I’ve always had problems finding foods I could eat before exercising. I’ve tried crackers, cereal, granola bars, and just about every energy bar on the market. For years, PowerBars were the only thing I could eat right before working out that wouldn’t result in an upset stomach. And so for well over a decade before every swimming/rowing/whatever practice, I’d eat half a PowerBar and a bottle of water.
This worked ok, except for two things: 1) I’d still start to feel drained at the end of a long workout because it just wasn’t enough food and 2) I got really really sick of vanilla PowerBars.
Fortunately, someone invented energy gels, which are gentle enough on my stomach that I can eat them without any problem, even while I’m working out. The downside is that I’d like to be eating one or two an hour while I’m exercising, and at $1-$2 a packet, that starts to add up.
So I looked into making my own, and it turns out it’s not hard.
Basically energy gels/bars/drinks are just a delivery system for sugar, which your body turns into glycogen to power your muscles. But it’s not quite as simple as just eating sugar, for two reasons.
First, if the sugar is absorbed too quickly, your body will produce an excess of insulin trying to balance it out. You get food comas after large meals for precisely this reason – the simple carbs and sugars in white bread/potatos/pasta/desserts get converted into sugars, leading to an insulin spike, leading to a sugar low, leading to you falling asleep at your desk. (See my post Food Comas and Second Winds for how I eliminated food comas from my life.)
Second, the stuff in your stomach must be absorbed at the right osmotic concentration. If there’s too much sugar and not enough water in your stomach, your body has to use its own water reserves to dilute the mixture so that it can process it. That’s why all gels and energy bars tell you to consume them with water. An excess of simple sugars like sucrose or fructose are often responsible for gastrointestinal (GI) distress during exercise.
Commercial energy gels/bars/drinks designed for consumption during exercise are generally based around maltodextrin, a complex carb that is rapidly converted to glucose. It is absorbed into the body very quickly (high glycemic index), which is good for quick energy. Many products include fructose as well, a sugar with a much lower glycemic index. The idea is that as a slower-absorbed sugar, fructose can balance out the insulin spike from the maltodextrin.
Clif Shots (from the makers of Clif Bars) are one exception. They pride themselves on using all natural ingredients, and so the shot is mainly brown rice syrup, which contains both low- and high- glycemic index sugars (about half maltose, which has a high glycemic index and is quickly converted into glucose, and half complex carbohydrates, which are processed more slowly).
So I went to my local natural organic supermarket and picked up a jar of brown rice syrup ($6, 1920 calories) and a bottle of agave nectar ($5, 2100 calories, 90% fructose). I also went by a home brewery supply store and bought a pound of maltodextrin ($3, roughly 1700 calories). Most gel packets cost $1-$2 for 100 calories, so it’s a significant savings (along with knowing exactly what I’m eating and why).
The proper proportions for mixing these together depends on who you ask. PowerBar says you should consume glucose and fructose in a 2:1 ratio, the logic being that your body has two different intestinal transporters for the two compounds, and so if both sugars are present you can absorb calories at a faster rate.
Hammer Nutrition, on the other hand, recommends consuming only maltodextrin with NO simple sugars added. Their argument is that complex carbs can be absorbed in a solution of 15-18% osmolality, vs. 6-8% for simple sugars like glucose or fructose. A solution of complex carbs is therefore superior because it can be more concentrated, allowing more rapid calorie consumption. Hammer Nutrition claims that adding simple sugars increases the solution osmolality to a point beyond where either compound is efficiently digested.
Who’s right? I don’t know. I’ll be experimenting over the next few weeks to see if I can actually tell the difference. I started today, eating just brown rice syrup on a 30-mile ride. (I added a dash of vanilla extract, it actually tasted pretty good.) I felt good for the whole ride with no GI problems at any point, though I did notice that I had to pee way more than usual. I don’t know if I can attribute it to the brown rice syrup, but I’m happy that I found something cheap I can eat without upsetting my stomach.
I’ll stick with the brown rice for a week, then try using just maltodextrin to see if I feel a difference. If I’m feeling adventurous, I might try fructose for a week after that, though that’s likely just asking for stomach issues. A 2:1 maltodextrin to fructose mixture would match PowerBar’s recommendation, so that’s on the horizon as well.
