Comment by o10449366 | Hacker News Reader

Comment by o10449366 | Hacker News Reader

Parent Full thread

Drugs like Adderall don't mimic the hormones talked about in the article, right?

I took Adderall XR once a day in college which completely suppressed my appetite and, combined with being a poor student that couldn't always afford lunch, I would frequently only eat one meal a day (either breakfast or dinner.) Since I graduated college many years ago, I also stopped taking Adderall but my sense of hunger has never returned. I always figured my body just got used to having my appetite suppressed and now I can go multiple days without eating and not feel any physical sensation or side-effect (including fatigue/irritation from lack of food or things like headaches.) Just the other day I went 40 hours without eating while traveling for the holidays and didn't even realize it until I went to a social dinner.

I've never thought too much of this. It seems like in pop culture/science nowadays "fasting" is generally seen/understood to be beneficial. I certainly don't mind because its helped me stay at a healthy weight, but in reading about this new class of drugs for weight loss recently I am curious as to what exactly is going on in my body and whether there's a similar mechanism at play.

Is there anyone who fasts regularly who's also experienced this loss of hunger sensation?

I'm also one of those people who finds it more convenient to eat 1 meal per day when busy. It also started in my early 20s, but I've never been on stimulants. I got in the habit of eating irregularly in grad school which made it even easier to continue. I rarely have any appetite within an hour of waking up, and ive almost never eaten during this window. Not clear to me which is the cause vs effect.

I know some people who are on the opposite end and have problems functioning after missing lunch. None of them have ever intentionally fasted, though again it's hard to separate cause from effect.

What is clear is that different people's bodies form very different expectations surrounding food intake, and we are mostly unaware of this collectively.

No Adderall works via a completely different pathway.

Not at all, nor do all prescribed users of Adderall experience any change in appetite.

> Adderall increases the level of serotonin in your body, which can cause your appetite to decrease, leading to weight loss. This can be a good thing if you are trying to lose weight, but it can also cause stomach pain.

Adderall and other stimulants activate the chemoreceptor trigger zone in the brain and that can mediate feelings of hunger, nausea, trigger vomiting etc.

To add to this, stimulants can release dopamine or even bind to dopamine receptors in parts of the brain responsible for emesis, which the CTZ is part of.

Adderall might lead to downstream raising of serotonin levels, but the drug itself doesn't act on serotonin and I'd be genuinely surprised if the emesis symptoms it can cause were mediated by serotonin and not the dopamine it acts on.

Drugs that block dopamine receptors in the CTZ, like compazine, are regularly prescribed as antiemetics.

Low metabolism perhaps?

I suggest reading the new book, Burn: The New Science of Metabolism.

Low metabolism tends to cause weight gain, so probably not. Iirc, people with low metabolism eat more to get their energy levels and/or temp up high enough until their weight gain brings up their metabolism to a more normal range.

There's a lot we don't know, but from what I gather microbiome tends somewhat towards homeostasis such that you tend to eat in a way that maintains the current status quo. Among other things, this is linked to things like whether or not you are at risk for obesity.

Reply on news.ycombinator.com