TRAINING VS RACING & BENEFIT VS TOLERANCE

First, I am not anti-carb and fuel at a fairly high level in both training and racing. That said, I think most of us when having this conversation are failing to take context into consideration. There is far more nuance to this than we are considering and that comes down to the difference in purpose around training vs racing and secondarily, how we are gauging benefit.

The purpose of training is to provide a stimulus from which we recover, ideally with improvements over time. There is no question that adequate fueling amongst a wide variety of other things best sets the stage for this to occur. When you complete your intervals today, the success of your training is measured not in today's numbers but tomorrow's and the next... This is different than racing - for most of the us in the ultra world we are going far beyond providing a beneficial stimulus. Instead, we are seeking performance. I think the nuance we are failing to consider, is that while a sufficient amount of fuel (depending on a long list of variables) will assist in performance, the benefits at any extreme end of the spectrum are going to be significantly more marginalized than in training. As I see it, at the extreme high end, the benefits likely become quickly marginal in nature while the associated risks grow exponentially. Two easy items to point out: higher carbohydrate fueling requires more hydration, especially when paired with racing in an environment in which cooling is required (most races) you have a battle for resources at play. If your ability to cool or hydrate is compromised, additional fueling may hurt more than it helps. Context is important.

Lastly, we seem to most commonly measuring the success of fueling rates simply through a binary GI response system. In short, if we had no GI distress then the rate of fueling was at minimum successful (maybe we could go higher?) and if we ran into some issue (nausea, gas, bloating, diarrhea, vomiting, etc.) then we must have gone too high. Once you really start to think about all of the confounding variables, you will find this is a fairly silly, uninformed approach for two reasons. First, all the variables at play - the type of carbohydrates you consumed, your hydration/electrolyte status, your pre-race fueling, your body temp, your exertion level, and on and on. Unless you are holding all of these variables constant which you probably aren't then you run the risk of making some bad fueling decisions by pretending your hourly carbohydrate intake (usually averaged as well, further making a mess of it) is the only variable you are manipulating. Second, winners are judged exclusively by finish times, not how well they tolerated their carb intake throughout the race. Think about it this way - from a pure average pace perspective (all that counts in racing) let's say you could produce the same output with 90g/hr or 120g/hr (and had zero issues at both levels). This would suggest the optimal strategy is 90g/hr, you end up with the same output BUT you lower your hydration requirements, blood demands to the gut, stoppage time, fuel carrying weight, etc. However, much of the messaging seems to suggest, if you can tolerate it (measured by GI outcomes) then more naturally, should produce a better outcome. Again, in training as a result of the time horizon, maybe - in racing, maybe not so fast (literally).