Featured Research

from universities, journals, and other organizations

Less exercise, not more calories, responsible for expanding waistlines

Date:
July 7, 2014
Source:
Elsevier
Summary:
Sedentary lifestyle and not caloric intake may be to blame for increased obesity in the US, according to a new analysis. A study reveals that in the past 20 years there has been a sharp decrease in physical exercise and an increase in average body mass index (BMI), while caloric intake has remained steady. Investigators theorized that a nationwide drop in leisure-time physical activity, especially among young women, may be responsible for the upward trend in obesity rates.

This graph shows the percentage of people who report no leisure-time physical activity, based on data from the 1988-94 vs. 2009-2010 NHANES.
Credit: The American Journal of Medicine, Ladabaum et al.

Sedentary lifestyle and not caloric intake may be to blame for increased obesity in the US, according to a new analysis of data from the National Health and Nutrition Examination Survey (NHANES). A study published in The American Journal of Medicine reveals that in the past 20 years there has been a sharp decrease in physical exercise and an increase in average body mass index (BMI), while caloric intake has remained steady. Investigators theorized that a nationwide drop in leisure-time physical activity, especially among young women, may be responsible for the upward trend in obesity rates.

Related Articles


By analyzing NHANES data from the last 20 years, researchers from Stanford University discovered that the number of US adult women who reported no physical activity jumped from 19.1% in 1994 to 51.7% in 2010. For men, the number increased from 11.4% in 1994 to 43.5% in 2010. During the period, average BMI has increased across the board, with the most dramatic rise found among young women ages 18-39.

"These changes have occurred in the context of substantial increases in the proportion of adults reporting no leisure-time physical activity, but in the absence of any significant population-level changes in average daily caloric intake," explains lead investigator Uri Ladabaum, MD, MS, Associate Professor of Medicine (Gastroenterology and Hepatology), Stanford University School of Medicine. "At the population level, we found a significant association between the level of leisure-time physical activity, but not daily caloric intake, and the increases in both BMI and waist circumference."

The study looked at the escalation of obesity in terms of both exercise and caloric intake. While investigators did not examine what types of foods were consumed, they did observe that total daily calorie, fat, carbohydrate, and protein consumption have not changed significantly over the last 20 years, yet the obesity rate among Americans is continuing to rise.

Researchers also tracked the rise in abdominal obesity, which is an independent indicator of mortality even among people with normal BMIs. Abdominal obesity is defined by waist circumference of 88 cm (34.65 in) or greater for women and 102 cm (40.16 in) or greater for men. Data showed that average waist circumference increased by 0.37% per year for women and 0.27% per year for men. Just like the rise in average BMIs, the group most affected by increased rates of abdominal obesity was women.

"The prevalence of abdominal obesity has increased among normal-weight women and overweight women and men," observes Dr. Ladabaum. "It remains controversial whether overweight alone increases mortality risk, but the trends in abdominal obesity among the overweight are concerning in light of the risks associated with increased waist circumference independent of BMI."

When Ladabaum et al grouped respondents to the most recent NHANES survey by race/ethnicity and age, they found that more than 50% of the workforce-aged adults in eight demographic subgroups reported no leisure-time physical activity. The following chart displays the results and highlights the differences between the 1994 survey results and those collected in 2010 (albeit, with slightly different survey methods). According to this data, women, and black and Mexican-American women in particular, showed the greatest decreases in reported exercise.

While increased caloric intake is often blamed for rising rates of obesity, no association between these was found in this study; in contrast, an association was found between the trends over time for lack of physical activity and high BMI numbers. "Our findings do not support the popular notion that the increase of obesity in the United States can be attributed primarily to sustained increase over time in the average daily caloric intake of Americans," concludes Dr. Ladabaum. "Although the overall trends in obesity in the United States are well appreciated and obesity prevalence may be stabilizing, our analyses highlight troublesome trends in younger adults, in women, and in abdominal obesity prevalence, as well as persistent racial/ethnic disparities."

There is no easy answer in our ongoing battle against obesity, but identifying the link between the drop in physical activity and increased BMIs, as well as the groups particularly affected, can assist public health officials to develop targeted, effective interventions. In an accompanying commentary Pamela Powers Hannley, MPH, Managing Editor, The American Journal of Medicine,notes, "If we as a country truly want to take control of our health and our health care costs, the Ladabaum et al paper should be our clarion call. From encouraging communities to provide safe places for physical activity to ensuring ample supply of healthy food to empowering Americans to take control of their health, we must launch a concerted comprehensive effort to control obesity."


Story Source:

The above story is based on materials provided by Elsevier. Note: Materials may be edited for content and length.


Journal References:

  1. Pamela Powers Hannley. Move More, Eat Less:It’s Time for Americans to Get Serious about Exercise. The American Journal of Medicine, 2014; DOI: 10.1016/j.amjmed.2014.05.026
  2. Uri Ladabaum, Ajitha Mannalithara, Parvathi A. Myer, Gurkirpal Singh. Obesity, Abdominal Obesity, Physical Activity, and Caloric Intake in U.S. Adults: 1988-2010. The American Journal of Medicine, 2014; DOI: 10.1016/j.amjmed.2014.02.026

Cite This Page:

Elsevier. "Less exercise, not more calories, responsible for expanding waistlines." ScienceDaily. ScienceDaily, 7 July 2014. <www.sciencedaily.com/releases/2014/07/140707134243.htm>.
Elsevier. (2014, July 7). Less exercise, not more calories, responsible for expanding waistlines. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/07/140707134243.htm
Elsevier. "Less exercise, not more calories, responsible for expanding waistlines." ScienceDaily. www.sciencedaily.com/releases/2014/07/140707134243.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Nurse Nina Pham Cured of Ebola

Texas Nurse Nina Pham Cured of Ebola

AFP (Oct. 25, 2014) — An American nurse who contracted Ebola while caring for a Liberian patient in Texas has been declared free of the virus and will leave the hospital. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) — IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) — A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) — The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins