Alcohol and Body Fat

According to conventional wisdom, the infamous “beer belly” is caused by excess alcohol calories being stored as fat.

However, researchers from the University of California have shown that less than 5% of the alcohol calories you drink are turned into fat. Rather, the main effect of alcohol is the way it reduces the amount of fat your body burns for energy. Successful weight loss is all about oxidizing (or burning), more calories than you eat. When dieting many people choose low-calorie alcoholic drinks, mainly because they contain fewer alcohol calories than their regular counterparts.

However, this recent study, published in the American Journal of Clinical Nutrition, shows that even a very small amount of alcohol has a large impact on fat metabolism. Eight men were given two drinks of vodka and lemonade separated by 30 minutes. Each drink contained just under 90 calories. Fat metabolism was measured before and after consumption of the drink.
For several hours after drinking the vodka, whole body lipid oxidation (a measure of how much fat your body is burning) dropped by a massive 73%. Here’s why… Rather than getting stored as fat, the main fate of alcohol is conversion into a substance called acetate. In fact, blood levels of acetate after drinking the vodka were 2.5 times higher than normal and it appears this sharp rise in acetate puts the brakes on fat loss.

A car engine typically uses only one source of fuel. Your body, on the other hand, draws from a number of different energy sources, such as carbohydrate, fat, and protein. To a certain extent, the source of fuel your body uses is dictated by its availability. In other words, your body tends to use whatever you feed it. Consequently, when acetate levels rise, your body simply burns more acetate, and less fat. In essence, acetate pushes fat to the back of the queue.
So, to summarize and review, here’s what happens to fat metabolism after the odd drink or two…

1 A small portion of the alcohol is converted into fat.

2 Your liver then converts most of the alcohol into acetate.

3 The acetate is then released into your bloodstream, and replaces fat as a source of fuel

The body's response to alcohol is very similar to the way it deals with excess carbohydrate. Although carbohydrate can be converted directly into fat, one of the main effects of overfeeding with carbohydrate is that it simply replaces fat as a source of energy. That’s why any type of diet, whether it’s high-fat, high-protein, or high-carbohydrate, can lead to a gain in weight.

Siler, S.Q., Neese, R.A., & Hellerstein, M.K. (1999). De novo lipogenesis, lipid kinetics, and whole-body lipid balances in humans after acute alcohol consumption. American Journal of Clinical Nutrition, 70, 928-936