Having a beer the night before a race is probably OK, but don't look at it as part of your pre-race nutrition plan.

Is drinking beer a good way to carbo load the night before a race? – Ken

Okay, first a confession. Ken is a clubmate of mine, and he posed this question about carbo loading with beer on behalf of most of my Cal Coast Track Club masters clubmates—many of whom I’ve seen take this question out of the realm of the hypothetical and put into actual practice. So I’m sorry, Ken, but I have some bad news.

First, alcohol is not a carbohydrate (or a fat or a protein). It’s alcohol. A beer has about 12 grams of carbohydrates. Each gram of carbohydrate contains about 4 calories of energy. Alcohol has about 7 calories per gram, and a “standard” drink (12 oz of 5% alcohol beer) has 14 grams of alcohol. So most of your beer calories are alcohol—two-thirds or more!

Most alcohol gets broken down in the liver. This is important. Because while your liver is breaking down alcohol, it’s neglecting its normal duty of maintaining your blood glucose levels. When your blood glucose levels drop, your muscles start burning stored glycogen (increasing stored glycogen is the whole point of carbo-loading), leading to reduced glycogen levels—in turn leading to reduced running performance.

Alcohol simultaneously interrupts the metabolizing of other important nutrients. And it inhibits the release of a hormone (ADH) that regulates urination. For every 10 ounces of beer you drink, you’ll urinate about 16 ounces. Yikes! Honestly, a beer the night before a race probably won’t hurt, but beer as your energy prep plan, well, that leads to dehydration, less race-time energy, and decreased performance. Plus, there’s little reason to carbo-load for races under 90 minutes, anyway, but that’s for another Q&A.

This article originally appeared on Podiumrunner.com.