The Truth Behind Negative Calorie Foods

Imagine a food that actually burns more calories than it provides, that helps you lose weight just by eating it. The idea sounds pretty good, doesn’t it? These so-called negative calorie foods have been promoted by many fitness books and diet plans. But do they work? Is there science to back this claim or is it just another fitness myth?

The Theory

Chewing and digesting food, as with all bodily functions, burns calories without us ever noticing. Certain foods, like celery or grapefruit, are high in dietary fiber but extremely low in calories, leading to the conclusion that they burn more calories than they actually provide.

The Reality

According to the Mayo Clinic, about five to 10 percent of your daily caloric expenditure goes toward chewing, breaking down and storing your food. The low-calorie options that populate the negative calorie food lists found all over the Internet do, in fact require energy to digest.

So, in theory at least, negative calorie foods exist. In practice, however, there is no scientific evidence to support the idea that a single food requires more calories to break down than it provides.

The real problem with this diet philosophy comes in the application. When people read that grapefruit is a negative calorie food that will burn calories for you, they react in one of two ways: Either they eat nothing but these negative calories foods, or they add it to their regular diets to try to counteract the calories from other foods.

Nothing In, Nothing Out

The first approach, loading your diet with almost exclusively negative calorie foods will absolutely make you lose weight. But this loss will be rapid and unhealthy. Diets that consist mainly of these foods are severely deficient in both total calories and vital nutrients.

These low-calorie, starvation diets can not be sustained for long periods of time and can even backfire. When your body enters starvation mood, your metabolism will slow down and actually start fighting to keep you alive by storing fat for energy.

You may also start to lose muscle mass, since that will be broken down for fuel as well.

Too Much of a Good Thing

The other application of negative calorie foods, tacking them onto otherwise unhealthy meals, isn’t much better. A 2010 study from Northwestern University’s Kellogg School of Management tested people’s perception of calories of meals both with and without a healthy side.

In one of the tests, subjects were asked to guess the calorie content of a bowl of chili. They estimated the value at about 699 calories. When the chili was served with a side of green beans, though, they placed the meal at 656 calories. In truth, the side of green beans probably didn’t add many more calories, but it certain didn’t detract any either.

The belief in negative calorie foods and the practice that it leads to could actually cause you to gain weight by ingesting more calories than you realize.

The bottom line: negative calorie foods as a diet philosophy is about as empty as it sounds. You won’t do yourself any good by trying to follow it, and you’re likely to do yourself some harm.

Do you have any experience with negative calorie foods? Please share your thoughts with us in the comments.


Should You Take a Multivitamin?

In 2011, Consumer Reports reported that Americans were spending about $5 billion per year on multivitamins. This means that roughly one third of the country’s population regularly takes multivitamins (which also generally contain minerals), making them the most commonly taken supplement in the U.S.A.

That level of popularity isn’t necessarily proof of a supplement’s safety or effectiveness, however — after all, at one point,many people were purposely ingesting tapeworm eggs. So, should you take a multivitamin? Although multivitamins are usually thought of as harmless, are there any potential side effects?

The Idea Behind Multivitamins

Your body needs a wide variety of nutrients to maintain the complex array of functions that keep you active and healthy. Generally speaking, these nutrients can be separated into two groups: macronutrients and micronutrients. Macronutrients are fats, proteins and carbohydrates. For the most part, they make up the fuel mixture for your body.

Micronutrients are a broad category, encompassing vitamins and minerals, among other things. These substances are vital to just about everything your body does, including maintaining bone health, nerve function, heart health, muscle contractions and hormone production.

A healthy, balanced diet will give most people all of the vitamins and minerals they need. However, eating a healthy and balanced diet is an increasingly difficult accomplishment, which means you may require supplementation to fill the gaps in your diet. It is important to note that true deficiencies in these vitamins and minerals are very rare in the United States. Certain diseases and conditions can create these deficiencies, though, with symptoms varying from nutrient to nutrient.

Some sources contend that athletes and people who live an active lifestyle will have an increased need for these micronutrients. There isn’t enough research yet to definitively state the vitamin and mineral needs of athletes, but it is apparent that vigorous activity causes your body to burn through these nutrients faster than it would otherwise.

Do They Work?

Whether or not you feel a multivitamin works will likely depend largely on your expectations. Unless you have a condition that increases your need for certain nutrients, you won’t see immediate or drastic changes in your physical or mental well-being; multivitamins are more about maintenance than dramatic change.

The role that these micronutrients play can be compared to the various fluids in your car. Oil, brake fluid, power steering fluid, transmission fluid and coolant all need to be kept at proper levels for your car to run smoothly. If one of these gets low, you’ll probably notice a change in your car’s gas mileage, maybe accompanied by a new smell or noise. If you top off these fluid levels, you most likely won’t notice any major changes — but the benefits are still there, and your car will probably last longer.

In the same way, it seems that multivitamins encourage healthy aging. One Australian study found that taking multivitamins for eight weeks improved memory and slowed cognitive decline in men aged 50 to 69. Another study in The American Journal of Clinical Nutrition showed that women using multivitamins increased the length of their telomeres, which are nucleotide sequences that protect chromosomes from deterioration — essentially increasing the lifespan of cells and potentially slowing the aging process.

Potential Side Effects

It is possible to overdose on some of the nutrients found in multivitamins, such as iron, so they should always be taken in the recommended doses and according to directions. As with all supplements, multivitamins should only be taken after discussion with your doctor, especially if you have a condition and are taking medication. Allergies to multivitamins are also possible.

There are also some concerns that multivitamins may increase the risk of breast cancer in women, but this is highly contested, and many studies contradict each other.

Have you taken multivitamins? Did you feel they worked for you? Please share your experience in the comments.