Obesity, Diet and Mortality Trends: There’s Work To Be Done

The current data on youth obesity in the U.S. illustrate that, while gains have been made in the fight for healthy children and adolescents, America’s weight problem endures and challenges remain. After all, it is not easy to reduce our national waistline while American restaurants continue to routinely and proudly offer more than a whole day's calories and six days’ worth of sodium in one sitting, as was recently highlighted in the Center for Science in the Public Interest's 2016 Xtreme Eating "Awards." But let’s start by looking at the present data.

Youth obesity facts
Previous analyses of obesity trends among children and adolescents showed an upward climb for roughly the decade between 1988 and 2000, but no change between 2011 and 2012, except for a significant decline among children aged two to five years.

But a detailed new analysis published in JAMA shows that:

  • From 2011 to 2014, 17% of children and adolescents (aged two to 19 years) were obese and 6% were extremely obese
  • Among children aged two to five years, obesity rates increased from 7% in 1988-1994 to 14% in 2003-2004, and then decreased to 9% in 2013-2014
  • Among children aged six to 11 years, obesity rates increased from 11% in 1988-1994 to 20% in 2007-2008 and generally remained stable thereafter
  • Among adolescents aged 12 to 19 years, obesity rates continued to increase from 10% in 1988-1994 to 21% in 2013-2014

This data, culled from the National Health and Nutrition Examination Surveys, illustrates that obesity continues to haunt children and adolescents despite the many attempts to intervene. Among children and adolescents aged two to 19 years, the prevalence of obesity in 2011-2014 was approaching one-fifth of that entire population.

Death by saturated fat is real
Much has been made recently of various findings that illuminate the complicated role of fat in the diet. Unfortunately, too much of that nuanced data has been exploited for clickbait in the media that tells people that bacon is just fine and the more cheese the better.

It is true that while previous studies have shown distinct associations between specific dietary fat and cardiovascular disease, evidence on specific dietary fat and mortality remains limited and inconsistent.

To clarify the matter, a recent study published in JAMA Internal Medicine examined the associations of specific dietary fats with total and cause-specific mortality in two large ongoing cohort studies.

After looking at diet and mortality for 30 years among 125,000 male and female health professionals free of cardiovascular disease, cancer and diabetes at baseline, the clear-cut findings were:

  • High intake of saturated fat replacing carbohydrates was associated with an 8% increase in total mortality. High trans fat intake led to a 13% mortality increase
  • High intake of polyunsaturated and monounsaturated fat was associated with 19% and 11% reductions in mortality, respectively
  • Replacing 5% of calories from saturated fat with calories from polyunsaturated and monounsaturated fat was associated with mortality reductions of 27% and 13%, respectively

As is therefore obvious, the authors write that replacement of saturated fats with unsaturated fats “should continue to be a key message in dietary recommendations. These findings also support the elimination of partially hydrogenated vegetable oils, the primary source of trans-fatty acids."

Adult dietary patterns: Eat by example
When researchers examined dietary trends, collected for over a decade among roughly 34,000 U.S. adults, they found that diets consisted generally of more whole grains, nuts and fruit, and fewer sugar-sweetened beverages. This is a promising development, though when analyzed in detail it’s safe to say the gains were modest and the scope limited to too few among the population at large.

The study aimed to characterize trends in overall diet quality as well as specific dietary components, as they are related to major diseases among U.S. adults, broken down by various demographics, including age, sex, race, education and income.

The general findings:

  • During the study period, there were significant increases in mean daily consumption of whole grains (by 0.43 servings)
  • Consumption of nuts, seeds and legumes  increased slightly (by 0.26 servings)
  • Whole fruit consumption barely increased (by 0.15 servings), but at least did not decrease
  • Mean daily consumption of 100% fruit juice and sugar-sweetened beverages decreased significantly (by 0.11 servings and 0.49 servings)
  • The proportion of diets rated as poor declined from 56% to 46%
  • Diet scores improved for all subgroups stratified by education and income, but the disparities present in earlier scores widened over time in favor of those with higher education and income levels

The authors write, “These findings may inform discussions on emerging successes, areas for greater attention, and corresponding opportunities to improve the diets of individuals living in the United States.” The take-home message is, the average U.S. diet has improved somewhat in recent years, but nearly half of adults still consume poor-quality diets.

Recall the new guidelines
To help keep you and your family on track, it’s worth reviewing the U.S. Departments of Agriculture and Health and Human Services 2015-2020 Dietary Guidelines for Americans. The recommendations include:

  • Choose a healthy eating pattern that you can stick to over the long term. Consider personal taste preferences, culture, and budget
  • Consume a wide range of nutrient-dense foods from all food groups in recommended amounts
  • Focus on vegetables (including dark green, red, orange), whole fruits, whole grains, fat-free or low-fat dairy products, seafood, lean meats, poultry, legumes, eggs, nuts, and oils
  • Limit added sugars to less than 10% of calories
  • Limit sodium  to less than 2,300 mg/day
  • Limit saturated fats to less than 10% of daily calories and avoid trans fats altogether
  • Replace less-healthy foods and beverages with nutrient-rich ones across all food groups. Start with small changes, such as switching from refined-grain to whole-grain bread

CSPU, Aug. 2016, Xtreme Eating Awards, https://cspinet.org/news/dave-busters-uno-among-2016-xtreme-eating-award-recipients-20160801

JAMA, 2016, Vol. 315, No. 21, pp. 2292-9

JAMA Int Med, 2016, Vol. 176, No. 8, pp. 1134-45

JAMA, 2016, Vol. 315, No. 23, pp. 2542-53, http://jama.jamanetwork.com/article.aspx?articleid=2529628

Dietary Guidelines for Americans 2015-2020, https://health.gov/dietaryguidelines/2015/guidelines/executive-summary/

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