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

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.

> 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.

I was with you up to here. In my experience it's easy to maintain a huge proportion of your lean tissue during a weight loss diet: Do some resistance training, get some protein, and don't lose weight too quickly.

There's no need to go to the extreme of a PSMF - which will still have you lose a bunch of muscle on account of being too big a deficit. If you can keep your calories reasonable while on a GLP1 agonist, there doesn't seem to be any reason you'll lose an exaggerated amount of muscle.