It's a common assumption. We see a guy with a bit of a gut, and we just automatically think...he must like his beer. The idea of the beer gut is strong in Western culture. People talk about trying to lose it. Hipsters talk about trying to gain it. That chick from Pulp Fiction thinks they're sexy.
But here's the question: is a beer belly a beer BELLY? Does all the beer indeed go straight to your gut? Or does it also go elsewhere? Where do we find the answers to these burning life questions: the cure for cancer, the origins of life, the why of the beer belly?
For this, we need SCIENCE.
(Source. And some beer. Science goes best with beer.)
Schutze et al. (appropriately enough, this study is from Germany) "Beer consumption and the ‘beer belly’: scientific basis or common belief?" European Journal of Nutrition, 2009.
There is actually a medically sound reason to do this study. Carrying most of your weight around your midsection (measured as waist circumference) is a risk factor for things like cardiovascular disease. So knowing the potential causes behind abdominal obesity could help target behaviors that might result in specific increases in waist circumference.
And why was this done in Germany? Well, Germans drink a lot of beer. 1121 beers per year per capita (according to this paper, anyway). Popular national beverage. And Germany also has a large pile of data from the European Prospective Investigation into Cancer and Nutrition. Using that data, the authors of this study looks at rates of beer drinking and changes in waist circumference over a four year period. They compared it to changes in hip circumference to control for total weight gain. And divided the groups up into 4 categories for women:
1) No beer
2) very light drinkers: up to 125 mL/day
3) light: between 125 and 250 mL/day (keep in mind this is average, people aren't really drinking quarter liters of beer at a time)
4) moderate: more than 250 mL/day
with no women averaging higher than that (remember, this does not include other types of alcohol, so they could conceivably make up the difference in other areas).
The men got 5 categories:
1) no beer
2) very light: less than 250 mL/day
3) light: between 250 and 500 mL/day
4) moderate: between 500 mL/day and 1000 mL/day
5) heavy: more than 1 liter of beer per day.
(the usual bottle size in Germany is 0.5L, so you have to average 2 bottles of beer per day for a year to make the heavy)
Above is the study design. You can see the four followup points, and that they also looked at INCREASES in beer consumption.
And what did they find? Well, overall, 2/3 of the women and the men gained weight. Women, however, did not show a linear correlation between beer consumption and waist circumference. In fast the waist circumference decreased in the moderate drinkers and increased in the light drinking. No evidence for the beer gut in women.
In men, the heaviest beer consumption was associated with a significant increase in waist circumference. Seems like a beer belly might be going somewhere. But when you added in (for both men and women) changes in hip circumference as well as waist circumference, all the changes disappeared. Drinking large amounts of beer is correlated with increase weight gain overall, not a beer belly. In other words: drinking beer does give you a gut. It also gives you a butt.
Of course, they didn't assess the effect of the beer INDEPENDENT of other factors. For example, what if people who drink a lot of beer eat more? What if they exercise less? How much of the gut is the beer REALLY accounting for here?
But the moral of this tale is in a poem:
All ye who love beer
the beer belly don't fear!
The belly will bulge as you sip
But it'll balance out with beer hip.
Schütze M, Schulz M, Steffen A, Bergmann MM, Kroke A, Lissner L, & Boeing H (2009). Beer consumption and the 'beer belly': scientific basis or common belief? European journal of clinical nutrition, 63 (9), 1143-9 PMID: 19550430