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Negative Calorie Foods

The more you eat, the more you lose. But wait—there’s a catch.

By
Monica Reinagel, M.S.,L.D./N,
January 21, 2009
Episode #027

Here’s the 411 on negative-calorie foods: Digesting food burns calories. A few foods, such as grapefruit and celery, contain fewer calories than it takes to digest them. So, when you eat these foods, you actually burn more calories than you take in. Thus, the term “negative-calorie foods.”

Theoretically, the more negative-calorie foods I eat, the more weight I lose! How great is that? Now all I need is a job that pays me more the less I do and a bank account that gets bigger the more I spend!

Unfortunately, it doesn’t work that way. Here’s why: When nutritionists estimate how many calories you should eat, we’re already taking into consideration how many calories you burn chewing and digesting your food. The “negative-calorie diet” essentially subtracts those calories twice. That’s the kind of accounting that will make you bounce checks (or, get you a really good job on Wall Street).

How Negative Calorie Foods Help You Lose Weight

But will eating a whole bunch of celery and grapefruit speed your weight loss? Only if you eat them instead of brownies and potato chips. In other words, you can’t eat a brownie and then burn off the calories by chasing it with a hundred sticks of celery. The only way to make this work is to eat the hundred sticks of celery first. Then, with any luck, you’ll be too full to eat the brownie.

Replacing high-calorie foods with low-calorie foods will help you lose weight because it reduces your overall calorie intake. Of course, you can also lose weight by exercising, which burns calories. But digesting negative-calorie foods does not constitute an exercise program. Take it from me: A half hour spent on the treadmill or bike is going to burn a lot more calories than a half hour spent digesting celery.

Those lists of negative-calorie foods you’ll find on the Internet are simply lists of low-calorie foods. And, if you’re dieting, these kinds of foods are your friends. To that end, I’ll include a link to a list of negative-calorie foods in the show notes. But I’m afraid that a negative-calorie diet is, indeed, to good to be true.

Want to Lose Weight? Chill! 

While you’re looking up negative-calorie foods on the Internet, you’ll eventually come across the claim that drinking ice water will also speed weight loss. The idea here is that your body has to burn calories in order to warm the ice water up to body temperature. True enough. But before you get too excited, let’s do the math.

Depending on how long it’s been since you were in high school, you might still have a dim memory of the definition of a calorie. A calorie is the amount of energy it takes to raise the temperature of 1 gram of water by 1 degree Celsius.

A 16-ounce glass of water is about 470 grams. The temperature of ice water is 0 degrees C. and body temperature is 37 degrees C. Thirty-seven times 470 equals 17,390 calories! Wow! That’s a whole lot more calories than you can burn in a half hour on the treadmill. But, there’s a small wrinkle.

When we talk about Calories in relation to food and nutrition, we’re really talking about kilocalories, or kcals. A stalk of celery, for example, actually contains 6,000 calories. To save the effort of writing all those zeros, we just say that a stalk of celery contains 6 kcals. In popular use, kcals are also referred to simply as Calories, but with a capital “c.”

So, drinking a glass of ice water burns just 17 kilocalories. To lose one pound, you’d have to drink 205 glasses of ice water. And even that isn’t quite accurate because we include the energy it takes to maintain your body temperature when we calculate how many calories you should be eating.

Fidget Your Way to Weight Loss

We’re almost out of time and I don’t want to leave you with nothing but deflated dietary dreams. Want to lose weight faster? Forget the negative-calorie foods and ice-water. Instead, learn to fidget! That’s right! People who are naturally fidgety burn more calories than those who aren’t. And, unlike digesting celery or warming up ice water, fidgeting can actually add up to significant calorie burn.

Instead of sitting quietly through concerts, movies, meetings, or long plane trips, drum your fingers, tap your toes, bounce your legs, wiggle, squirm, and pace around. According to researchers from the Mayo Clinic, diligent fidgeting can burn several hundred calories a day. It could also cost you your job or your marriage but, hey, you can’t have everything!

And, of course, for more tips on weight loss you can check out The Get-Fit Guy's page right here on the Quick and Dirty Tips website.

This is Monica Reinagel, the Nutrition Diva, with your quick and dirty tips for eating well and feeling fabulous. If you have a nutrition question for me, send an email to nutrition@quickanddirtytips.com.  I can also be reached on Facebook or Twitter.

Have a great day and eat something good for me!

RESOURCES:

Negative Calorie Foods (Take with a grain of salt!)

History of the Calorie in Nutrition (Journal of Nutrition)

How Fidgeting Helps You Stay Slim (The London Independent)

Celery image courtesy of Shutterstock.

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