As some of you probably know, Mexico is one of the countries with the highest prevalence of obesity in the world. Depending on the information source, it is often ranked as second after the United States. In addition, Mexicans are the second greatest consumers of soft drinks in the world. Currently, there is some ecological evidence that associates the trends in soft-drink consumption and overall diet with the increase in the prevalence of obesity.
Body Mass Index Distribution in Mexican Women 18 to 49 Years Old (1988, 1999, 2006)
We have observed that the distribution curve of body mass index (BMI) for women (18-49 years) has shifted to the right, reflecting an increase in obesity and overweight. In the National Nutrition Survey of 1988, most of the population was less than 25 kg/m2 units, or what is considered to be a normal weight, and only 9.5% were obese (BMI, ≥30 kg/m2). Eleven years later (1999), we conducted a second nutrition survey and found that 24.9% of Mexican women were obese. In 2006, most of the population (32.4%) was either overweight or obese. These shifts are unprecedented (Figure 1; Rivera JA, González-Cassío T, Monterrubio E, personal communication, 2007). At the baseline in 1988, Mexican women had BMI prevalences similar to those in Brazil, but Brazil has not observed the same increase in the prevalence of obesity during the past 2 decades. Unique changes had occurred in Mexican society. In fact, the aggregated overweight and obesity prevalence rose from 34 (1988) to 61 (1999) to almost 70% (2006) between 1988 and 2006.
School-aged children and adolescents, similar to women, experienced significant increases in the prevalence of overweight and obesity. We have explored this trend at an ecological level, using diverse health, nutrition, and economic surveys to analyze factors that could be related to these changes in obesity within Mexican society. However, the evidence relating dietary and physical activity factors to obesity is not complete.
Changes in Food Purchases Between 1984 and 1998
In 2002, we documented an important decrease in fruit and vegetable consumption (ie, 29% between 1984 and 1998) and a stark increase in the consumption of soft drinks (almost 40%).1 This was one of the first pieces of evidence, based on income and expenditure surveys that we had of the huge increase in soft-drink and caloric beverage consumption. The subsequent studies conducted by our group and by other researchers in Mexico are consistent with these results, identifying very important changes in food and beverage patterns in this relatively small period.
Contribution of Beverages to Total Energy Intake of Mexican Women (1999)
For many years, perhaps even before our country became Mexico as we know it today, our citizens experienced diverse stages of famine and undernutrition. Caloric beverages were commonly used as a remedy to treat diarrheas (ie, juices, sweetened coffee, chocolate and tea, sweetened infusions); in recent years, the consumption of caloric beverages has continued to increase. When we analyzed the contribution of these beverages to the energy intake of Mexican women in 1999, they amounted to about 19% of the total energy in the diet.
Beverage Consumption Trends in Mexico (1999 and 2006)
Using the National Nutrition Survey for 1999 and 2006 to evaluate the trends among children and adolescents (10-18 years) and adults (19-49 years), we observed an increase in the energy coming from beverages from 645 to 1461 kJ for children and adolescents (a 226% increase) and from 607 to 1532 kJ (252%) in adults.2 Basically, most of this energy originated from high-sugar beverages.
The 2006 survey results identified a very important contribution from soft drinks starting at 12 years of age, but many other caloric beverages also contributed significantly. For example, whole milk was the most important caloric beverage in the 12- to 18-year age group and in adults 40 years or older. Among adults, we identified high consumption of coffee and tea with sugar, especially in rural and low-socioeconomic areas. The consumption of alcoholic beverages also was an important energy contributor, even among 12- to 18-year-old adolescents (280 kJ per capita); this concerned us for reasons of present health and future morbidity. Juices and sugar-sweetened beverages-not only soft drinks-contribute much to this consumption. To summarize, caloric beverages in Mexico include a combination of traditional and newer beverages. There are soft drinks, juice and water with sugar added, coffee or herbal infusions, fruit juices, and milk. About 22% of adult energy intake comes from caloric beverages (Figure 2).
We also analyzed the dietary habits of children aged 1 to 4 years and 5 to 11 years, between the years 1999 and 2006. A similar increasing trend for the energy content of beverages was observed (approximately 180% in both cases). However, in children, the main beverage contributing to total energy was whole milk.
Forming an Expert Panel
Following concerns about the increasing rates of obesity and chronic diseases, the Mexican Ministry of Health established an expert panel in 2008 for the development of recommendations on beverage intake for a healthy life, replicating a similar effort previously implemented in the United States. This experience provides an example of action that governments can take to reverse negative dietary trends that increasingly are becoming a public health concern.3
This committee conducted an extensive review of the published evidence on caloric beverages and health. In addition, it reviewed the patterns of beverage consumption in Mexico, using the 2006 Mexican Health and Nutrition Survey and other databases.
The expert group was formed by the Ministry of Health which with permission decided to adapt the recommendations about beverages for a healthy lifestyle that were published in the American Journal of Clinical Nutrition. Furthermore, the initiative received support from 2 distinguished US researchers-Prof Barry Popkin from University of North Carolina and Prof Walter Willett from Harvard School of Public Health, who were members of the US expert group.
Evidence About the Contribution of Caloric Beverages to Weight Gain
The evidence relating the contribution of caloric beverages to weight gain is growing each year. These studies, reviewed in detail by the expert panel, included (a) a 2006 systematic review that found evidence that a greater consumption of calorically sweetened drinks is associated with weight gain and obesity and (b) a recent meta-analysis that demonstrated clear associations between an increase of energy intake and an increase of obesity, type 2 diabetes mellitus, and other chronic diseases.
This expert panel took the following approaches during their deliberations:
- reviewed hunger and satiety as they relate to liquids and concluded that liquids are less satiating than solid foods and that beverages elicit poor dietary compensation. In other words, energy in fluids is not as readily "registered" in the brain for appetite compensation as solid foods are.
- evaluated the beverages consumed in Mexico, in terms of energy density, their contribution to total daily energy intake, and their beneficial or adverse health effects.
- organized all beverages into 6 categories: level 1, potable water; level 2, low-fat milk; level 3, coffee and tea/infusions with no sugar; level 4, noncaloric beverages with artificial sweeteners; level 5, caloric beverages with few health benefits (eg, fruit juices, whole milk, alcoholic beverages, sport drinks); and level 6, calorically sweetened beverages with low or no nutrient contribution. For each level, the expert panel identified the characteristics and evidence related to long-term health. Basically, the main conclusion of this panel was that water is the best option and first recommendation of beverages.
The panel recommended consumption of "…water or beverages without or with low energy density, and skimmed milk, over the consumption of high-energy beverages and sweetened beverages, even if artificial sweeteners are used."
To educate the public, the panel translated their recommendations graphically into a "healthy beverage pitcher," which could be coupled with the "healthy eating plate" (the Mexican equivalent of the US food pyramid). As illustrated in Figure 3, this panel recommended 6 to 8 glasses of water, 0 to 2 glasses of level 1 beverages, and 0 to 4 glasses of coffee or tea without sugar. In these recommendations, soft drinks and other beverages with added sugar are not recommended regularly (Figure 3).
Beverage Consumption (Energy Intake) Recommended for a Man to Achieve a Goal of Less Than 10% of Energy From Beverages
For a male to achieve the recommended beverage proportions, he should try to drink no more than 967 kJ in the form of beverages, for example, one-half glass of beer, or one glass of red wine; 2 glasses of fresh fruit drink with 5 g of sugar per glass; 2 cups of coffee or tea with no added sugar; one-half glass of natural juice and fruit drink with no added sugar; or one-half cup of low-fat milk. This allows for less than 10% of all energy to come from beverages, which is less than half of what is currently consumed by the Mexican population. To achieve the recommended beverage proportions, women in Mexico should consume 1 glass of fruit drink, 2 cups of coffee or tea with no sugar added, one-half glass of juice with no added sugar, and 1 cup of low-fat milk.
This experience provides health policy lessons that have great value for future projects with similar goals. First, the expert panel was named by the Ministry of Health based on scientific merit: all of the participants were well-known national investigators. Second, 2 internationally renowned researchers were invited to support the panel. Third, the characterization of beverage consumption was based on a representative survey of approximately 40 000 households and published in the Journal of Nutrition (2008). Fourth, the expert panel published their conclusions in the most widely read public health journal in Mexico (Salud Pública de Mexico), with reprints in the national journals of cardiology, pediatrics, and nutrition, among others. Fifth, the analysis was presented at scientific meetings such as the Experimental Biology annual meeting in the United States, with a very good response from the scientific community. Sixth, the article entitled, "Consumption of Beverages for Healthy Life in the Mexican Population," received much attention, in particular from healthcare professionals and the soft drink and milk industries. The editorial that preceded this article was written by the Mexican Minister of Health, who underlined the importance of drinking water and trying to promote the consumption of water at the school level, at the workplace, and so on. Seventh, the "healthy beverage pitcher" (see above) was promoted via posters and publications for all health sectors. In general, the support was unprecedented in the Mexican health community and included endorsement of the "healthy beverage pitcher" by the Inter-American Heart Foundation, the Society of Endocrinologists and Nutritionists, the Mexican Diabetes Federation, the College of Internal Medicine, the Mexican Association of Cardiologists, and the Academy for the Study of Obesity in Mexico. This support and endorsement from the most influential medical societies in turn helped to create a strong support among physicians and health professionals. The Ministry of Education has included this image in thousands of free primary school textbooks.
Although special interest groups voiced opposition (such as some milk producer associations), consumer groups in Mexico welcomed and supported this initiative through their communications networks. They also conducted supporting media activities. We expect that, in the future, the aforementioned efforts will stimulate consumer demand for healthier beverage products from industry, facilitating the regulatory and educational work of the government. In conclusion, much positive feedback has been generated, and the Minister of Health in Mexico has expressed his commitment to maintaining and supporting these recommendations.
A Model of Evidence-Based Policy Formation
The Mexican national beverage guidelines exemplify a process that involved characterizing dietary (ie, especially beverage) habits, forming an expert panel, translating recommendations into policies, and converting evidence into local programs. Thanks to this work, important modifications are already taking place. These include the reduction of fat in the milk which is distributed by the Mexican government as part of social programs for vulnerable and low-socioeconomic populations.
Mexico is facing a burgeoning epidemic of obesity and diabetes, coronary heart disease, and cardiovascular disease. We believe that, in part, the evidence indicates this epidemic is related to changes in the amount and type of beverages that are consumed. We also think that decreasing caloric beverage consumption is an essential part of the solution. The priority programs of the Ministry of Health and Education will include attempts to increase the consumption of water in schools and to improve the quality of the food available to students.
The development of evidence-based recommendations is required for evidence-based policy, but this is not enough. The complexities of governmental agencies require numerous key participants. For example, we have been collaborating with the Ministries of Education, Agriculture, Social Development, and Economics to organize unified messages to citizens and unified approaches to industry. Also, to maximize the benefits of small budgets for education and health, we hope to help children and adults make better choices in their diet.
This process was not clear to many key players in Mexico. For example, some leaders in the nutrition area felt excluded. We learned that a series of small group meetings, to present the expert panel recommendations, were valuable in building the consensus and support that was required to institute governmental policies.
Finally, despite declarations about commitment to health, the strong opposition from some industrial segments (such as industrialized food and milk associations) confirms that commercial interests sometimes prevail over health concerns, at both international and local levels. However, we are optimistic that the Mexican experience and future global trends will be strong incentives for industries and governmental officials to encourage healthier behaviors and products, without delay.