Monday, February 22, 2016

"Re-Examining HF Diets for Sports Performance: Did We Call the ‘Nail in the Coffin’ Too Soon?"

Louise Burke is referring to this:

"“Fat adaptation” for athletic performance: the nail in the coffin?" (PDF)

From 2006. Do read the whole thing, but here's the summary:

"...It is tempting to classify endurance and ultraendurance sports as submaximal exercise, which might benefit from increased fat utilization and a conservation of limited endogenous carbohydrate stores. However, the strategic activities that occur in such sports, the breakaway, the surge during an uphill stage, or the sprint to the finish line, are all dependent on the athlete’s ability to work at high intensities. With growing evidence that this critical ability is impaired by dietary fat adaptation strategies and a failure to find clear evidence of benefits to prolonged exercise involving self-pacing, it seems that we are near to closing the door on one application of this dietary protocol. Scientists may remain interested in the body’s response to different dietary stimuli and may hunt for the mechanisms that underpin the observed changes in metabolism and function. However, those at the coal-face of sports nutrition can delete fat loading and high-fat diets from their list of genuine ergogenic aids for conventional endurance and ultraendurance sports. [Emphasis mine]"

We've now seen a few athletes pursing high-fat diets win races, set course records, and even set a world record in the 12-hour track event.

And to her credit as a scientist, Burke published the paper in the title of this post in 2015.  She revists the research that was available in 2006 when she published the "Nail in the Coffin" paper, and updates with research that has been done since then.  (This was published prior to the FASTER study being released, so unfortunately does not include her thoughts on that, which is a shame.)

After noting that:

"...As a contributor to the evolution of the current sports nutrition guidelines, which have moved away from a universal approach to any aspect of the athlete’s diet, with particular effort to promote an individualized and periodized approach to both carbohydrate intake and carbohydrate availability during the training phase... 
"...Indeed, modern sports nutrition practitioners teach athletes to manipulate their eating practices to avoid unnecessary and excessive intakes of carbohydrates per se, to optimize training outcomes via modification of the timing, amount and type of carbohydrate-rich foods and drinks to balance periods of low- and high-carbohydrate availability and to adopt well-practiced competition strategies that provide appropriate carbohydrate availability according to the needs and opportunities provided by the event and individual experience [, ]....

She goes on to conclude:

"The science and practice of these strategies is still evolving, and indeed, a final comment by this author on the current literature on LCHF diets for sports performance is that another reason for considering it incomplete is that the optimal ‘control’ (or additional intervention) diet has not yet been included in comparisons with fat-adaptation techniques. Future studies should investigate various LCHF strategies in comparison with the evolving model of the ‘carbohydrate-periodized’ training diet, rather than (or as well as) a diet chronically high in carbohydrate availability, to determine the best approaches for different individuals, different goals, and preparation for different sporting events. Considering that athletes might best benefit from a range of options in the dietary tool box is likely to be a better model for optimal sports nutrition than insisting on a single, one-size-fits-all solution."

So I guess the carbs-all-the-time "dogma" is dead. RIP.

"This article was published in a supplement supported by the Gatorade Sports Science Institute (GSSI)."

OK.  This is, from what I know, a very fair assessment of where the science is on LCHF sports nutrition.  She does not discuss race results, which is another shame, but at least she's open-minded.

From what I know, while there are a couple of athletes who say they pursue a ketogenic approach to training, and win races; the bulk of LCHF athletes do use carbs strategically, especially during races. It still remains to be seen if a keto diet is "better" in terms of pace during a race: I'm not aware of any evidence that it is.

But there are many ways to improve performance in a race.  If you don't need to stop as much to eat, or can stop for shorter times, you're performing better.  Even if your pace while moving is the same.  If you can avoid the common dietary distress and related stops, you're going to perform better.  And one common note is that recovery from events is much faster, which should improve performance over the course of a season, or on a multi-day event.  Then we have the example of Kilian Jornet, who eats a high-carb diet, but trains fasted (8 hours at a go!), and appears to have a peerless fat-burning capability.

Science moves on, but it's nice to see it move in what I consider to be the right direction.

I'll continue to skip the Gatorade, which gives me digestive distress!

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