Does Anything Have No Calories? Separating Fact from Fiction

October 15, 2025 •

4 min read

According to nutritional science, calories measure the energy potential in food. This raises the question: Does anything have no calories? The answer is more nuanced than a simple yes or no, as it depends on whether the item provides energy to the body, and most foods, even low-calorie ones, contain some form of energy.

Quick Summary

Pure water and approved non-nutritive sweeteners provide no caloric energy. So-called 'zero-calorie' foods like celery are just very low in calories, and the 'negative calorie' theory is unsupported by science. For weight management, focusing on nutrient-dense, low-energy-dense options is key.

Key Points

Water is the only true zero-calorie food substance: Plain water contains no energy-providing macronutrients (carbs, fats, proteins).
Non-nutritive sweeteners are calorie-free: Artificial and natural sweeteners like stevia, sucralose, and monk fruit contain no calories and are used in diet drinks.
'Zero-calorie foods' are a myth: So-called zero-calorie options like celery and cucumber are just very low in calories, not zero.
The 'negative calorie' theory is false: The idea that some foods burn more calories to digest than they contain is not supported by science.
Nutrient density is more important than chasing zero calories: Focusing on nutrient-dense foods (high vitamins, minerals, fiber) helps you feel full and satisfied with fewer calories overall.
FDA labeling rules: Foods can be labeled 'zero calorie' if they contain fewer than 5 calories per serving, leading to some confusion.
Fiber has minimal calories: While some fiber is fermented by gut bacteria, providing a small amount of energy, other fiber passes through undigested and contributes no calories.

The Science Behind Calories

Calories are units of energy that our bodies use for daily functions. This energy comes primarily from the three macronutrients: carbohydrates, fats, and proteins. Our bodies release this stored energy through digestion. For an item to have zero calories, it must be devoid of these energy-providing macronutrients. This brings us to the very short list of items that are truly calorie-free.

The Short List of Truly Calorie-Free Substances

There are indeed some things you can consume that have no caloric value. The most obvious is water, which is essential for life but provides no energy. However, other substances, mainly non-nutritive additives, also qualify.

Water: Plain water is pure and contains no fats, carbs, or proteins, making it a true zero-calorie substance. Sparkling water and plain mineral water also fall into this category, as long as no caloric flavorings are added.
Non-Nutritive Sweeteners: These are artificial or plant-derived sweeteners that provide a sweet taste without significant calories. Since they are many times sweeter than sugar, only tiny, non-caloric amounts are needed. Examples approved by the FDA include stevia, sucralose, erythritol, and monk fruit.
Diet Beverages: Most diet sodas and energy drinks use these non-nutritive sweeteners and are therefore calorie-free. However, some flavored or protein-enhanced waters may contain a few calories, so checking the label is essential.

Debunking the 'Zero-Calorie Food' Myth

Walk into any health food store or browse online, and you'll find lists of 'zero-calorie' or 'negative-calorie' foods like celery, cucumbers, and leafy greens. The truth is that while these foods are extremely low in calories, they are not zero. The misconception arises because they are high in water and fiber, which adds bulk and helps you feel full for very few calories. The body expends some energy digesting food, known as the thermic effect of food (TEF). However, the notion that some foods require more energy to digest than they provide is a widely circulated but scientifically unproven myth. Even with very low-calorie foods, the net energy gain is still positive, not negative.

Common low-calorie foods often cited as 'zero-calorie':

Celery (approx. 14 calories per cup)
Cucumber (approx. 8 calories per half-cup)
Lettuce (approx. 5 calories per cup)
Spinach (approx. 7 calories per cup)
Broccoli (approx. 34 calories per cup)

According to the FDA, if a food contains fewer than 5 calories per serving, it can be labeled as having zero calories. This is why many diet products carry a 'zero calorie' label even if they contain a minute amount of energy.

The Role of Fiber in Your Diet

Dietary fiber is a type of carbohydrate, but it's often treated differently when it comes to calories. Not all fiber is digested and absorbed by the body in the same way.

Insoluble Fiber: This type of fiber adds bulk to your diet and passes through the digestive tract largely unchanged. Since it isn't broken down for energy, it provides virtually no calories.
Soluble Fiber: This type of fiber dissolves in water and is fermented by bacteria in the large intestine. This process can produce short-chain fatty acids that provide a small amount of energy. The FDA estimates that fermentable fibers provide about 2 calories per gram, as opposed to the standard 4 calories per gram for other carbs.

Energy Density vs. Nutrient Density

Instead of chasing mythical 'zero-calorie' foods, a better strategy for weight management and overall health is to focus on nutrient density and energy density.


Feature	Calorie-Dense Foods	Nutrient-Dense Foods
Energy Level	High in calories per unit of weight or volume.	Low in calories per unit of weight or volume.
Nutrient Value	Often referred to as "empty calories"; high in fat and sugar but low in vitamins, minerals, and fiber.	Packed with essential vitamins, minerals, fiber, and other beneficial compounds.
Examples	Fried foods, sugary drinks, cookies, chips.	Vegetables, fruits, lean proteins, legumes, and whole grains.
Satiety Impact	Provides quick energy but can leave you feeling hungry sooner due to rapid digestion.	High in fiber and water, which helps you feel full and satisfied for longer on fewer calories.

A Better Approach: Volume Eating with Nutrient-Dense Foods

For those looking to manage their weight, the key is to prioritize volume and satiety rather than hunting for non-existent zero-calorie foods. Filling your plate with nutrient-dense foods allows you to consume more food for fewer calories, which promotes fullness and reduces overall calorie intake. A great way to start is by building meals around vegetables high in water and fiber, like those low-calorie options mentioned earlier, and pairing them with lean proteins and healthy fats for a balanced, satisfying meal. A balanced, sustainable approach to eating is far more effective than relying on diet fads.

For more information on high-fiber food options, consider reviewing authoritative sources like the Mayo Clinic's Guide to High-Fiber Foods.

Conclusion

Ultimately, the quest for a food item that has truly no calories is largely unsuccessful. The only consumables that can genuinely make this claim are water and non-nutritive sweeteners. The concept of 'zero-calorie' or 'negative-calorie' foods is a myth based on the low energy density of certain water- and fiber-rich vegetables. Rather than seeking a quick fix, focusing on a balanced diet rich in nutrient-dense, high-volume foods is the most sustainable and healthy approach to weight management and overall wellness.

Frequently Asked Questions

No, celery is not a zero-calorie food. It is often cited as one because it's very low in calories (approximately 14 calories per cup) and high in water and fiber. The energy required to digest it is minimal, not enough to create a 'negative calorie' balance.

No, non-nutritive sweeteners like stevia, aspartame, and sucralose are generally calorie-free. They are used in such small amounts that their energy contribution is negligible.

Calorie-dense foods are high in calories but low in beneficial nutrients like vitamins and minerals. Nutrient-dense foods, in contrast, provide a high amount of nutrients for a low number of calories, such as fruits and vegetables.

Water has zero calories because it contains no macronutrients—no carbohydrates, fats, or proteins—that the body can break down to release energy.

Most diet or sugar-free drinks use non-nutritive sweeteners and are calorie-free. However, some products, especially flavored or fortified waters, may contain a small amount of calories, so it is always best to check the nutrition label.

Fiber is a type of carbohydrate, but it's not fully digested. Insoluble fiber provides no calories, while soluble, fermentable fiber provides a very small number, about 2 calories per gram.

Incorporating low-calorie, nutrient-dense foods can aid weight management by promoting fullness with fewer calories. However, relying solely on them without a balanced diet and regular exercise is not a sustainable or healthy strategy.