Does drinking alcohol make you gain fat?

Short answer

A lot of it does. People who kept drinking 30 g of alcohol a day or more (about 830 mL of beer) gained the most. Small amounts made no difference to weight, but on drinking days fat burning dropped 73% and people took in about 256 kcal more.

Does drinking alcohol make you gain fat?
'Alcohol calories → belly fat' — does this formula hold?
A common belief: alcohol is 'empty calories,' so it turns straight into belly fat. Others say alcohol doesn't turn into fat at all. We checked how the body handles alcohol and whether people actually gained weight.
Alcohol itself has calories
1 g of alcohol is 7.1 kcal, second only to fat
1 g of alcohol has 7.1 kcal, more than carbs or protein (4 kcal) and a bit less than fat (9 kcal). The roughly 18 g of alcohol in a 500 mL beer (4.5%) alone is about 128 kcal.
While you drink, you burn less fat
Whole-body fat burning dropped 73%
After 8 people drank 24 g of alcohol (about 670 mL of beer), the fat burned by the whole body dropped 73%. Fat released from fat tissue dropped 53%. The body used fuel made from the alcohol first and put fat on hold.
So do you eat fewer snacks?
No, people ate more
An analysis that pooled 22 trials with 701 people found no study where people ate less food to make up for the alcohol calories. Combining 12 trials, calories from food rose by about 82 kcal, and total calories including the drinks were about 256 kcal higher.
But over the long run
Drinking by itself made no difference
An analysis of 127 studies looked at the ones that followed people over time: drinkers had no higher risk of gaining a lot of weight than non-drinkers. A UK study that re-measured 45,399 people also found no meaningful difference in weight or waist size by how much they drank.
The amount was what mattered
People drinking over 30 g a day gained the most
A UK study followed 7,608 people for 5 years. Those who kept drinking 30 g or more of alcohol a day, or started drinking that much, gained the most weight. Heavy drinkers who cut back gained less. An analysis of beer studies also linked more than 500 mL a day to belly fat.
Small amounts made no difference over 2 years
A glass of wine at dinner: same weight, same belly fat
48 people with diabetes on a Mediterranean diet drank 150 mL of red wine or water with dinner every night for 2 years. Weight fell 1.3 kg with wine and 1.0 kg with water, with no difference, and visceral (deep belly) fat measured by MRI changed no differently.
Bottom line: alcohol becomes fat when you drink a lot
The tipping point: 30 g a day, about 830 mL of beer
Drinking pauses fat burning and makes people eat more, but people who drank small amounts did not gain weight over years. Those who gained the most kept drinking 30 g or more a day (about 830 mL of beer). If you're dieting, watching both the snacks and the amount on drinking days is enough.