advertisement



Q & A Library


Print this page | Sign up for free e-bulletins
 | Bookmark This Page

Q
Are Calorie Counts Accurate?

I've heard that the calorie counts listed on packaged food often misrepresent the actual number of calories these items actually provide. Are there particular foods that are higher or lower in calories than we're led to believe?

A
Answer (Published 4/16/2013)

Calorie counts aren't as simple – or as reliable – as you might think. In fact, there is considerable scientific debate about what to make of current calorie counts. (For the record, what we think of as a calorie is actually a kilocalorie, the amount of energy needed to raise the temperature of one kilogram of water one degree Celsius.)

Related Weil Products
Dr. Weil's Spontaneous Happiness for Your Healthy Body - It's the journey not the destination. Make each day count, with an outlook that is both serene and inspired. Dr. Weil's new website, SpontaneousHappiness.com, has everything you need to get on the path to optimal well-being including recipes, checklists and exclusive tools to track your walking. Learn more, start your 10-day free trial now.

Determining the caloric value of specific foods gets quite complicated once you consider the differences between human metabolism and laboratory analysis. For example, cooked and processed foods are higher in calories than raw food, because it is easier for us to consume cooked foods and extract the nutrients they contain. Calorie counts as we know them don't take into consideration the energy (calories) we burn in chewing and digesting food. For example, it takes more energy to metabolize protein than it does to metabolize carbohydrates and fats. For all animals (including humans) the energy "cost" of digesting and metabolizing a meal comes to between five and 30 percent of the meal's energy (the calories it provides), according to Stephen M. Secor, Ph.D., an associate professor at the University of Alabama who studies digestive processes.

Another issue: since we don't completely digest some foods, how many of the calories they contain should we actually count? In a study published in 2012 in the American Journal of Clinical Nutrition, Janet Novotny, a U.S. Department of Agriculture (USDA) research physiologist, reported that the fat in almonds is not completely digested, and for that reason, a 28-gram (roughly one ounce) serving of almonds gives us 129 calories, 32 percent fewer than the 168-170 estimated by Wilbur Atwater, the 19th century USDA scientist who established calorie counts.

On a practical level, we know that eating any amount of foods with a high glycemic index (mainly refined carbohydrates) make you hungrier sooner than you would be if you had eaten a serving of whole grains with a similar calorie count. As a result, you're likely to overeat, possibly taking in even more high-calorie, high-glycemic-index carbs.

Does this mean reported calorie totals are useless? Not at all. In 2012, my friend Marion Nestle, M.P.H., Ph.D., author and professor in the department of nutrition, food studies and public health at New York University, co-authored a book titled, Why Calories Count: From Science to Politics  (University of California Press). Dr. Nestle and her co-author, Malden Nesheim, Ph.D., emeritus professor of nutrition at Cornell University, have reviewed all the research and concluded that estimates based on the Atwater calorie counts are "close enough." If you want to lose weight, Drs. Nestle and Nesheim conclude, "Eat less; it works every time."

I agree. The obesity epidemic in the U.S. does not stem from miscounting calories but from eating oversized portions and too many processed and refined foods, especially high-glycemic-index carbohydrate foods that disturb metabolism.

Andrew Weil, M.D.

Creative Commons License Some Rights Reserved Creative Commons Copyright Notice
A portion of the original material created by Weil Lifestyle, LLC on DrWeil.com (specifically, all question and answer-type articles in the Dr. Weil Q&A Library) is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

The Weil Vitamin Advisor
Get your FREE personalized vitamin recommendation & supplement plan today!

Dr. Weil on Healthy Aging
Your Online Guide to the Anti-Inflammatory Diet. Start eating for your health - begin your free trial now.

Dr. Weil's Spontaneous Happiness
Achieve emotional well-being
in just eight weeks!
Start your 10-day free trial now!

Vitamin Library
Supplement your knowledge with Dr. Weil's essential vitamin facts. Learn why they are necessary and more.

Dr. Weil's Optimum Health Plan
Your 8-week plan to wellness.
Begin your journey today!
 

Dr. Weil's Head-to-Toe
Wellness Guide

Your guide to natural health.
Use the Wellness Guide today!

Dr. Weil's Anti-Inflammatory Diet Food Pyramid
Our interactive tool can help improve overall health through diet.

Condition Care Guide
Learn about health conditions from acne to vertigo, and Dr. Weil's view of the best treatment options for each.

Healthy Recipes
Discover a treasure trove of healthy, healing foods and creative, delicious ways to prepare them.

Q&A Library
Over 2,000 questions from you
and their corresponding answers
from Dr. Weil.

 
Copyright © 2014 Weil Lifestyle, LLC
Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

Ad Choice
Advertising Notice

This Site and third parties who place advertisements on this Site may collect and use information about your visits to this Site and other websites in order to provide advertisements about goods and services of interest to you. If you would like to obtain more information about these advertising practices and to make choices about online behavioral advertising, please click here