If you eat sports energy bars, choose the ones with 60 percent or more of their energy from carbohydrates. There are plenty of energy bars to choose from. Avoid zoning out.
From Running Dialogue's Nutrition chapter.
“The Zone” diet fad does raise an important point. This diet recom¬ mends only 40 percent of calories from carbos--leaving 30 percent from protein to overburden the kidneys and liver which either excrete it or convert it to sugar; and 30 percent from the artery-clogging fat. One of the arguments for the zone diets 40: 30: 30 is that we burn more fat calories sitting down than we burn carbos. Of course we burn more fat while sitting--but we use very few calories. It’s only true, because we are able to take in sufficient oxygen to burn an inefficient fuel...fat. When we start exercising however, the efficient fuel, sugar, provides most of our energy needs. Unless of course, you consume too few carbohydrates. The body will have no choice about which fuel to burn for energy. The body doesn’t become more efficient at burning fat and protein--it simply has no choice because it is being carbohydrate starved. Zone Diet argument two: 40:30:30 says carbohydrate makes the body respond by producing too much blood sugar. The body only converts raw material into sugar. The body absorbs the sugar from the consumed food, then efficiently stores it ready for use. If you consume most of your carbs as simple sugars, with negligible fat and protein at a meal, your blood sugar will peak a bit...then trough slightly (that sleepy feeling) as the pancreas (secreting insulin) tries to correct your cruelty. The sleepy feeling is not from low sugar--it will still be in the normal range--it is from the blood supply being diverted to your intestines, combined with the lassitude which occurs about an hour after returning to mundane tasks. Eat complex carbs, a little protein and fat to slow the entire meals intestinal transit time--and food absorption, including sugar absorption, will be steady. Some of the better tasting sports energy bars on the market derive 30 percent of their calories from fat. So much, in fact, that you may as well eat chocolate, plus a multivitamin after a training run. However, its 30 percent calories from protein is useful to keep the blood osmolarity up, and to give a ready supply of amino acids for immediate repair work. There’s a very simple way to correct the mere 40 percent carbos, and the overdose of protein and fat. We can dilute the protein and fat by eating two pieces of fruit. The complex carbos and fiber from the fruit, plus the nutrients from the bar will then be a balanced recovery snack to set you up for a meal about 2 hours later.
If you use sports energy bars, choose the ones with 60 percent or more of their energy from carbohydrates.
Or send $17.95 per book to David Holt at PO Box 543, Goleta, CA 93116. (includes shipping and tax)