A study that followed 15,765 adults for several years after asking them about their daily food and drink intake calculates that the effect of substituting a beer or sugar-sweetened soda with a glass of water relates to a lower incidence of obesity. Also, in the case of beer, such a substitution is linked to modest weight loss over a 4-year period.
However, the researchers - including members from the University of Navarra in Pamplona and the Carlos III Institute of Health in Madrid, both in Spain - say that these findings, which they arrived at using mathematical models, need to be confirmed using intervention studies that follow people who have actually been asked to replace one such drink per day with a glass of water.
A presentation about the study - which has already been published in the journal Nutrients - features at this year's European Congress on Obesity, held in Porto, Portugal.
Once a disease normally associated with wealthy countries, obesity is now becoming more common in low- and middle-income nations.
In the United States, health statistics show that more than one third (36 percent) of adults are obese, with men and women equally affected.
Being overweight or obese raises a person's risk of developing high blood pressure, heart disease, type 2 diabetes, and a range of other diseases, including some types of cancer, osteoarthritis, and nonalcoholic fatty liver disease.
The study examined the effect of 17 different beverages
In their study paper, the team explain how energy imbalance is the main cause of obesity, with sedentary lifestyle, epigenetics (such as the effect of lifestyle factors on gene expression), and over-consumption of calories playing major parts.
High intakes of beverages such as alcoholic and sugar-sweetened drinks are considered major contributors to weight gain, and the authors also note that people are less likely to feel full from consuming liquid calories as opposed to solid calories.
The objective of their study, therefore, was to calculate the effect that replacing one serving of beverage per day with a glass of water might have on the risk of developing obesity.
They chose to use data from the University of Navarra Follow-Up (Seguimiento Universidad de Navarra, or SUN) project, which is designed to explore the links between diet and chronic diseases such as obesity. SUN started recruiting participants in 1999, enrolling students attending the university.
The team followed a group of 15,765 adults who did not have obesity when they enrolled. The participants filled in questionnaires about their food and drink intake at baseline, and they then gave information about their obesity status every 2 years afterward.
The scope of the data allowed the researchers to assess the links between baseline consumption of 17 different beverages and the later onset of obesity over an average follow-up period of 8.5 years.
The 17 different beverages included: beer, spirits, sugar-sweetened soda, diet soda, coffee (regular and decaffeinated), milk (whole, reduced-fat, and skim), milkshake, wine (red and other kinds), fresh fruit juice (orange and non-orange), bottled juice (of any fruit), and water (tap and bottled).
Replacing one beer tied to 20 percent lower obesity risk
Of all the participants, 873 (6 percent) developed obesity during the follow-up period.
Using mathematical models, the researchers calculated that the effect of replacing a beer every day with a glass of water was linked to a 20 percent reduction in the risk of obesity. If the glass of water replaced a sugar-sweetened soda, the reduction in obesity risk was 15 percent.
There was no such link to obesity when the researchers looked at the effect of replacing any of the other 15 drinks with water.
The results were not affected by other potentially influencing factors, such as: sex, age, family history, physical activity, weight change in the past 5 years, snacking between meals, and total calories from drinks other than the two examined in each case.
The researchers also found a link between substituting water for beer and modest weight loss: over a period of 4 years, this was linked to a reduction in average weight of 0.3 kilograms (0.7 pounds).
The authors say that their findings suggest "that replacing one sugar-sweetened soda beverage (but not other sugared drinks like fruit juices) or beer with one serving of water per day at the start of the study was related to a lower incidence of obesity and to a higher weight loss over a 4-year period in the case of beer."
The authors note that the study may be subject to the usual limitations that studies using self-reported data are susceptible to.
They also point out that, as is common practice in population studies of nutrition, they used statistics to model a beverage substitution effect, and "thus real replacements may not show the same results." Therefore, in reference to this, they conclude:
"Nevertheless, longitudinal investigations based on real interventions are needed to confirm these potential effects. As obesity carries a high risk for the development of other diseases like diabetes or cardiovascular disease, the possible effects of the substitution for these beverages with water is an important target to consider in future public health research."