What has no calories?: Separating dietary facts from myths

October 31, 2025 •

4 min read

Despite popular belief, there is no such thing as a truly zero-calorie food, with the singular exception of plain water. This article separates fact from fiction by addressing the common question, "What has no calories?", and exploring the scientific truth behind popular diet myths.

Quick Summary

This article debunks the myth of zero-calorie foods, explaining that only plain water is truly calorie-free. It covers how artificial sweeteners and high-fiber vegetables are considered effectively zero or very low in calories due to how the body processes them, clarifying common nutritional misconceptions.

Key Points

Water is the only true zero-calorie substance: Plain water contains no energy-yielding macronutrients, making it genuinely calorie-free.
"Zero-calorie" labels follow FDA rounding rules: Products with fewer than 5 calories per serving can be legally labeled as zero-calorie, so they may contain trace amounts.
Artificial sweeteners are non-nutritive: Substances like sucralose and stevia are intensely sweet but pass through the body largely un-metabolized, providing no energy.
Black coffee and plain tea are effectively calorie-free: When consumed without milk, sugar, or other additives, these beverages contain a negligible number of calories.
"Negative-calorie" foods are a myth: Nutrient-dense, high-water foods like celery and lettuce are very low in calories but do not burn more energy to digest than they provide.
Focus on nutrient-dense foods for weight management: Rather than seeking zero-calorie items, prioritize whole foods that are low in calories but high in fiber, water, and nutrients to promote satiety.

What Exactly Are Calories?

To understand what has no calories, it's essential to first define what a calorie is. A calorie is a unit of energy used to measure the energy content of food and beverages. Your body needs this energy from macronutrients (carbohydrates, fats, and proteins) to perform all its functions, from thinking and breathing to running and digesting. Without calories, your body cannot function, making true zero-calorie 'foods' biologically non-existent.

Food manufacturers are permitted by the Food and Drug Administration (FDA) to label a product as "calorie-free" if it contains fewer than 5 calories per serving. This rounding rule is why some items, like cooking sprays or certain mints, can technically contain trace amounts of calories but be labeled as zero.

The Exception: What is Truly Calorie-Free?

There is only one substance that is truly calorie-free for the human body: plain water.

Plain Water: Water contains no macronutrients and therefore provides no caloric energy. It is essential for hydration and numerous bodily processes, and drinking it can help replace high-calorie, sugary beverages, assisting with weight management.

Understanding Effectively Zero-Calorie Items

While not absolutely free of energy, some items are so low in calories or are processed in such a way that their caloric impact is negligible. They can be considered "effectively zero-calorie" and are often used as substitutes for higher-calorie ingredients.

Beverages

Black Coffee: A standard cup of plain, black coffee contains a minimal amount of calories, typically around 3-5 calories, which is considered negligible. However, adding cream, sugar, or flavored syrups dramatically increases the calorie count.
Plain Tea: Similar to black coffee, plain brewed tea made from Camellia sinensis leaves (like black, green, or oolong tea) is virtually calorie-free. As with coffee, sweeteners and milk will add calories.

Sweeteners and Flavorings

Artificial Sweeteners: Non-nutritive, high-intensity sweeteners like sucralose, aspartame, and saccharin are designed to provide intense sweetness without calories. This is because their molecular structure is not recognized or broken down by the body in the same way as sugar, so no energy is released.
Some Novel Sweeteners and Sugar Alcohols: Erythritol and monk fruit extract are examples of newer, naturally derived sweeteners that are either calorie-free or very low in calories, making them popular sugar substitutes. Erythritol contains just 0.24 calories per gram, which is why it can be labeled "zero-calorie".
Herbs and Spices: Most herbs and spices, such as cinnamon, garlic, and dried herbs, provide flavor with a negligible amount of calories per serving.

The Low-Calorie vs. Zero-Calorie Misconception

Many nutrient-dense fruits and vegetables are colloquially referred to as "zero-calorie" or "negative-calorie" foods due to their high water and fiber content, but this is a common misconception. While very low in calories, they are not zero.

The "Negative-Calorie" Food Myth

The myth of "negative-calorie" foods, such as celery or lettuce, suggests that the energy required to digest them is greater than the energy they contain, resulting in a net calorie deficit. Scientific evidence does not support this. The thermic effect of food (the energy needed for digestion) accounts for only a small percentage of total calorie intake, and it is impossible for it to exceed the total calories in the food itself.

High-Water and High-Fiber Foods

These foods are excellent for weight management because they offer significant volume and satiety for very few calories, not because they are calorie-free. They are packed with essential vitamins and minerals, making them a nutritious choice for any diet.

Vegetables: Celery, cucumber, lettuce, spinach, broccoli, and cauliflower are all examples of vegetables with a very high water content, making them extremely low in calories.
Fruits: Watermelon, strawberries, and grapefruit are fruits with a high water content and fewer calories per serving than many other fruits.

Low-Calorie Choices to Add to Your Diet

Instead of focusing on mythical zero-calorie foods, a healthier approach is to incorporate a variety of nutrient-dense, low-calorie options into your daily diet. These include:

Leafy Greens: Kale, spinach, and arugula are low-calorie and packed with vitamins and minerals.
Berries: Mixed berries are a great source of fiber and antioxidants with a relatively low-calorie count.
Soups and Broths: Clear broths, with or without added vegetables, can be a filling, low-calorie addition to a meal.

Truly Calorie-Free vs. Low-Calorie Foods


Feature	Truly Calorie-Free	Effectively Zero-Calorie	Low-Calorie (Often Misrepresented as Zero)
Energy Value	0 calories per serving.	< 5 calories per serving, rounded down.	Contains a small, measurable number of calories.
Examples	Plain water.	Artificial sweeteners (sucralose, etc.), black coffee, plain tea, erythritol.	Celery, lettuce, cucumber, broccoli, watermelon.
Macronutrient Content	Contains no carbohydrates, fats, or proteins.	No significant macronutrient content.	Contains some carbohydrates, fiber, and micronutrients.
Digestion Impact	Requires no energy for digestion.	Not metabolized for energy.	Requires some energy for digestion (thermic effect of food).
Key Benefit	Hydration, no calorie impact.	Sweetness/flavor without added energy.	High water/fiber for satiety; nutrient-dense.

Conclusion

While the search for a food that has no calories is a dead-end, the concept leads to a more meaningful understanding of nutritional science. Plain water is the only genuinely calorie-free substance, while a variety of beverages and sweeteners can be considered effectively zero due to FDA labeling rules and how the body metabolizes them. The popular "negative-calorie" foods like celery and lettuce are, in fact, low-calorie and high in nutrients, making them a great tool for managing overall caloric intake through satiety. The key to a healthy diet is not to pursue mythical zero-calorie items but to prioritize nutrient-dense, low-calorie foods and to be mindful of additives like sugars and creamers. Focus on balanced nutrition rather than calorie-hunting for a more sustainable and healthy eating pattern. A balanced approach to nutrition, centered on whole foods, is far more beneficial for long-term health.

For further information, the CDC provides extensive resources on healthy eating and hydration for managing weight.

Frequently Asked Questions

No, celery is not a negative-calorie food. This is a common myth. While it is very low in calories and high in water and fiber, your body does not burn more energy to digest it than the celery provides.

Plain black coffee and tea are essentially calorie-free, with only 3-5 calories per cup for coffee and nearly none for tea. They are safe to consume if you're keeping calorie intake minimal, as long as you don't add cream, sugar, or other additives.

Artificial sweeteners are calorie-free because the body does not metabolize them for energy. Their molecular structure is different enough from sugar that they bind to sweet receptors on the tongue but are not broken down in the same way, so they pass through the body without contributing calories.

According to FDA labeling laws, a product with fewer than 5 calories per serving can be labeled as zero-calorie. Diet sodas contain artificial sweeteners that provide no energy and fall under this rule. However, they lack nutritional value and may have other health implications.

The best and most beneficial zero-calorie drink is plain water. It provides essential hydration without any additives or concerns associated with artificial sweeteners. You can also opt for plain unsweetened coffee or tea.

Dietary fiber, particularly soluble fiber, can provide some calories, but fewer than digestible carbohydrates. Insoluble fiber has little to no caloric impact. For most people on a typical diet, the calories from fiber are not a significant concern, but labeling rules can cause discrepancies.

Foods high in water and fiber, like lettuce and cucumber, promote satiety by filling you up and providing bulk without a high-calorie count. This helps reduce overall caloric intake, making it easier to manage weight.