The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Maybe we aren't eating more!

Posted in
Live well

Friday, Jan 14, 2011

How many calories do you think the average American consumes each day? And what percentage of calories does he/she consume from carbohydrates, proteins, and fats? Do you think either of these have changed over the past 10 years?

A report recently released from the Centers for Disease Control and Prevention's National Center for Health Statistics answers just these questions1. Using data from the National Health and Nutrition Examination Study (NHANES), an ongoing study designed to monitor the health and nutritional status of the civilian, noninstitutionalized U.S. population, this report compares intake of energy (calories) and macronutrients (carbohydrates, proteins, fat) in adults from 1999-2000 through 2007-2008. 

Before reading this report my guess was that American men and women consume way more calories than their bodies need; consume too many calories from carbohydrates (added sugars) and fats (unhealthy fats); and that over the past 10 years the average calorie intake by Americans has increased significantly.

Boy was I wrong! Here are some of the key findings from this report:

  • In 2007-2008 (the most recent data) the average energy (calorie) intake for men was 2,504 calories and for women it was 1,771 calories. [Note: use the MyPyramid Plan to find out what's recommended for you]
  • The average carbohydrate intake was 47.9% of total calories for men and 50.5% of total calories for women. [Note: 45-65% is recommended]
  • The average protein intake was 15.9% of total calories for men and 15.5% of total calories for women. [Note: 10-35% is recommended]
  • The average fat intake was 33.6% of total calories for men and 33.5% of total calories for women. [Note: 20-35% is recommended]
  • Energy (calorie) intake appeared to be relatively stable over the 10-year period from 1999-2008; there were no statistically significant linear increases or decreases in total energy (calorie) intake.
  • Average carbohydrate intake decreased significantly over the 10-year period from 1999-2008 in both men and women.
  • Average protein intake increased significantly over the 10-year period from 1999-2008 in both men and women. 

What? Calorie intake hasn't increased over the past 10 years? We're not eating more carbohydrates (sugar-sweetened beverages, cakes, cookies, candy)? So why then is our population becoming increasingly obese? To answer these questions I sat down with our nutrition epidemiologist to come up with some possible explanations.

  1. Maybe it's not changes in dietary intake or composition, but rather decreases in physical activity and increases in sedentary behaviors that explain the rising obesity rates.
  2. Maybe the individuals involved in the study underreported what they eat. While one could argue that a similar number would have underreported in 1999 and 2008, studies have shown that overweight/obese people underreport more than normal weight people. Thus, more overweight/obese people in 2008 would mean more underreporting.
  3. According to the figures in the report, it looks like energy (calorie) intake peaks around the 2005-2006 survey (at least in men). It's possible that public health messages and policies in recent years are having some effect on energy (calorie) intake.
  4. The trend in decreases in calories from carbohydrates might be explained by the relatively high carbohydrate intake in 1999. Previous dietary messages focused on getting people to decrease fat intake and increase carbohydrate intake (e.g., low-fat diets, increase in low-fat food products).
  5. Low-carbohydrate diets are more popular today, which may result in lower trends in carbohydrate intake despite possible increases in refined carbohydrates like sugar-sweetened beverages, cakes, candies, etc.
  6. Maybe slight variations in energy (calorie) intake and food composition (that could not be detected with this large, population-based study) along with significant decreases in physical activity do have a big impact on weight.

What do you think? Share your thoughts on The Cooper Institute's Facebook page!

1Wright, J.D. (2010). Trends in intake of energy and macronutrients in adults from 1999-2000 through 2007-2008. National Center for Health Statistics Data Brief, 49, 1-7.