Do Negative Calorie Foods Exist?

Listen to this article on Spotify, watch it on YouTube, 或者用中文读。

Negative calorie foods are the idea that there are some foods that are so low in calorie density, that just by eating them, you would burn more energy digesting the food, than what the food would provide.

But do these foods exist? And if so, what might they be? Let’s take a practical look at “negative-calorie” foods.

Energy for metabolism

The theory behind negative calorie foods rely mostly on the fact that our bodies require some energy to process the food we eat.

There is physical energy being used, from the chewing of our food, to the movements of our stomach and intestines to move the food through our digestive system.

There is also chemical energy being used, from the hormones produced when it detects the food we eat, to the enzymes that are produced to break that food down.

All this extensive processing and activity generates some heat, which we call thermogenesis. This is why sometimes after a large meal, we might feel sweaty and hot.

We refer to all this energy lost from breaking down food as the thermic effect of food. However, it’s important to know that the magnitude of this thermic effect depends heavily on what we’re eating.

For example, a large Christmas dinner meal consisting of turkey meat, mashed potatoes and gravy, peas, and roasted vegetables, will require a multitude of enzymes and gastric movements to break it all down.

In another example, a small lunch salad consisting of leafy greens, bell peppers, cucumbers and some berries, will require far less enzymes, and need to process a much smaller volume of food.

So the large Christmas meal is going to have a much larger thermic effect than the small lunch salad.

The body is able to adjust the amount of energy it uses to process the food you eat, depending on what you’ve eaten.

Low calorie dense foods

The theory also depends on foods that are so low in calorie density, that processing these foods would potentially cost more calories than what the food provides.

Commonly cited foods include those with very high water content, and provide a low amount of calories per volume. Things like celery, cucumber, lettuce, cabbage, lemon, lime, the list goes on.

However, the fact that these foods are mostly water, and contain a very low amount of other macronutrients, like protein, fat, or carbohydrate, means that the body doesn’t really need to do a whole lot to process them. It doesn’t need to release any enzymes to help digest protein or fat, and most of the water is absorbed passively.

So the thermic effect of these low calorie foods is minimal, and studies suggest that the energy used to process these foods in our body do not surpass the amount of energy these foods provide, even with the small amounts they do provide.

That being said, these foods often provide a good amount of appetite suppressing soluble fiber, as well as plenty of water, two things you should be looking to increase to help you manage hunger, and reduce your intake of other calorie dense foods.

So even though these foods are not truly negative calorie foods, increasing their intake can still help you to lose weight.

What about chewing gum?

Another commonly cited negative calorie food is sugar free chewing gum, with the idea that the energy burned from chewing the gum would burn more calories than then gum can provide.

Research suggests that chewing burns about 11 kcal per hour. That’s not very much, unfortunately.

You burn 11 kcal by walking for about 3 minutes. So if you’re just chewing on a completely flavorless piece of gum for an hour trying to burn calories, you might want to just go for a walk instead.

However, chewing on gum is a good strategy used for individuals trying to avoid snacking too often. Chewing gum might help habitual snackers to keep their mouth and mind occupied, so they don’t reach for a cookie instead.

So while chewing sugar-free gum may not be the most efficient way to burn calories, it can serve as a good way to prevent snacking on your weight loss diet.

What about cold water?

Yet another commonly cited negative calorie drink is cold water, with the belief that your body will use more energy to heat and absorb the water than the water can provide.

Water is passively absorbed by the body, meaning it doesn’t really need to use a whole lot of energy to absorb it.

So let’s take a look at the energy required to heat the water up to body temperature.

We know that it takes 1 kcal to increase 1 liter of water by 1 deg C.

So let’s say you drank 1 L of ice cold water currently at 1 deg C.

Your body needs to raise the 1 deg C water to 37 deg C, which is body temperature. This means it needs to raise it by 36 deg C.

This means that your body would burn 36 kcal to heat that 1 liter of ice cold water.

So drinking 1 L of ice cold water might burn about as many calories as a 6 minute walk.

Again, the energy used is pretty modest, and this is in an ideal world.

Some research suggests our bodies don’t actually burn nearly that much when drinking cold water, with some real life estimates suggesting the actual amount burned is 4-5 times less.

So drinking 1 liter of ice cold water might only be burning as much as a 1-2 minute walk.

That being said, studies that look at increasing water intake during a diet, show that it can help with weight loss. However the way it does so is more likely due to three other reasons:

1. Replacing other sugary drinks like pop, juice, or bubble tea with water, thereby reducing the amounts of sugars and empty calories you’re consuming.
2. Drinking water before and during meals to help partially fill out and bulk the stomach with water, and reduce the total amount of food eaten during the meal.
3. Sipping on water to help better manage hunger and suppress appetite in some people, thereby preventing overeating and snacking.

So increasing your water intake is indeed beneficial for your weight loss, however it’s primary benefits may not be necessarily as a negative calorie drink.

Summary of negative calorie foods

So how do we look at this objectively? Well, the rationale that these foods work by making the body work harder to digest them is not likely the main reason why these foods are great on your weight loss diet.

However, just because they may not work great as actual negative calorie foods doesn’t mean you shouldn’t bother with them. In fact you should still probably increase their usage in your diet.

• Low calorie vegetables like celery or cucumber provide a good amount of soluble fiber to bulk out your stomach and create fullness.
• Chewing gum can help distract your mouth and reduce your unwanted snacking and cravings.
• Drinking water will be very important to ensure you remain hydrated on your diet, as well as help to manage hunger and appetite.

Learn more about

• Dietary fiber: an overview
• Other foods for weight loss

See also

• 
  Doctor Reviews: Bee Bread
  Bee bread is fermented bee pollen, and may be quite nutritious, but lacks any researched health benefits in humans.
• 
  Arsenic in rice
  Rice often contains trace amounts of arsenic. White rice, and basmati rice from California, India, and Pakistan, tend to have lower amounts.
• 
  Mercury in fish and seafood
  Mercury is found in nearly all seafood, however tend to be in the highest concentrations in top-feeding, predatory fish, like shark and tuna.
• 
  Best Sugar Substitutes for Weight Loss
  Natural sweeteners may be better for health than artificial sweeteners, however using sugar substitutes does not support weight loss.
• 
  The Glycemic Index Diet: an overview
  The Glycemic Index diet focuses on foods that are lower in glycemic index and load, which can help with diabetes and weight loss.