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Comment by oxfordmale | Hacker News Reader

Exercise doesn't result in changes in body mass (weight loss), unless accompanied with a diet.

https://www.theguardian.com/science/2016/jan/28/study-reveal....

Like the saying goes, you can't out-train a bad diet (unless you're a complete outlier like Eddie Hall or Micheal Phelps or DK Metcalf).

This is a good podcast on the topic as well: https://www.artofmanliness.com/health-fitness/health/new-sci...

Reading about the diet of DK Metcalf that is Low carb, Intermittent fasting, with plenty of vegetables is according to the latest science. Eddie Hall has goal based diets, Normal people wouldn't be able to process the amount of food he eats, can't be healthy to eat that much. But at the same time it's clearly working for him. Just saying genetics does a disservice to them.

Intermittent fasting contributes nothing to weight loss beyond the psychological effect, which may result in calorie restriction. This is the latest science.

Calories concept is from 1819.[0]

Are you aware how calories are measured?

[0]https://en.wikipedia.org/wiki/Calorie

How can a diet both be plenty of vegetables but also low carb? As far as I know basically all vegetables are 50~70% carbs.

Low carb diet is about lowering the amount of carbs someone consumes, only some vegetables that have many carbs or starches are best to avoided, because they have more then 60% of their content in the form of carbs vs less then 10% for other vegetables. on the list to avoid, or eat limited amounts are Potatoes, rice, grains.

For example: Broccoli has 6 gram of carbs per 100 gram vs rice that has 80 grams of carbs per 100 gram.

I think they are genetic outliers, but they are also outliers in the stresses they are putting on their body. They genuinely need ~12k calories per day (Hall and Phelps).

They are genetic outliers because are able to operate at a elite level, but if you would learn more about sport and nutrition then those diets wouldn't look so extreme. They are eating goal based diets, that's different diet then normal person could or should consume. Hall and Phelps diet is not one that very sustainable but Metcalf one is actually the quite similiar to longevity diets. As such statements about that they are just genetic freaks this a disservice to diets they are eating and what we can learn from that.

If they would 4k their bodies will start to adjust to those levels, would that be their top performance probably not. The human body is very adaptable to any kind of circumstance.

I don't think Eddie Hall is a good example of being able to "out-train a bad diet". He eats and trains for one very specific purpose - to get stronger. His physique reflects that. He's pretty fat, don't let his visible abs fool you.

I've met him, when he was 3 times UK strongest man before winning WSM. He most definitely was not fit for daily life but was in good shape for strongman.

By saying "out-train a bad diet" I mean he needs his reputed 12k calories to build and repair his muscle mass (obviously some went to fat as well). The people on "America's Fattest People" (or whatever) don't need 12k calories a day and get (the bad kind of) huge as a result.

This is nonsense. Try running 70 miles a week on the same diet and see if you weight the same after a few months.

I can't abide this line that it's all about diet. I'm a big guy >270lb. When I moved in 2017 I was living 4.5 miles away from my job down this beautiful disused old railway line. "Jogging" and eventually running the 9 miles a day to get to and from work caused me to lose 80 lbs. Stupidly once the weight was off I bought a car and stopped and over 3 years the weight came back. So much of this stuff is whether you were conditioned from childhood to be active. You can change that, but you probably won't do it on a treadmill in a gym a couple times a week.

Yes it can. I had an injury that prevented me from cycling for over a year and slowly gained weight. It all came off after resuming a normal routine without dietary changes.

Well whether you lose/gain weight depends on (caloriesIn - caloriesOut) it's no rocket science.

If you didn't compensate anymore as much for lowering the calories out you're obviously going to gain weight.

So what you mean is your original comment could just have much said "exercice results in weight loss unless accompanied by a corresponding change in diet to increase calories intake", aka exercise alone as a change results in weight loss.

People get hungry after exercise and automatically eat more to compensate for the spent calories.

If you start exercising, but don't watch your nutrition, you will most likely not lose weight.

I don't get why folks often need to reduce such a complex and unique system as our body and its metabolism into some few word description.

You are correct, and there is more, much more: psychology, how our body adapts to training, and so does metabolism. One random example of this vast topic - its well known in weightlifting community if you do hard compound exercises near your limits (squats, deadlifts etc) your metabolism switches to 'higher' burn rate (basal metabolic rate IIRC) and you can basically consume more. One sure way to lose weight if thats the goal, but one should never start weightlifting with those exercises, at that intensity.

Also, again generally, its pretty non-smart to take sedentary individuals and expose them to HIIT as the study did, even if its just spinning. Body should gradually adapt to workload (=stress) and HIIT should be the final step in training, since its so taxing. Otherwise injuries and lose of motivation will happen more often than not. The systems that need adaptation are numerous - muscles, tendons, ligaments, cardiovascular system, nervous system etc.

People are just looking for quick solutions to problems that don't have ones, not good long term at least. Same as diet fads. The cold hard truth that permanent change of fitness/BMI/overall health for the better requires permanent change in nutrition, training and TBH at least a bit overall life approach. Why not start with that?

>People get hungry after exercise and automatically eat more to compensate for the spent calories.

This isn't universally true.

Exercise significantly decreases my appetite for about 3 hours post exercise. And for me, it's not just a barely noticeable decrease - it's an extremely noticeable long-lasting appetite decrease where I'll often end up skipping meals.

Do a quick google search for "exercise decrease appetite" for supporting evidence.

During the exercise the body is in a state of flight or flight[0], the other mode is rest and digest. So during hunger will go away, but the body will want to be able to exert the same or more(because that amount was at least needed), and as such it will start fighting against rapid weight loss by exercise, by increasing hunger, and or slowing metabolism.

The reason why this is quite simple, body is unable to see the difference betweenexercise and staying alive in a hostile world. As such staying alive will always be prioritized. If CICO would work then we wouldn't be obesity pandemic[1]

[0]https://en.wikipedia.org/wiki/Sympathetic_nervous_system [1]https://pubmed.ncbi.nlm.nih.gov/28292617/

That sounds neat.

For me, after I exercise, I get ravenously hungry and am unable to concentrate for the rest of the day unless I eat a 3-5k calorie meal. I heard it would get better over time, so I did it for a year, one hour with a really good personal trainer, three times a week. It put a lot of strain on my relationships, and I got in trouble at work since I was basically at half capacity, and couldn't get any work done on Mondays, Wednesdays, or Fridays. I did it for a year and it was the same the whole time. I was also told that eventually I would get "addicted" to exercising, but I hated every moment of it up to the very end.

After a year of that, I stopped, and regained my sanity for the most part. I didn't actually lose much weight, but towards the end I had gotten some compliments about looking healthier, which was nice, but not worth the psychological tool it took on me. I guess I'm just sitting here desperately trying to not destroy my body further while I wait for some miracle cure for leptin resistance or something.

That's rough.

3k-5k calorie meal? That's an entire day's worth of calories, for someone really active. Strange your body didn't adapt.

3k-5k calories is 3 big burgers with fries, or two pizzas.

If GP is eating that much, they are very overweight. You don't burn that much calories during exercise, unless you are running a marathon (which I would not recommend doing 3 times a week).

3k-5k isn't a normal day, it's what happens during a binge. I would almost never do that after a workout, I would usually just writhe in pain from the hunger for the rest of the day. I rarely go over 2k calories during a normal day, but after a one hour workout, 2k calories doesn't even slow me down.

Interesting, thanks for following up and sorry for making assumptions. It seems we're all different. After a one hour workout I do get hungry, but not that hungry. I wonder if it's just different between people, or if the type of workout makes a difference -- I usually run or ride a bike at medium intensity, maybe it's different if you lift weights or do something more taxing?

I would be writhing in pain if I attempted to consume 3-5k calories in a sitting. I consume a lot of calories on basis that I also burn a lot cycling, but nowhere near that in a sitting. Even 5k/day for me would be painful.

I can consume 3k a day eating clean, but no more.

Eating all that in one meal would require some extremely unhealthy eating, for me.

I know sumo wrestlers and other extreme athletes are capable though.

First, this heavily depends on how exactly you exercised and on your actual diet. Bulking makes you hungry. Mild cardio or runs makes you less hungry and less likely to just eat crap.

Second, your body is rebuilding and healing itself from micro injuries, so eat proteins if you are hungry at that time. That does not mean your dinner then has to be exactly the same as before, you just have to shift when and what you eat.

A part of that weight gain is caused by no longer burning let's say an additional 500 calories a day from cycling, another part is due to lack of activity and muscle atrophy lowering your base metabolic rate. And all of this accounts to one thing: you eat too much for a sedentary lifestyle. Cycling just allows you to compensate.

So, sure, exercise helps at a certain point. But, take into account:

* If you're fat, your base metabolic rate is insanely high. Obese people are easily at 3000+ calories needed _just_ to maintain that mass.

* If you're fat, it's going to be almost impossible for you to do sessions where you burn 500 calories, simply because you're out of shape and possibly exercising injures you. Running isn't exactly good on your knees if you're overweight. Realistically, you'll do 200-300 cal sessions, at best, every day.

* If you're fat and you manage to burn these 500 calories... Good job, but that's less than 20% of your daily intake. Not eating something is infinitely more simple and efficient.

Our bodies are incredibly efficient at exercising without using lots of energy. Unless you do it for long and hard enough that you reach huge numbers of calories burned, diet is the most important component of losing weight.

That simply isn't true. Unlike running, cycling at an low endurance pace is quite gentle on your body. Reaching 500kcal/session isn't going to be a problem after a few weeks of getting your mind and body accustomed to biking for more than 15-30 minutes, and chances of injuries will be quite low, especially if you use a stationary bike. You can hit 400kcal in an hour of biking without too many issues. Larger people will generally put out more power and therefore burn more calories.

It's 'basal metabolic rate' not 'base', and it's not going to change materially over a year, even with a shift to inactivity.

Muscle atrophy from not maintaining exercise for a year will absolutely make your BMR change. In the same way, spend a year at the gym lifting weights and your BMR will absolutely go up, even if at the same weight.

Change, but not materially, maybe 5% or something that doesn't really move the needle like the claim of 500 calories.

> It all came off after resuming a normal routine without dietary changes.

well, doh, if you eat the same and use less you will gain mass. It's not because (lack of) excercise, it's because diet not fitting lifestyle

Excercises help in burning more calories so you can actually eat some tasty food from time to time without getting fatter and not going crazy from eating only low calorie stuff and that's about the only effect for weight loss...

I think what the parent meant by "no dietary changes" is that they didn't have to exercise any special discipline over their diet.

If I'm exercising regularly with sufficient intensity my appetite will go up, yes, but I still lose weight. For me, when training, keeping weight on is the dietary challenge. It's hard to eat enough!

I think it’s safe to assume that many inactive people start to exercise because they believe it will help them lose weight, however

I find changing diet much easier when I'm also workig to get into shape at the same time.

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