Why is any discussion about weight and running seemingly off limits now?

Good question.

How is it off limits? People talk about it all the time here.

Most people are fat and will never not be fat so it's pointless.

Here isn’t the entire running world?

Well women got the brunt of crappy coaches who gave them hell for weight. Also screwing around with weight really affects hormones in women more than men.

Where is it off limits?

Your question was about weight, but then you started talking about food. Which is it that you want to discuss? Eating unhealthy food does not necessarily make someone overweight, and vice versa. Restricting calories reduces weight. It doesn’t matter if those calories are healthy or unhealthy. Eating healthy food is beneficial as it contains vitamins etc. But this has little to do with weight.

A more valid discussion of weight in running probably looks at what level of dehydration you are willing to accept on race day.

But so many women would be faster if they lost some weight. Most people are overweight.

You’ll get no argument from me. But it isn’t worth a career to tell the female athlete that she needs to lose weight. And that’s exactly what it cost you. A male will be considered guilty until proven innocent.

The question wasn't really for coaches, just the average poster.

It's also because people tend to go too far with everything. Not everyone, but some people with mental problems. That's why you have to be careful with everything say online now days. Because with today's social media, anything you say could be heard by millions of people, and statistically there will be some small percentage of nuts who will take it way too far and do something stupid. That's just the nature of speech in today's world. So if you talk about weight there will inevitably be a few nutty women that will starve themselves to the point of damaging their health badly, or commiting suicide or some other extreme thing that most people have sense not to do.

Off the top of my head:

1. RED-S

2. Power to weight ratio.

Those might explain why it’s not a productive topic anymore.

as a more serious answer:

there is really no comparable performance enhancer like losing weight

for the majority of runners that aren't already/naturally extremely lean, it's more effective to lose significant weight than it is to use a gold standard oxygen vector substance like EPO

because of this fact, combined with women tending to be more attractive when on the leaner side in an otherwise obese world, women and girls are at somewhat extreme risk of compromising their health mostly unconsciously in the pursuit of athletic, social and sexual relevance/advancement

there are an order of magnitude more horror stories (almost every top female hs distance runner ever) than success stories (many successful female pros were not quite the best of the best in hs, though almost always very close)

the result is that discussion is highly censored, though i totally understand it's for the best intentions, even if i don't agree as it's my opinion ignorance only perpetuates the problem

Yeah, it's such a difficult thing to balance, especially with women. When you consider just how bad RED-S is and look at the percent of women distance runners who have had RED-S (40% iirc), and think about how many years of running have been ruined via that (stress# etc) along with reproductive health you quickly eer on the side of caution. Especially if interested in long term development where consistency in terms of injury and sufficient fuelling for adaptations is necessary. Men can afford to fly a bit closer to the sun but there are still risks, and it is so important to do it in a very slow and cautious manner.

With all that in mind I think it's generally discussed less these days as actively trying to lose weight has such a high risk of causing RED-S, whilst with sufficient training excess weight will naturally be lost.

Because a heavier man who does double treshold and 5 workouts is faster then an underweight man who does only 2 hard workouts.

The new trend in training is more quality work and optimal recovery, specifically tailered for the athlet.

Generic training plans and weight formulas are thing of the past.

Bigamy Johnny does not recommend 5 workouts a week. The athlete risks injury or overtraining, and may wind up slower than the athlete doing two workouts per week.

Because certain coaches trying to make a stick figure out of people like Mary Cain, destroying her health, self-esteem and overall self was not and will never be okay.