New York City's controversial plan to restrict the size of sodas sold by restaurants, movie theaters and other venues to 16 ounces sounds like sweet music to the ears of many health experts, who attribute the surging obesity rate in the U.S. to over-consumption of sugary beverages. Dr. Margarita Teran-Garcia, who is a pediatrician and a professor of food science and human nutrition in the College of Agricultural, Consumer and Environmental Sciences, has conducted research on the genetic and environmental factors that influence the development of childhood obesity. Teran-Garcia is an active member of the Obesity Society, an organization that promotes interdisciplinary research, education and advocacy related to obesity, which has expressed its support for the soda ban. She spoke with News Bureau reporter Sharita Forrest about the ban and efforts to address obesity.
What are your views on New York's soda ban? Does it make sense to regulate soft-drink consumption or are sodas just an easy scapegoat for a complex public health problem?
I really agree that we should limit the sizes of sodas. In the 1960s, sodas were about 6 ½-7 ounces. We now have easy access to 20- to 32-ounce bottles, and in some places, even larger containers.
When drinking a soda, we don't get the same level of satiety that we would achieve if we consumed sugar by itself, and it becomes a very serious problem. A 32-ounce bottle of soda may contain almost half a cup of sugar - or more than 25 sugar cubes - and 4 cups of water. If you just ate the sugar by itself or drank water alone, you wouldn't eat or drink that much. But when you drink a soda, you don't notice it. The brain just doesn't receive the satiety signal that tells you to stop.
Drinking excessive amounts of 100 percent fruit juice could also be a problem because of its high sugar content, but the difference is that those are natural sugars, and juice also provides some vitamins and minerals.
Soda provides all these empty calories that we consume in excess and we gain weight. More than half of the population of the U.S. - 66 percent - is overweight or obese as are half of Canadians and Mexicans.
Individual responsibility is affected by environmental factors. Some individuals are less responsive to environmental cues, but we need to facilitate people's making the right choices to achieve better health outcomes, and we have a responsibility to educate people about how to make them.
Some health experts have identified high fructose corn syrup, the sweetening agent in many sodas, as particularly egregious. Is it really that bad?
The criticism is justified in that some research provides evidence of a relationship between high consumption of sugar-sweetened beverages and excessive caloric intake. Certain people also might have trouble metabolizing the excess calories and develop metabolic diseases, including what is known as fatty liver disease or non-alcoholic hepatic esteatosis. There is epidemiological data that links the inclusion of high fructose syrup in soda and food and the parallel development of the current obesity epidemic.
A recent study that followed 91,000 women for eight years found that they were more likely to develop high blood pressure and diabetes if they drank one or more servings of soft drinks a day.
What is the impact of genetics on the development of obesity?
The evidence from family and twin studies indicates that 40 to 70 percent of susceptibility to obesity could be attributed to genetics. However, the environment - which includes access to fruits and vegetables, the amount of physical activity and the availability of resources for exercise - accounts for about 30 to 60 percent. Cultural practices may account for up to 10 percent of those environmental factors.
Genetics is the part that we really need to understand better and how it interacts with the environment to predispose people to developing the complications associated with obesity.
The traditional Latin American diet is rich in fruits and vegetables but the transition to a Westernized diet with its greater consumption of processed food has been associated with weight gain. Lack of access to fresh fruits and vegetables in areas called "food deserts" also promotes obesity development in many Latin American communities in the U.S.
I'm working on a multidisciplinary project with a major university in Mexico in which we're exploring how genes and environment interact to predispose some young adults ages 18-21 in Mexico to metabolic syndrome. We have data on their health status when they apply to college and blood samples to identify metabolic markers and genetics. They also complete a very comprehensive questionnaire that tells us about their nutrition, physical activity, family relationships, depression and other social-environmental elements that interact with their biology to put them at risk of developing chronic diseases related to obesity.
When we have the resources, we'd like to extend the study to Hispanics and Latinos in the U.S. to explore how changes in cultural practices affect obesity and chronic diseases.
Losing weight is a real struggle for many people, and many who lose weight, regain it. Do genetics stack the deck against us in battling the bulge?
Predisposition is not genetic determinism. Even if you have a genetic predisposition to store extra weight, diet and exercise can help overcome that. And you can delay the onset of diseases such as diabetes by many years through proper diet and exercise.
It is very difficult to lose and maintain weight as adults but many people do it - and it doesn't take that much exercise to achieve it. And it pays off in a better quality of life.
We need to implement more nutrition education and lifestyle changes as early as possible in children's lives to help the next generation be successful. When I was doing my pediatric residency, we didn't see children with Type 2 diabetes and high blood pressure as we commonly do now.
I am part of the STRONG Kids project, a three-year study that is looking at the trajectories of weight gain among 3- to 5-year-olds in child care environments and the genetic factors that influence the development of obesity and their interaction with the environment. (Attending child care has been identified as a risk in the development of childhood obesity.) We are using the Six C's model to identify the key determinants of childhood obesity at the cellular, child, clan, community, country and cultural levels.
Why is abdominal fat in particular considered a serious health threat?
Fat cells not only store fat, they secrete hormones - cytokines and adipokines. For example, the gene leptin is produced by fat cells once the body has stored enough fat and sends signals to the brain that control satiation and tell you to stop eating.
With excess fat, adipocytes become sick; the tissues around them become inflamed, and there's a spillover effect that sends fat for storage in the liver, the muscles and the heart, where fat stores can interfere with proper function. It also promotes insulin resistance, the first step toward diabetes and fatty liver disease. Over time, excessive fat accumulation predisposes you for heart attack and arteriosclerosis.
Abdominal obesity - fat surrounding the abdominal organs - has been the most strongly correlated with insulin resistance, increasing the risk for developing diabetes by two-fold, and of having cardiovascular disease by three-fold.