For years, the increased rate of obesity in America has been attributed to eating too much and exercising too little – but little hard data ever backed that claim. Now it appears that eating too much is to blame. A new study, presented at the May 2009 European Congress on Obesity, has shown that America’s obesity epidemic can be solely linked to excesses in energy (calories).
Approximately 1,400 adults and 1,000 children were tested on how many calories their bodies burned under free-living conditions. Once scientists determined the subject’s calorie burning rate, they were able to calculate how many calories a person would require to maintain a stable weight over a period of time. The researchers then predicted, using equations, how much weight a person should expect to gain over a 30-year period if food intake was the only cause of that weight gain.
Using national food supply data, the researchers analyzed how much food the average American consumed in the 1970’s and in 2000. Using data from the nationally recognized National Health and Nutrition Examination Survey (NHANES), they tracked the recorded weight of Americans in 1970 and 2000 to determine the actual weight gain over that period.
In children, the predicted and actual weight increase matched exactly, indicating that increases in food intake alone could explain the weight increase over the past 30 years. In adults, researchers predicted a 10.8 kg (23.7 lbs) weight gain, but in actuality it was 8.6 kg (18.9 lbs). The lower-than-expected weight gain indicates that food intake was still in excess, but that there may have been increases in physical activity that prevented the higher predicted weight gain.
The researchers suggest that to return to the average body weight of the 1970’s, children would need to reduce their intake by 350 calories (approximately a small serving of French fries and a 12-ounce soda), and adults 500 calories per day (a Venti® Frappuccino® has 560 calories!). This could be achieved by lowering food intake alone or in combination with an increase in calorie-burning physical activity.
Nutrition Note: Although it is clear that most American’s should reduce their portion sizes and monitor their overall food intake, physical activity is still an important player in weight management and improved cardiovascular health.
Information gathered from the European Congress on Obesity press release dated May 8, 2009.
Written by Melissa Ohlson, MS, RD, LD, Preventive Cardiology and Rehabilitation.
Get more information on nutrition strategies. To make an appointment with a registered dietitian, call the Cleveland Clinic Preventive Cardiology - 216.444.9353 or 800.223.2273 ext. 9353. Or, get a nutrition consultation online with our private and secure MyConsult Nutrition Consultation.
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