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Comment by matthewdgreen | Hacker News Reader

Americans do more exercise than ever and have also reduced their sugar intake on average, but obesity continues to rise. Is it possible that food additives or something less obvious is having an effect? GLP-1 agonists are a good indicator that even minor chemical interventions can have a huge long-term effect on obesity that dominates diet and exercise, so why do we rule out the possibility of other substances doing the opposite?

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The statistics for those doing more exercise and those suffering from obesity are likely describing two different groups of people.

>Americans do more exercise than ever

Are they really? Fitness socials exploded in the last 10 years, many more enthusiasts training harder/longer, but I haven't seen noticably more bodies at the gym.

The number of gyms has skyrocketed in the past few decades, though. Back when the obesity epidemic really took off ca. 1980, "the gym" was a place inhabited primarily by bodybuilders and professional athletes. Regular folks were mostly doing calisthenics/aerobics, often at home following along with Jack LaLanne or Jane Fonda. Today, Planet Fitness is a ~5.5-billion-dollar company.

Which is why I'm curious about time/scale of effect, and what exactly is meant with "Americans do more exercise than ever".

One indicator is # of gym membership: ~30m->~70m in last 25 years, from 10% of population to 20%. Hard to say how much of that is due to gyms getting better at selling memberships because we know they oversubscribe. But per capita figures still suggest that vast plurarity of Americans, the average American, likely 1.5SD / 80%+ of population, probably don't have habit of regular exercise that would overcome effects of increasingly sedimentary life style. So should be ber surprising that obesity continues to increase.

I haven't been going to the gym in a while, but when I did there were a lot of people mostly looking at their phones and not doing much exercise. It was noteworthy when I ran on the treadmill that I saw other people actually running on them instead of merely walking.

I'd guess that many people going to the normal gyms aren't getting much out of it. Combined with the drive to and from the gym, and often getting a snack or something along the way, I have doubts that going to the gym is an efficient use of their time.

(the expensive, specialized gyms like Crossfit or climbing that cost much more are completely different)

Americans eat 25% more calories since 1961. It's that plain and simple, no need for monsters hiding under the food.

They also walk significantly less.

As a proxy, 47.7% of children walked or biked to school in 1969, and that fell to 12.7% by 2009. https://archive.cdc.gov/#/details?url=https://www.cdc.gov/po...

This mirrors general commuting changes in the Census.

My understanding is that GLP-1 affects appetite, and thus affects diet. And one of the reasons people quit GLP-1 long-term is because they miss eating and enjoying food.[1]

> The drugs work by activating GLP-1 receptors in the body in a way that reduces appetite, alters gut function, and may impact addiction pathways.[2] However, adherence to the drugs long-term is a challenge, as many people stop taking them after some time.

[1]: https://youtu.be/d3X3HPp44b8?t=951

[2]: https://youtu.be/d3X3HPp44b8?t=239

Right. There is clearly a powerful system in the human brain and body that controls our appetite and weight set point. Medications that adjust that system seem to produce durable changes in appetite and obesity, while typical changes to diet and exercise see weight revert to the mean after a year or so.

So the question is whether there are other substances in our diet that are also affecting this system. This isn’t crazy: various gut bacteria produce proteins that increase natural GLP-1 in the body. So any substance that disrupts these bacteria could easily have this sort of effect. https://www.nature.com/articles/s41564-021-00880-5

when you are walking everywhere for a few minutes at a time, it adds up rather quickly.

most americans who go to the gym spend 60 ish minutes there. they also usually eat something after.

i don't think it's food additives, because japanese are no stranger to mass produced food and beverages from food conglomerates. it's the country that gave us instant noodles.

> don't think it's food additives, because japanese are no stranger to mass produced food and beverages from food conglomerates. it's the country that gave us instant noodles.

And packaged convenience store food of all kinds.

Or just find out how many total calories they are eating, which is probably high.

The people who exercise and are obese are two distinct groups.

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