Total rubbish. Look how thick some of the top us runners are.
Elle st purrier etc. Light isn't always better.
Even fisher has some mass you don't normally see
They look that way compared to the field. Compared to a normal person, not so much.
I see this over correction to weight as being just insanely silly. You cannot be fat and you cannot carry extra weight and expect to be the best runner you can be.
Like others have said, in college it would seem that this would take care of itself. You have young talented runners, logging more miles than they have ever run, and they have the benefit of the training table. The only time weight would be a factor is if you are injured.
Many of the best middle distance runners and even some of the long distance runners are marked by muscle and enough fat to be healthy-looking. Middle distance runners like Rudisha, Jim Ryun, Elle St. Pierre, El Guerrouj, Josh Kerr, Jakob Ingebrigtsen, and many more have strong legs and enough muscle to be able to go fast with less effort. It's a balance, but some muscle is an advantage.
I'm surprised by any need to focus on weight for college runners. Between youth and high volume training, weight seems to take care of itself except for the occasional guy skipping runs or getting some crazy ideas about lifting weights.
I think we've all known (of) college stars with crap diets.
For most runners, this is probably true. I avoided soda and desserts and other such obviously bad-for-you stuff when I was in college but otherwise didn't think too hard about what I ate, precisely because I was running so much and figured, correctly, that I'd maintain weight that way. I suspect the issues arise among those who are almost but not quite at the level they want to be, especially those who are so close to the top but not quite there yet: for them there's a lot of temptation to do literally any little thing that might get them to the top, and if you've trained like a madman or madwoman and aren't quite there yet, it must be tempting to try some extreme things as far as diet. "If I train just like I am, but was five pounds lighter..." And once you're on the train of questionable eating and fueling, it's hard to stop. Five pounds becomes 10 pounds, etc. etc. And as others have said, it's hard for a coach to know how to approach weight issues and how to tell an athlete they need to lose pounds without insulting them, intentionally or not. Doubly fraught for a male coach discussing this with female athletes, for all the usual reasons that cross-sex talk can be fraught.