To address your specific example: it strikes me that “mandating one meat meal a week” would be similar to “children aren’t allowed to ski”–that is, it prevents the possible injurious behavior entirely rather than mitigating the risks. The analogy isn’t perfect either way.
I’d be more on board with something like mandatory doctor checkups to screen for malnutrition on a regular basis, or provision for mandated caloric measurement and proper supplementing.
I’m not familiar with the laws in every state, but in most of the big skiing states the laws are written in such a way that it’s virtually impossible for ski areas to be held responsible for any sort of skiing injury. For example in my state (Montana), those “sign away your right to sue” liability waivers are completely unenforceable… unless you’re a ski area (the only exception).
I’m not familiar with the laws in Colorado, but in Montana ski hills that do summer activities have to be far, far more concerned about safety then because they actually could be sued for accidents that happen then. I would bet if they were similarly exposed to legal liability during ski season, they would definitely require helmets.
(BTW, I’m not saying the above is a bad thing since if you could sue ski areas for skiing accidents, their insurance costs probably would be prohibitively high. If anything, I wish similar rules would be passed about other riskier outdoor activities.)
I didn’t know there were specific exemptions for skiing. I wonder when/how these exemptions came about? If they are skipping all liability for injuries, I don’t see why imposing helmet limits is a problem. I mean, the ski areas already benefit from governmental restrictions on lawsuits and the hand that gives can take away as well.
Usually waivers protect from liability when there is negligence, but not when there is gross negligence. The difference between negligence and gross negligence is something that would be fact specific for each case.
Some states have specifically relieved ski areas of liability to a much broader degree. For example, the Colorado Ski Safety Act relieves ski areas of liability from dangers inherent in skiing. What constitutes a danger inherent in skiing would be fact specific for each case, but I expect that it would start carving a chunk out of what otherwise would be considered to be gross negligence.