April 7, 2015

We’re Eating Smarter and Still Getting Fatter. Solution? More Exercise!

If there’s a theme that runs through this blog, it’s this: as far as achieving and maintaining good health is concerned, there is no substitute for exercising regularly and eating wisely. Although countless millions of us might wish otherwise, there is no easy pill fix available that can replace the benefit of making the smart -- often challenging -- lifestyle choices.

A new report published in the April 2015 edition of the journal Medicine & Science in Sports & Exercise suggests we might need to list those two key lifestyle elements in a different order -- (1) exercise, and (2) diet.

We already know how much easier it is to pack on the pounds as we age. Waist measurements increase, and body mass index (BMI) gets higher and higher. Nearly 70% of Americans – of all ages -- are either obese or overweight. That percentage is higher among seniors.

We also know that being overweight carries risks, including diabetes, hypertension, cardiovascular disease, and certain cancers.

This new study analyzed physical activity, diet and weight among nearly 5,000 American adults from age 20 to 70 and above. The data provide an intriguing snapshot of how Americans are aging, and how their diet and exercise change through the years.

There’s lots of information in the report, but there's a paradox that's especially interesting -- while we age and gain those extra pounds, our diets are actually improving. We’re eating smarter and still getting fatter.

MVPA, the Key Element
What’s missing is EXERCISE. In particular, moderate-to-vigorous physical activity (MVPA).

Lead researcher Dr. Russell Pate at the University of South Carolina put it this way:
Our study points to the very important impact of physical activity on weight status in U.S. adults, and in particular it points to the critical role of the age-related decline in physical activity on the increasing rates of overweight and obesity that we see with aging. Our findings indicate that increasing fatness with age in U.S. adults cannot be explained by changes in the quality of the diet they consume.

Pate and his team used data from the Centers for Disease Control’s National Health and Nutrition Examination Survey (NHANES) from 2003–2004 and 2005–2006. All study participants were interviewed in their homes and given health examinations.

Their activity was tracked by accelerometer, and key stats collected, including weight, waist circumference, and diet quality. The researchers assembled information for men and women 20-29, 30-39, etc. Pate’s team then controlled for factors like race, ethnicity, socioeconomic status and smoking history.

Results and Conclusions 
The study extract includes these results:
  • Across age groups, MVPA (moderate to vigorous physical activity) was lower in the older age groups for both men and women, whereas diet quality was higher.
  • Predictably, BMI and waist circumference were also higher in the older age groups.
  • Within age groups, MVPA was inversely associated with BMI and waist circumference for men and women in nearly every age group. No surprise there -- the less exercise, the bigger the belly.
  • Diet quality was inversely associated with the weight status variables (i.e., better diet = less weight) only in men age 30–39, 40–49 (BMI only), and 50–59, and in women age 50–59. In the other groups, higher diet quality correlated with increased weight.

 The study abstract includes these conclusions;
  • There are clear age-related trends for measures of weight status, physical activity, and diet quality in American men and women.
  • MVPA was very consistently related to weight status in both genders. The relation between diet quality and weight status was less consistent.
  • These findings provide support for public health efforts to prevent obesity by promoting increased physical activity in adult Americans.

 Here's how researcher Tate summed it up:

Americans should meet the federal physical activity guideline, 150 minutes of moderate intensity physical activity per week. If most American adults met that guideline rates of overweight and obesity would be substantially lower than they are today.

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