jcaweiioj fd; wrote:
Weight is definitely a tricky issue for a coach (in any era). The hard fact is that, all else being equal, lighter is faster. The hard part is keeping everything else equal. You want to be as light as possible while maintaining relevant muscular power and your body's ability to recover and repair itself (to advance fitness and avoid injury). In other words, weight is important, but it is part of a bigger picture.
I think a lot of coaches either only talk to their athletes about weight and not the muscular, fueling and recovery issues that can come with calorie restriction (as many anecdotes in this thread show) or they don't touch on it at all. Just indicating to driven athletes that they will perform better if they lose weight will inevitably lead some to destructive behavior and eating disorders. Not mentioning it at all fails to address a component of having athletes perform better and reach their potential.
I've encountered a few coaches (I'm sure there are more) that do talk about the issue with their athletes comprehensively. They make sure their athletes know and understand that unnecessary weight hinders performance, but they also stress the importance of fueling properly for runs and recovery. They stress that their athletes should eat plenty of nutrient-dense foods, especially vegetables, but get plenty of healthy fats, protein and quality carbs as well. If you eat enough of these things, you'll be well-fueled, and actually won't still be hungry and are unlikely to fill up on calorie-dense junk. Their message in the end is that a nutrient-dense diet and an appropriately hard training program will lead your body to a lean, healthy and sustainable weight, which in turn leads to good long-term growth and performance.