“Negative-calorie foods” are foods that purportedly take more calories to eat and digest than they provide your body.

Many dieters eat them because they believe doing so causes fat loss.

Not everyone buys the hype about negative-calorie foods, though.

Detractors argue that no food can create a calorie deficit on its own. They admit that eating these so-called negative-calorie foods has health and weight-loss perks, but claim they won’t alone boost weight loss.

Who’s right?

Get an evidence-based answer in this article.

What Is A Calorie?

A calorie is a unit of energy.

More precisely, it’s the energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius.

We typically use calories to measure the energy content of food and the amount of energy our bodies burn performing functions such as breathing, digesting food, and physical activity.

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What Are “Negative-Calorie Foods?”

A “negative-calorie food” (or “calorie-negative food”)  is any food that allegedly requires more calories to eat and digest than it provides your body.

For example, if a food contains 50 calories, but your body burns 60 calories chewing and digesting it, it would be considered a negative-calorie food. 

If negative-calorie foods exist, eating them could help you lose fat by creating a calorie deficit.

What Are “The 10 Negative-Calorie Foods?”

This negative-calorie foods list commonly appears in articles about negative-calorie foods and contains the 10 foods that many people believe “cost” more calories to digest than they contain:

  1. Celery
  2. Lettuce
  3. Cucumbers
  4. Broccoli
  5. Carrots
  6. Grapefruit
  7. Tomatoes
  8. Watermelon
  9. Apples
  10. Berries

Do Negative-Calorie Foods Exist?

Probably not.

Many so-called negative-calorie foods are low in calories, but there’s no evidence they require more calories to eat and digest than they contain. 

For instance, one common argument for negative-calorie foods is that some foods contain so few calories that you likely burn more calories chewing them than they provide.

While it’s true that chewing food burns calories, a study published in The New England Journal of Medicine shows that it probably doesn’t burn enough to make a food “negative-calorie.”

That study showed that chewing gum for an entire hour only burned about 11 calories. At that rate, you’d have to munch on a stick of celery (which contains ~6 calories) for around 30 minutes to burn the calories it contains. 

Since most people chew for only a few minutes per meal, we can safely assume that the number of calories you burn chewing doesn’t exceed the number of calories in the food you’re eating.

People often also suggest that some foods are negative-calorie because they “cost” more to digest than they supply.

However, research shows that the calories you burn digesting food (a food’s “TEF”) are just a fraction of the calories the food contains. Specifically, protein has a TEF of ~20-to-30%, carbs have a TEF of ~5-to-10%, and fat has a TEF of ~0-to-3%.

This means, for example, that if you eat 100 calories of protein, your body burns 20-to-30 calories digesting it.

In other words, digestion never accounts for more calories than a food provides. This is especially true for many foods that people term negative-calorie since these foods are usually high in carbs but contain little protein, making their TEF relatively low. 

Furthermore, most negative-calorie foods contain a lot of fiber, so they typically cost fewer calories to digest than low-fiber foods. 

In the final analysis, there’s no direct evidence that negative-calorie foods don’t exist. Based on what research tells us about how many calories we burn chewing and digesting food, however, we can be quite sure there’s no such thing as a negative-calorie food.

That doesn’t negate the value of these foods, though. While they aren’t a quick fix for weight loss, there are still good reasons to incorporate them into your diet.

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Should You Eat “Negative-Calorie Foods” for Weight Loss?

Yes.

But not because they’re “negative-calorie.” 

The key reason to eat these foods while dieting is they’re usually high in fiber and low in calories.

Thus, eating negative-calorie foods can help temper your appetite and make eating in a calorie deficit feel less challenging.

Also, these foods often contain ample vitamins and minerals. Although these nutrients don’t directly boost weight loss, they contribute to your overall health while “cutting,” increasing the chances you’ll stick to your diet.

Another advantage of eating negative-calorie foods is they tend to be unprocessed. This is significant because research shows that eating a diet rich in unprocessed foods maximizes the number of calories you burn through TEF.

Again, this isn’t enough to create a calorie deficit alone, but it should make losing weight easier, provided you also know how to diet and train to drive fat loss. 

That said, your diet shouldn’t only consist of negative-calorie foods. 

As I explain in my fitness books for men and women, Bigger Leaner Stronger and Thinner Leaner Stronger, to make dieting for weight loss as fast, healthful, and sustainable as possible, you should aim to eat a range of nutritious foods, including fruits, vegetables, whole grains, lean meats, fish, dairy, pulses, nuts, seeds, legumes, and plant oils.

With effective meal planning, you should be able to include regular “treats” as well.

And if you’d like specific advice about which foods you should eat to reach your health and fitness goals, take the Legion Diet Quiz, and in less than a minute, you’ll know exactly what diet is right for you. Click here to check it out.