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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.

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