Of course, our daily diet is paramount if we're looking to realize our potential. Speaking for myself, I tend to neglect "eating right" because it's a pain in the ass, and the delayed gratification of doing it is hard to make up for the reward of eating whatever you want. And of course, when we're young, we can get away with a lot. But as I near masters status, I really feel like by not paying attention to my diet, I'm doing my athletic career a disservice.
Now, this is not to say I eat terribly; my wife is a very good cook, and I think my regular diet is generally pretty healthy. I tend to eat out more than I should, particularly lunch during the week when I have days off, or late-night dinner working overnight shifts. Obviously my IPA consumption is higher than might strictly be considered "beneficial." But for the most part I eat fairly well. I know, however, that I'm certainly not using my nutritional intake to my advantage, not molding what I eat to benefit me athletically. I follow lots of sports, and the more I read about athletes as they age, the more I find that they are turning to different nutritional strategies to gain an edge and combat the effects of getting older. It might be eliminating sugar, or eliminating fat, or going vegan, or eating more protein. Whatever. It's clear that athletes who pay attention to their diet have an advantage over those of us who don't.
So as I approached this year and this racing season I started to consider my diet more critically, particularly with an eye toward weight control. Obviously the lighter we are, the easier it is to run fast over long distances. Keeping my weight in an optimal range for racing has become progressively more difficult in recent years. In college, I raced at around 135 pounds, with a BMI of about 21.5. (Most elite US distance runners have BMIs in the 19-21 range.) In the past few years I've tried to keep my weight under 145, which I've generally been able to do, and to sneak down near 140-142 for racing when possible, which has gotten much harder. I've had to resort to significant calorie restriction, or brief bouts of eating nothing but fruit, or--heaven forfend!--completely eliminating beer. All of which will work, in the short run at least. But none of that has proven sustainable for me, and my weight has kept creeping upward (aided by my lack of willpower), kept in check only by copious mileage.
Like everyone else in the ultra world, I've heard a lot in the past few years about low carb diets. If you're outside this fairly insular community, several ultra runners have had significant success with switching to high-fat, low-carb diets (LCHF), both at the recreational and elite levels. One of the most well known is Zach Bitter, the WR-holder for 12 hours and the AR holder for 100 miles, who follows the Optimized Fat Metabolism (OFM) diet, a LCHF variant. Intrigued by the success of Zach and others, as well as reports from friends of mine who have successfully switched, I did some reading on the subject.
Basically, LCHF diets work by retraining the body to preferentially burn fat instead of carbs. Since we have nearly twenty times the fat calorie stores than those of glycogen, if we can tap into those stores efficiently, we can perform much longer in a relatively carb-depleted state (as would occur during a long ultra), and therefore would need to take in much fewer calories over the course of a race--a huge advantage. Unfortunately on a standard diet, the body can't access those fat stores with enough efficiency to make it viable. But by restricting carbs and suppressing insulin release, we can, in time, ourselves to metabolize fat at much faster rates. The FASTER study, performed at UConn last year, has yielded some interesting preliminary results along those lines. (The investigators aren't exactly neutral observers, having been LCHF proponents for some time, but the data looks reasonable.)
So I decided to try it. Starting the day after RFTH, I started severely limiting my carbs. I'm not keeping close count, but I'm estimating my carb intake to be comfortably under the 50 grams/day that Phinney and Volek suggest; probably closer to 20g a day or less, with very few exceptions. My experience has been consistent with most of what I've heard/read on the subject. Without sugar, my energy levels have stabilized throughout the day; I rarely have intense crashes and keep a much more even keel. For the first several weeks--probably the first month--I ran like shit. I could do the mileage without a problem, but nothing fast; any attempt at a hard effort was pitiful. But after those first four weeks I feel like my running has returned to normal, and I've been able to add in tempo work, MP running, and some progression runs with good results. And for sure, the weight has come off. I've dropped nearly 15 pounds in the last eight weeks, back down to 137 and a BMI back near 21.5, which has helped the running immensely. It's certainly not for everyone, and as I've indicated above, I'm not suggesting that anyone try it themselves. The jury on LCHF--the jury on most dietary advice, believe it or not--is still most definitely out, no matter what the ADA would have you believe. I'm just reporting a cool thing that happened in my life for the past two months, which maybe you find interesting.
Will I stick to it long term? I don't know. It's not easy, and I do love my pizza and beer, both of which have basically been eliminated. Right now I'm in Black Mountain, NC, getting ready for another crack at the Mount Mitchell Challenge. This will be my first "fat-adapted" race, so we'll have to see how it goes. Certainly I don't think I'll be as religious about the diet after this race is over, but I may use it from time to time, or continue with it long term with some "cheat days" thrown in to maintain my sanity. A lot will depend on how it goes tomorrow, as well as the results of the bloodwork I'm having drawn next week. (Most anecdotal reports indicate that, perhaps counter-intuitively, LCHF helps your lipid panels substantially, but we'll have to see.) Check back next week for a report on Mitchell and pictures of the all the pizza and beer I plan to consume immediately afterwards.