Weight-loss drug found to shrink muscle in mice, human cells

> emerging research showing that up to 40 per cent of the weight lost by people using weight-loss drugs is actually muscle

That's the sort of headlines that smells like bullshit to me.

My understand of those drugs is that they don't actually make you lose weight, they just cut your appetite so you can follow a diet to lose weight without hunger hammering at the door. So to start with, if that's the case, all they are observing is the effect of a diet. Not sure the diet drug has much to do with it.

Then I went from 133kg to 88kg with these diet drugs. Even though I exercised every day, I am sure I also lost some muscle mass as well, just because I don't have to carry 45kg every time I make a move anymore. Seems logical and would probably be concerned if it was any other way.

The next line of the article after that 40% quote:

> Carla Prado, a nutrition researcher in the Faculty of Agricultural, Life & Environmental Sciences and lead author on the commentary, explains this rate of muscle decline is significantly higher than what is typically observed with calorie-reduced diets or normal aging and could lead to a host of long-term health issues — including decreased immunity, increased risk of infections and poor wound healing.

The rather obvious problem is that these GLP1 agonists don't improve your diet. If you continue to eat a protein and nutrient deficient diet (which is probably a majority of Americans) with caloric restriction on top of that, that leads to excessive muscle loss that you wouldn't see in a weight loss diet. This normally doesn't happen without GLP1 agonists, because these diets are too difficult to stick to for most people. Those who stick to them usually turn to nutritious high satiety whole foods that help combat the negative effects of caloric restriction.

Losing weight without losing muscle mass is very hard. It requires extreme diets like a protein sparring modified fast where 80%+ of your calories are from lean protein while running a 50% caloric deficit. If this research is correct, then using GLP1 agonists shortcuts the feedback loops that make the diets hard to stick to, but they shift the tradeoffs from weight to overall nutrition.

"When a measure becomes a target, it ceases to be a good measure" and all that.

> The rather obvious problem is that these GLP1 agonists don't improve your diet

My understanding from initial anecdotes is this is actually literally wrong. Which was surprising to me, too. But people on GLPs tend to prefer more nutritious food (high protein and high fiber). I'm not sure if this has been studied directly in clinical trials yet but I know that food manufacturers have been reorienting their products toward healthier meal configurations in response to the GLPs.

I predicted the exact opposite of this, but so far I appear to have been wrong.

This observation is very interesting. I hope that it is studied more closely and we can read some peer reviewed research on the matter. One idea popped into my head: Could part of the cause be that people's mood and self-esteem improves during (GLP1 agonist-induced low hunger) weight loss? TL;DR: If you feel like shit about yourself (and body), then you are more likely to eat poorly, and vice versa.