Originally Posted by ts01
“Eat food. Not too much. Mostly plants.” (Michael Pollan)
"Mmm, beer." (Homer Simpson)
That is all.
Actually, a number studies, over many years, have shown pretty dramatic increases in endurance for sports like cycling, running, etc (with an indication this applies to sprint-and-jog sports like soccer)-- with caffeine use prior to the activity.
When I was playing soccer competitively, I made a habit of coffee about an hour before a match. That gave me enough time to get the jitters out (I was caffeine naive), to pee, to stay hydrated. Anecdotally (which doesn't mean much), I felt like I had more oomph at the end of matches. But, honestly, it was most likely placebo/suggestion/false impression on my part.
I still stand by the idea that eating a round diet is enough, unless you're a world class athlete fighting over thousandths of a second. In which case, a "round" diet isn't enough-- nor are off-the-shelf supplements with questionable (see: potentially dangerous) side-effects if they're pure, and many of which, when tested by reputable, neutral labs, have been shown to have shocking amounts of impurities (from pretty inert shit, to heavy metals and other highly toxic substances, to prescription pharmaceuticals). If you're a world class athlete-- no, that doesn't include ski bums who get on the mountain every skiable day of the year-- you work one on one to tailor your diet to your body composition, sport, and other factors. You train at different elevations. Adding supplements might make sense, from a scientific angle, for a specific activity, where a world class athlete is right at the edge of physical performance-- when repeatable performance can test the benefit of the chosen diet/regimen. And then there's the illegal shit, like steroids, amphetamines (and other stimulants; see: most sports pre-last quarter of the 20th century, or current day U.S. Air Force long-range bomber pilots), EPO.
For those interested in why I say even seemingly innocuous substances (antioxidants such as Vit E, say) as supplements (and not via normal diet) can be dangerous, I suggest a quick glance at the literature. The Cochrane reviews-- which, like all studies/meta-studies, has weaknesses-- is a good place to start:
Conclusion: Supplementation with antioxidants, in healthy and unhealthy subjects (comparing many, many studies), didn't improve mortality. With most of the antioxidant supplements considered, notably Vitamin E, taking the supplements increased mortality.
As for me: I drink coffee to wake up these days. So yeah, that's about the limit for my performance enhancement... being able to function at all in the morning.