ignore the kind of exercise. You just keep track of your calorie burn. If your workout doesn't burn enough calories, you do more.