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Comment by baybal2 | Hacker News Reader

Does anybody have the sane reaction as me?

I often feel much less hungry if I do some physical exertion than when I spend day more or less still.

Exact opposite here. I get much hungrier on days that I work out. I basically need to eat an extra meal to not feel ravenous. Not great for weight loss unfortunately.

Depends on the exercise. Cardio can suppress appetite for a time, resistance training not so much.

In my experience cardio only suppresses appetite for the duration of the cardio. So even running two hours a day (a lot more than most runners, including myself, do), there's still ~14 hours of day to cram calories in my face.

Depends on intensity. Vomiting after marathons and triathlons isn't uncommon, and intensity that's slightly lower than that can still induce nausea which can last awhile. Reactions to all sorts of training are largely individual I think.

> Vomiting after marathons and triathlons isn't uncommon

Those are long distance, race intensity efforts. Most workouts aren't going to be race pace and most runners for fitness aren't running marathon distances, esp. not for every workout. In my experience, the nausea quickly subsides once my heart rate drops below 190.

> Reactions to all sorts of training are largely individual I think.

Totally agree. I was talking about my personal experience (anecdotal).

After weight training I am always hungry like crazy. But try to stick to healthier snacks so it won't counter your weight loss as much :)

You and GP are saying slightly different, not mutually-exclusive things, that matches my experience:

For a good hour or two after the exercise, I'm barely hungry at all. Three or more hours afterwards, and I'll be far hungrier than I would normally have been at that time.

I think so, but I never really measured the actual amounts I eat, and what, in both cases. It also heavily depends on what you're doing when sitting still: using your brain actively for work for instance is going to require quite some energy in comparison with just sitting still and relaxing. AFAIK the brain's main energy source is sugar so my (completely unverified - it's hard these days to find the truth amongst the insane amount of dietary bs out there) assumption is that physical exertion needs / can use different metabolic pathways not requiring instant sugar intake.

Something related happens to me as well, during light physical exertion: even when I get hungry, I can just keep on going and after like 30 minutes I don't feel the hunger anymore, and can keep on going for a couple of hours more. That just doesn't work for me when programming/debugging: then I keep on being hungry and after a while just cannot think properly anymore (could be placebo/confirmation bias, unsure.)

> using your brain actively for work for instance is going to require quite some energy in comparison with just sitting still and relaxing

Does it? I've always wondered if this was the case but according to this post it doesn't vary significantly: https://biology.stackexchange.com/questions/839/how-does-the...

Now that's suprising, thanks.

There's a lot of metabolic and information-processing housekeeping that needs to be done regardless of what we are thinking about. Even the sleeping brain is quite active.

The difficulty of hard mental problems is not necessarily related to the physical work needed, even when we recognize that information processing is a physical process - for example, figuring out when to leave for a lunch appointment is not necessarily less physically demanding than solving a differential equation.

According to my Google research, "brain activity" is not a valid excuse for eating more sweet snacks.

Brain can work also on ketones. This is exactly what is the point of keto-diet. It resists as much as possible to switching in this mode, I have to admit.

There's a sweet spot of physical activity which optimizes energy expenditure:appetite. Too little or too much and your appetite is higher than your expenditure.

https://www.ncbi.nlm.nih.gov/pubmed/22855277?dopt=AbstractPl...

Has that sweet spot been quantified as a multiplier of resting metabolic rate? Would love to experiment around with that number.

The article seems to say that the 60-min cardio group had been closer to that sweet spot, but it's not very concrete about that assumption.

Nope, nothing makes me as ravenous as excercise. I’m also not trying to lose weight, so that might be a difference.

Definitely for some time (up to 2-3 hours) after the workout. If I'm trying to lose weight I'll deliberately work out before lunch or dinner so I don't eat as much.

I read that happens when you have just started exercising/working out, or when you do it irregularly. Something about sudden stress switching the body into survival/fight or flight mode.

When the exercise is regular, it becomes routine

I do. My personal feeling is that I use food for energy when not working out. When I work out I get energized and won't need to fill up with food as much to feel energized.

Could be primal and hormonal. A situation where you need to run isn't usually the same situation you should stop and eat.

> When I work out I get energized

After I work out I want to nap.

I feel that running suppresses my appetite somewhat. I have wondered if the bouncing of my gut produces feelings of being full, or even slightly irritates it.

No, but that's completely unrelated to the article, isn't it?

No, complete opposite. I lose weight (muscle glycogen probably) when I miss workouts, because my appetite decreases significantly.

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