Negative Calorie Foods – Are They Real?

Almost everyone trying to lose weight keeps track of their calorie intake. The basic idea is that if you consume fewer calories than you use, then you will lose weight. Of course, this can be taken to an unhealthy extreme, but the principle still stands.

According to common knowledge, some foods are “negative calorie”. In other words, they require more calories to digest than they contain. However, things are not quite as simple as they may first appear.

Negative Calorie Foods Explained.

When digesting food, your body uses energy and the amount of energy differs depending on the food. If a food takes more calories to digest than it contains, then you can theoretically lose weight just by eating them.

Generally, negative-calorie foods are believed to be fruit and vegetables with a high water content. Examples include:

  • Celery – 14 calories per 100g
  • Carrots – 52 calories per 130g
  • Lettuce – 5 calories per 35g
  • Broccoli – 31 calories per 90g
  • Grapefruit – 69 calories per 230g
  • Tomatoes – 32 calories per 180g
  • Cucumbers – 8 calories per 50g
  • Watermelon – 46 calories per 150g
  • Apples – 53 calories per 110g

The question is, do these foods truly contain fewer calories than it takes for your body to digest them?

Unfortunately, the answer is almost certainly no. While the foods are nutritious, it is unlikely that they are truly negative-calorie. Each contains calories and there is no evidence that it takes more calories to eat and digest them than they provide.

Does Eating Food Burn Calories?

Some people have hypothesised that the energy used to chew food could help them become negative calorie. There is a small amount of research that suggests that chewing gum can increase the energy your body uses by about 11 calories per hour. Therefore, when chewing the aforementioned foods, the amount of calories used is probably negligible.

When it comes to digesting foods, the amount of calories used is once again less than the calories the food provides. In actual fact, the amount of calories used to digest food is usually expressed as a percentage of the calories you eat, and the percentage is similar for carbs, fats and proteins. When it comes to carbs, about 5-10% is used to process the foods, 0-5% for fat and 20-30% for protein. Therefore, once again, when it comes to the foods listed above, it is highly unlikely that they are negative-calorie.

Are There Zero Calorie Foods?

There are some things that contain zero calories, such as water. Often, people will claim that cold water can help increase your metabolism. There is in fact research that supports the idea of small increases in metabolism for a limited time after drinking cold water. However, the increase is tiny; at most, it will be around 24 calories per hour. Furthermore, we cannot exist without calorie intake, so this is a dangerous strategy to utilise.

Aim for Nutritious Low-Calorie Foods

While the holy grail of negative calorie foods may not exist, the foods that people believe may be negative calorie are still nutritious. Furthermore, as they tend to have high water contents and few calories, you can eat larger amounts of them without consuming too many calories.

Here are a few more foods that are rich in nutrients and low in calories:

  • Kale – 7 calories per 20g and full of vitamins A, K and C, and various minerals
  • Blueberries – 84 calories per 150g, a good source of vitamins C and K, and manganese
  • Potatoes – 58 calories per 75g , a good source of potassium and vitamins B6 and C
  • Raspberries – 64 calories per 125g, a good source of vitamin C and manganese
  • Spinach – 7 calories per 30g, a good source of vitamins K and A, and several minerals

If you are looking for low-calorie protein sources, then consider the following:

  • Salmon – 121 calories and 17g protein per 85g serving and also contains omega-3 fatty acids and vitamins
  • Chicken breast – 110 calories and 22g protein per 85g serving
  • Plain Greek yoghurt – Fat free versions contain 100 calories and 16g protein per 170g serving
  • Whole eggs – 78 calories and 6g of protein per egg, together with vitamins, minerals and unsaturated fats.
  • Pork tenderloin – 91 calories and 15g of protein per 85g, as well as B vitamins and minerals

Furthermore, main of these protein sources also contain healthy fats. While fats may contain more calories per gram than protein and carbs, they are still an essential part of a healthy diet. You should also be trying to eat nutrient-rich whole foods, as they can also benefit weight loss and overall health. Furthermore, there is evidence that your body uses more calories when digesting whole foods than processed foods.

In short, rather than focusing on negative calorie foods, which most likely don’t exist, try to eat a balanced and nutritious diet, and you will still be able to lose weight while ensuring your body receives everything it needs.