Two Duke Global Health Institute faculty members have articles in the November issue of Health Affairs, which is devoted entirely to the subject of food and health, marking the first time the publication has covered the subject in this way.
Eric Finkelstein and colleagues look at the connection between the consumption of specific food and beverages and weight gain among children and adolescents. Mary Story and colleagues examine the complex relationship between food and health, and provide policy recommendations designed to help people to eat better.
Finkelstein's team looked at a set of data from the Avon Longitudinal Study of Parents and Children in the United Kingdom which showed the level of consumption of 27 foods and beverages by a group of 4,646 young people age 7-13, in addition to their physical activity and weight. Children completed a food diary and had their height and weight measured at ages 7, 10 and 13. Their activity levels were measured with a device that calculates the duration and intensity of physical activity.
"Potato chips are one of the most obesity-promoting foods for young people to consume," Finkelstein said. He and his co-authors found that other problematic foods included butter and margarine, breaded or coated chicken or fish, French fries, processed meats, refined grains such as white bread, desserts and sweets, and milk and soda.
The characteristics or cooking processes of certain foods appear responsible for some of the negative effects, the study found. For instance, liquid calories have been shown to be more obesity-promoting than calories from solid foods, perhaps because beverages are typically less satiating than food. Despite the fact that both potato chips and French fries are on the "bad" list, potatoes themselves, when boiled or mashed without using oil, are highly satiating and contain a number of essential nutrients. Similarly, uncoated chicken and fish are not associated with weight gain.
At least 30 minutes of physical activity each day was associated with healthy weight levels.
"Our findings support policies that aim to reduce the intake of specific food items and efforts to change methods of cooking and processing food," Finkelstein said.
He also said the findings study support policy efforts underway in several countries around healthier school meals, limiting sales of super-sized sugar-sweetened beverages, and school- or community-based physical activity opportunities.
Connection between food and health and how policies can lead to healthy choices
Story and colleagues present a broad overview of the connection between food and health and suggest policies that alter the environment to promote healthy eating.
According to Story, the quality of the American diet has improved slightly over the decade 1999-2010, but it is still poor. The data her team examined showed that higher educational levels contribute to better dietary quality. The data also showed that children and young people don't eat enough healthy foods such as fruits, vegetables and whole grains, but load up on added sugars, sodium and saturated fats.
Alongside these worrisome trends are increases in obesity, diabetes, hypertension and food allergies. The data exposed significant disparities between whites and populations of color in disease prevalence.
How individuals choose, procure and eat food is governed by a complex set of variables, according to Story. Those variables include macro systems like agricultural policy and food manufacturing and social and cultural norms, and local factors like food availability in a particular neighborhood, family financial resources and personal taste.
In 2009, more than 19,000 new food and beverage products were introduced in the U.S., many of which resulted from advances in food science and food processing. "Unfortunately, many of those new products are high in calories and contain unhealthy fats and sweeteners," said Story. "But because they're cheap, tasty, and easy to prepare, they continue to make up more and more of the American diet."
Story and colleagues seek to attack the obesity epidemic with policy recommendations that mirror the influences that contribute to it. Starting at the macro level, they recommend labeling trans fats on packaged goods and posting of calories in chain restaurants. "Evidence suggests that these requirements have resulted in modifications to products to make them healthier," said Story.
They recommend changes in food marketing to young people, so that kids under 12 are exposed to healthy diet and lifestyle options. So far, as part of the Children's Food and Beverage Advertising Initiative, 17 companies have voluntarily agreed to abide by this recommendation.
According to Story, changes to federal programs that are implemented locally (such WIC, SNAP and school lunches) can make healthy food and beverage options more widely available, resulting in individuals and families making healthier choices.
At the individual level, increasing taxes on items such as sugary beverages has been shown to work. Providing additional money to SNAP users when they purchase fresh produce reduces this well-documented price barrier.
"There is no magic bullet when it comes to addressing broad cultural, societal and biological factors that contribute to the obesity epidemic," said Story. "It will take a broad, comprehensive commitment at many levels to tackle the formidable environmental factors that contribute to unhealthy eating."