It is no secret that sugar is the most effective fuel for endurance training. But are they the best? Some people disagree.
I am a fan of eating everything. I am not going down the rabbit hole of high carb, high fat, vegan, organic, gluten free fads that persist in adding confusion around what fuel is best for athletes. What I am dealing with here is sugar. Specifically, the confusing, even contradictory messaging about endurance athletes and the sugar intake.
I’ll begin with a simple, basic point. Whether or not you agree with consuming sugar during exercise, there is ample evidence that sugar is a root cause of America’s ongoing health crisis. Sugar is not the only culprit, but in my opinion it is at the top of a short list. It is not OK to grab a bottle of Gatorade at Seven-11 just because you are thirsty. Same goes for soft drinks. The ones with real sugar are bad because of the sugar, and the “diet,” “zero,” “sugar free” varieties are just as bad due to the chemicals.
Sports drinks got their start as an improvement over plain water. The improvement came in the form of electrolytes, the theory being that a drink containing sodium would do better at replacing sweat. The problem was taste. The early attempts tasted like brackish sea water and nobody would drink it. As they say, a spoonful of sugar makes the medicine go down, and in the case of sports drinks this was certainly true.
Fast forward a decade or two and you find a market filled with an array of sports drink products. In addition to sugar infused drinks you find semi-liquid gels and more-or-less solid chews, all designed to deliver a sugary punch.
Scientists knew that the body uses two forms of dietary sugar, glucose and fructose. Some products claimed to be superior because they used one or the other until new research showed that the best results come from using both. The latest research shows that the body stops processing glucose at about 60g/hr. If you want to get past that point, say 120g/hr, you have to rely on fructose for the extra energy.
Why do we want 90 or 120 grams of carbohydrate per hour? The more we absorb, the less we rely on our precious, limited stores, most of which is in the liver. Race results have demonstrated conclusively that these high levels of carbohydrate, especially on the bike, have a significant impact on performance. Elite athletes aim for 120g/hr. Age groupers can get by with 90. Those levels must be reduced on the run to avoid gut issues.
If you go out on your bike tomorrow and consume 90g/hr, it won’t be long before you puke. Your brain is not used to such a high rate of carbohydrate consumption, and will do its best to protect you from what it thinks is a threat. These high levels of carbohydrate intake require training, in the form of gradual increases. This means that every week, on the day you do your long ride, you need to consume the same type of fuel you will use on race day, starting at 60g/hr. and slowly increasing the dose.
There is evidence that a diet high in sugar can lead to a variety of undesirable effects. Tooth decay, for one. Weight gain should not be an issue because you are burning as much or more than you consume. Even so, the long hours spent with high levels of sugar circulation through the body can lead to a variety of health issues. I am no expert on this topic, so if you want more details please listen to this podcast by Trevor Conner at Fast Talk Labs.
My point here is the discrepancy, and associated confusion, between polar opposites. On the one hand we are told that consuming 90 to 120 grams per hour of carbohydrate is essential for good long distance events, and that the only practical way to achieve that intake level is to use a mix of sucrose and fructose. To put it simply, sugar, dissolved in water or in gels or chews. To reach those levels we must train our gut by practicing this fueling on our long rides. On the other hand, straight sugar is bad for us, and we need to provide carbohydrate in other forms, such as rice cakes. So, which is it?
All I can suggest is that we balance carbohydrate intake in the base season, and start the high dose sugar training at the start of the build period. Everybody is different, so it may take a couple of these cycles to dial in what works for you.
Personally, I find Precision Hydration to be an ideal source for high sugar content fuel. I have had good results with their PF 300 Flow Gel on the bike, and PF 90 Gel on the run. For short workouts of 45 to 120 minutes I use their PF 30 Gels.