Planning to spend fourteen to twenty one days at altitude before competing is not directly a nutrition consideration. It is however, worth mentioning because adjustment time can indirectly impact nutrition by altering appetite and, how the body feels overall.
Unfortunately, before some of my biggest mountain races I haven’t had the extra time to hang out high up. So I searched for clean short cuts of which I learned, are limited.
In short, there are not short cuts for adapting your body at altitude. It takes the time it takes. How much time it takes specifically will vary because, as with nutrition, how the body responds is individualized. Everything I have read says get to your altitude twenty-one days ahead of your race.
With work, kids, and other obligations it just isn’t realistic to get that kind of time at elevation (unless I move there!). So here are some the strategies that helped when time at elevation is limited:
Go up the night before if you can’t do two-three weeks! So save the PTO and head up the day before. Going up on five to ten days before puts the body into a race while smack-dab in the middle of the acclimatization process, which can be extra tiresome.
Push the training at sea level to get used to low oxygen. Talk with a coach about specific training to mimic low oxygen state so you get used to running through it. For me this looks like lots of stairs or hill repeats to the point of puking. Fun times!
Propose a telecommute option from altitude. If you have a job that you can take anywhere and the other humans counting on your presence are flexible, this can be a great option.
Convince the office to provide a hypobaric conference room. This is a long shot but, given the number of active people in my office who prefer to compete in the mountains, it is possible.
Convince spouse/partner to sleep with a hypobaric tent over the bed each night. I have never been able to present a convince argument or budget for this. I have also “heard” it is of limited value.
Drink up beet juice concentrate per usage instructions. Studies suggest it can help some with oxygen efficiency. I find it does help. It could be placebo, but does it matter?
The best option for me has been to accept that I will be slower, it will be more difficult, and slow my roll to enjoy the view from up there.