Digesting the Bar Facts continued...
Hertzler found that the Ironman PR Bar provided increases in blood sugar levels that remained fairly steady, which could translate into enhanced performance for endurance athletes. By contrast, the PowerBar produced a quick rush of blood sugar, but it was followed by a rapid decline -- not much different than occurs with a Snickers bar.
The composition of the Ironman PR bar -- 40% carbohydrate, 30% fat, and 30% protein -- may have been responsible for its more sustained effect on blood glucose, says Hertzler. For endurance events, he "research shows that consuming a little bit of carbohydrate every so often during a race is going to improve performance."
Nutritionist Nancy Clark, MS, RD, points out that anything that provides calories will give you some energy. "Bananas give energy," says Clark, director of nutrition services at SportsMedicine Associates in Brookline, Mass. "Twinkies give energy. Energy bars give energy. That's because they all provide calories."
Food vs. Bars
Most nutritionists emphasize that even when consuming nutrition bars, don't let them crowd whole foods out of your diet. For a quick snack, you may be better off eating an apple or a banana. Before an athletic competition, says Hertzler, "a bagel or graham crackers can produce a response in blood glucose levels similar to some energy bars, and they cost a lot less."
Though nutrition bars are handy, Applegate says that you may be overrelying on them if there's a growing pile of wrappers in your car. "Some people go to Costco and buy boxes of energy bars, and feel, 'I'm doing a good thing by eating them,'" she says. "They may think that these bars are better than food. But there are ingredients in foods that are missing from these bars. Just as you wouldn't want to live only on peaches or only on tuna sandwiches, you need a lot more in your diet than just energy bars."
Instead of a nutrition bar, Jackson says you can choose an alternative snack like a container of low-fat yogurt with high-fiber cereal sprinkled in it, or a fiber-rich bagel with a tomato and a small slice of low-fat Swiss cheese melted on it.