A lot of time and effort have gone into determining calorie counts over the years. But new research suggests they may be wrong. More precisely, the research, done by Richard Wrangham of Harvard University, indicates cooking food increases its calorie count, possibly by as much as 25 to 50 percent. And he's not talking about the water-versus-fat issue dietician Jessica Cox mentioned in the previous section.
Wrangham asserts past scientists never considered the caloric cost involved in the digestive process. Your body spends a lot of energy digesting, say, a raw carrot or raw piece of beef. But if you cook these foods, they soften, and your body expends fewer calories digesting them. Thus, the net effect is that you've taken in more calories from a cooked meal of beef and carrots than from the raw version [source: Wrangham].
Another aspect of cooking food that past researchers overlooked concerns digestive enzymes. Our body can only digest what it can get its hands on. A raw potato, for example, has tightly packed starches that our digestive enzymes can't access. When cooked, however, those starches are gelatinized, releasing sugar-based molecules that our bodies can now feast upon, adding to our caloric intake. Similarly, cooking beef opens up its muscle proteins to our digestive enzymes. In addition, preparing food for cooking by chopping, grinding and the like also makes them more accessible to digestive enzymes [sources: Wrangham, You Beauty].
Wrangham and his associates also say their studies show the Atwater system for determining calories is flawed. For one thing, it ignores the bacteria in our stomach. When we eat food, our stomach's bacteria steal some of it to essentially feed themselves. Thus, less is left over for our body as a whole to take in, meaning we're getting fewer calories. The Atwater system also doesn't look at the effect of processing, assigning the same caloric value to, say, whole-grain wheat and highly milled flour. But since our bodies will use more energy digesting the whole-grain wheat, it should be assigned a lower caloric value.
Don't think this means a healthy diet should be composed of all raw foods, though. Yes, our bodies work harder to digest them, so eating a lot of raw foods means you're taking in fewer calories — definitely a bonus if you're trying to lose weight. But if you only eat raw foods, that can be problematic. One study Wrangham looked at showed those who ate a 100 percent raw-food diet were unhealthy. The average woman didn't have a functioning menstrual cycle, and half of the women stopped getting their period at all, suggesting they were taking in far too few calories. Moderation is the key, he says; a diet of both raw and processed foods is best.
Author's Note: How do they figure out the number of calories in a recipe?
When I was a young woman, I wanted to lose weight. On the advice of some friends, I decided to tally my daily caloric intake and limit myself to 1,200-1,500 calories per day. This was the pre-Internet era, so I bought several tiny booklets listing the calorie counts of various food items. (Back then, these booklets commonly sat in front of the grocery store check-out counters alongside the Hollywood tabloids.) I memorized the calories in foods I regularly ate (banana = 100, apple = 60, egg = 90), then calculated the caloric value of recipes as I made them, jotting them down on my recipe cards. The system worked for me, and I lost 12 pounds.
Today, there are loads of websites that list calorie counts, plus will instantly calculate all of the nutrition facts for any recipe you input. One, at CalorieCount.com, will even create a nutrition label for you! I wish the Internet had been around back then. On the other hand, using those booklets so often helped me to memorize the calorie counts in most of the foods I eat, which has helped me maintain a healthy weight for many years.
More Great Links
- American Heart Association. "What is a Serving?" Dec. 18, 2014. (Nov. 17, 2015) http://www.heart.org/HEARTORG/Caregiver/Replenish/WhatisaServing/What-is-a-Serving_UCM_301838_Article.jsp#.Vku0edKrSUk
- Avila, Jim and Serena Marshall. "Calorie Counts: How Accurate Are They?" ABC News. Jan. 8, 2013. (Nov. 11, 2015) http://abcnews.go.com/Health/calorie-counts-accurate/story?id=18164180
- Calorie Count. "My Recipes." (Nov. 10, 2015) http://www.caloriecount.com/cc/recipe_analysis.php
- Cox, Jessica. Registered dietician nutritionist and culinary dietician. Email interview.
- Federal Register. "Food Labeling; Nutrition Labeling of Standard Menu Items in Restaurants and Similar Food Establishments; Extension of Compliance Date." July 10, 2015. (Nov. 20, 2015) https://www.federalregister.gov/articles/2015/07/10/2015-16865/food-labeling-nutrition-labeling-of-standard-menu-items-in-restaurants-and-similar-retail-food
- FitClick. "How Many Calories In Your Food?" (Nov. 9, 2015) http://www.fitclick.com/how_many_calories#.VkD0ftKrSUk
- MyFitnessPal. "Recipe Nutrition Calculator." (Nov. 9, 2015) http://www.myfitnesspal.com/recipe/calculator
- Samuelson, Tracey. "How restaurants calculate calorie counts." Marketplace. Nov. 25, 2014. (Nov. 9, 2015) http://www.marketplace.org/topics/business/how-restaurants-calculate-calorie-counts
- Schechner, Sam. "How Do They Measure Calories?" Slate. April 21, 2004. (Nov. 9, 2015) http://www.slate.com/articles/news_and_politics/explainer/2004/04/how_do_they_measure_calories.html
- Scientific American. "How do food manufacturers calculate the calorie count of packaged foods?" July 31, 2006. (Nov. 9, 2015) http://www.scientificamerican.com/article/how-do-food-manufacturers/
- Spark Recipes. "Try our Recipe Calculator!" (Nov. 10, 2015) https://recipes.sparkpeople.com/recipe-calculator.asp
- Tufts University. "Calculating Calories and Nutrients in Meals." (Nov. 9, 2015) http://hnrca.tufts.edu/restaurant-meal-calculator/
- United States Department of Agriculture. "Welcome to the USDA National Nutrient Database for Standard Reference." Dec. 7, 2011. (Nov. 9, 2015) http://ndb.nal.usda.gov//
- U.S. Food and Drug Administration. "FDA finalizes menu and vending machine calorie labeling rules." Nov. 25, 2015. (Nov. 9, 2015) http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm423952.htm
- Wilcox, Christie. "Does Cooked Food Contain More Calories?" YouBeauty. Jan. 17, 2012. (Nov. 9, 2015) http://www.youbeauty.com/nutrition/does-cooked-food-contain-more-calories/
- Wrangham, Richard. "Why Calorie Counts Are Wrong: Cooked Food Provides a Lot More Energy." Discover Magazine. Dec. 8, 2011. (Nov. 9, 2015) http://blogs.discovermagazine.com/crux/2011/12/08/why-calorie-counts-are-wrong-cooked-food-provides-a-lot-more-energy/#.VkEJrdKrSUk