Beer belly and genetics

Monday July 6 2009

Experts claim that “beer does not cause pot bellies”, The Sun reported. The newspaper said the researchers had found that heavy drinkers do put on weight, but it is spread all over their body. It said that the pot belly, long thought to be associated with drinking, may be due more to genetics.

This cohort study looked at beer consumption, weight and body measurements in almost 20,000 people on two occasions over an average of six years. It found that increased beer consumption over time was linked with increased waist circumference, particularly for men. However, once a person’s overall weight was taken into account, the significance of these associations disappeared. This suggests that any weight gain from beer is distributed all over the body, rather than being concentrated around the waist.

Although this study does not support the notion of a ‘beer belly’ as such, it demonstrates that the more beer you drink, the more weight you gain. Beer and other alcoholic drinks are high in calories and will contribute to weight gain if taken in excessive amounts, as well as being detrimental to health in numerous other ways.

Where did the story come from?

The research was carried out by M Schutze and colleagues from the German Institute of Human Nutrition Potsdam-Rehbrucke and Fulda University of Applied Sciences, Germany, and the University of Gothenburg, Sweden. The study was funded by German Cancer Aid, the German Federal Ministry of Education and Research, and the European Union. The study was published in the peer-reviewed medical journal European Journal of Clinical Nutrition .

What kind of scientific study was this?

This cohort study aimed to investigate gender-specific associations between beer consumption and waist circumference (WC), and to challenge the commonly held belief that a ‘beer belly’ is caused by drinking beer. Obesity that is centred around the abdomen is said to be one of the strongest cardiovascular risk factors.

This study used data from the European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam study. In total, the EPIC study involved 27,548 people between 35 and 65 years old who were recruited between 1994 and 1998. This analysis was based on 19,941 members of this cohort (62% of whom were female) who had information available on their beer consumption and waist circumference. Alcohol consumption over the past year was assessed at the beginning of the study using a food frequency questionnaire, and then reassessed at follow-up about six years later.

The researchers gave men and women different categories of beer consumption. For example, in women the highest category of consumption of 250ml/day or more was considered ‘moderate’, while in men 250 to 500ml/day was considered ‘light’; 500 to 1000ml/day ‘moderate’; and anything above this level was considered ‘heavy’. At the beginning of the study, body weight, hip and waist circumference were measured, with any change in these measurements assessed at follow-up. In their analyses, the researchers used statistical models to look at changes in waist circumference for each beer consumption category, while also taking into account concurrent changes in body weight and hip circumference in order to monitor the site-specific effect of beer. They also looked at how changes in beer consumption affected changes in waist circumference. Age, smoking, education, physical activity and several other chronic diseases were also taken into account by the researchers.

What were the results of the study?

The waist circumference of 41% of men and 32% of women remained stable overtime, while 57% of men and 67% of women increased their waist circumference. Stable beer consumption was observed in 57% of men and 69% of women, while consumption decreased in 30% of men and 22% of women.

At the beginning of the study, a positive link between beer consumption and waist circumference was seen in men but not in women. Overall, both waist circumference at the start of the study and at follow-up increased significantly when more beer was drunk, although separate analysis by gender found that this relationship was significant in men only.

Men with heavy beer consumption (1000 ml/day or more) had 17% significantly increased risk of waist circumference gain compared with very light consumers (less than 250ml/day). Women who abstained from beer had 12% significantly lowered risk of increasing their waist circumference compared with very light drinkers (less than 125ml/day).

The significance of these risk associations was removed after taking into account concurrent body weight and changes in hip circumference. This suggests that a change in beer consumption was affecting overall weight rather than just waist circumference. Reducing beer consumption was also related to, and increased the chance of loss, in waist circumference. However, this association was not statistically significant.

What interpretations did the researchers draw from these results?

The authors conclude that beer consumption leads to a gain in waist circumference, which is closely related to concurrent overall weight gain. This study does not support the common belief of an effect of beer specifically on the abdomen, i.e. the ‘beer belly’.

What does the NHS Knowledge Service make of this study?

This modelling study investigated beer consumption and weight and body measurements in almost 20,000 people after six years. Although an increase in beer consumption over time was linked with an increase in weight circumference, particularly for men, these associations became insignificant after taking into account the person’s overall weight. This suggests that any weight gain from beer is distributed across the body, rather than just centering on the waist. There are several points to think about when considering the implications of these findings:

  • Although this study does not support the notion of a ‘beer belly’ as such, it upholds the theory that increasing beer consumption makes you gain weight. Beer and other alcoholic drinks are high in calories and will contribute to weight gain if drunk in excessive amounts, as well as being detrimental to health in many other ways.
  • Beer consumption was assessed by food frequency questionnaire. These questionnaires are always subject to errors because they rely on people accurately recalling their consumption over a period of time, in this case, one year. In addition, consumption of some foods and drinks can change over time, and people may also quantify things differently. Only the volume of beer was taken into account, but not its strength. Additionally, body measurements were self-reported by the individuals, and therefore cannot be considered to be as accurate as measurements made objectively by the researchers.
  • Some categories of beer consumption contained only a small number of study participants. This increases the probability that any differences occurred by chance.
  • Beer was specifically investigated in this study. No assumption can be made about the effects of other alcoholic drinks, such as wine and spirits, because they have not been examined (although they were adjusted for in risk calculations for beer).
  • The headlines say that genetics are the cause of a ‘beer belly’, rather than alcohol. The role of genetics in body weight has not been investigated by this study at all.

The best way to keep weight down is by eating a healthy diet, exercising regularly, and keeping alcohol consumption at low to moderate levels.

Analysis by Bazian
Edited by NHS Choices