“Yamming it Up”
I've coined a term: "Yamming Up" which refers to adding small amounts of extra starch to meals for a day or two when I'm preparing for a race. Longer if it's an Ironman and shorter if it's a running-only race.
I always choose yams as my starch of choice. As those who've read The Paleo Diet for Athletes are aware, there is a place in a modern paleolithic diet for yam and/ or sweet potato- before, during (if applicable) and after endurance activity.
Even for those endurance athletes who do NOT follow a paleolithic diet, it would behoove them to eat yams in lieu of other 'sports nutrition' options when getting ready for their event.
Unfortunately, more sports nutrition products than not, feature ingredients that range from mildly offensive to downright unhealthy items that are simply not food! Have a look at some of the labels of the items on the shelf in your local bike shop or triathlon store and you'll see what I mean: malitol, sorbitol, wheat, oats, whey, artificial color and flavor, hydrogenated oils, fractioned oils, soy, peanut… it goes on and on.
Aside from the fact that inflicting these things (again, I hesitate to call them food) upon your body would be toxic and encourage a host of unfavorable consequences both short and long term, they are NOT going to help your race if you are sidelined with a stomach ache, feeling empty because you weren't able to properly digest what you've eaten for the past few days, or are experiencing an inability to sleep or joint pain (just a couple of the ramifications of eating grains, legumes & dairy!).
Give it a trial run the next time you have a B race coming up. Skip the bagels and peanut butter, the pasta loading and the 'energy bars' (aka candy bars). Even if you're performing phenomenally now, you'll never know how much better you could be until you try eating the way we humans we meant to eat!