Why does alcohol make you fat?

We’re all aware of the infamous “beer belly” but why does alcohol make us fat?

Well, the answer to that question is two-fold:

Firstly, alcohol is highly calorific, containing 7kcal per gram and it can easily be over-consumed. Compared to other components in our diets, alcohol is more calorie-dense than both protein and carbohydrate. As an example:

  • Alcohol is 7kcal/g
  • Fat is 9kcal/g
  • Protein is ~4kcal/g
  • Carbohydrate is ~ 4kcal/g

Secondly, the presence of alcohol in your system has a negative impact on your ability to metabolise fat;

A study in the American Journal of Clinical Nutrition highlighted this; 8 men were given two drinks of vodka and sugar-free lemonade, 30 minutes apart. Each drink contained just under 90 calories.

Fat metabolism was measured before and after consumption of the drink. For several hours after the drinks, whole-body lipid oxidation (a measure of how much fat your body is burning) dropped by a huge 73%! Let’s just think about that, the body was 73% less efficient at burning fat after the consumption of the alcoholic drinks.

The reason why alcohol has such a dramatic effect on fat metabolism has to do with the way alcohol is handled in the body. Instead of being stored as fat, the main fate of alcohol is conversion into acetate. The presence of acetate in the system puts the brakes on fat loss. The greater the quantity of alcohol, the greater the quantity of acetate created and the less likely fat is metabolised.

Put simply, when alcohol is consumed, it is converted to acetate in the body. Unfortunately, when acetate levels rise, your body chooses to burn that over fat. Too much acetate in the system basically pushes fat oxidation out of the metabolic equation leading to an increase in fat.