What food has 0 calories? Separating nutrition fact from fiction

October 9, 2025 •

5 min read

While the idea of consuming food with absolutely no energy is appealing, a dietitian from Peace & Nutrition clarifies that water is the only truly zero-calorie item, with packaged foods labeled as such permitted to contain up to 5 calories per serving. This article will delve into the reality behind so-called "zero-calorie" and "negative-calorie" foods.

Quick Summary

Despite popular belief, foods with a true zero-calorie content do not exist, apart from water and certain non-caloric beverages. Many items marketed this way are simply very low in calories, high in water and fiber, and mislabeled due to regulatory guidelines. This approach can help manage intake but should not replace a balanced, nutrient-dense diet.

Key Points

Zero-Calorie Myth: With the exception of water and certain non-caloric beverages, no food is truly zero-calorie.
The FDA Labeling Rule: Foods containing less than 5 calories per serving can be legally labeled as "zero calorie".
The Negative-Calorie Myth: The concept that some foods require more energy to digest than they provide is scientifically false. The thermic effect of food is a small fraction of its total calories.
Low-Calorie, High-Volume Foods: Focus on nutrient-dense foods like fruits and vegetables that are high in water and fiber. They promote satiety and help with calorie management.
Balanced Diet Over Restriction: A healthy and sustainable approach is to incorporate a variety of nutrient-rich foods, including low-calorie options, alongside healthy fats and proteins, rather than relying solely on a restrictive list.

The search for foods that can be eaten freely without contributing to a daily calorie count is a common one, but it's based on a pervasive nutrition myth. Understanding the distinction between truly calorie-free options and extremely low-calorie foods is key to building a sustainable and healthy eating plan. This guide will debunk the popular misconceptions and focus on the scientifically sound benefits of incorporating nutrient-dense, high-volume foods into your diet.

The Myth of Negative-Calorie Foods

The concept of a "negative-calorie" food is that the energy required to chew and digest it is greater than the energy it provides. While this sounds like a clever weight-loss hack, scientific evidence has repeatedly debunked this idea.

Thermic Effect of Food (TEF): It's true that your body expends energy to process food, a phenomenon known as the thermic effect of food (TEF). However, this effect is much smaller than the total calories the food contains. For carbohydrates, TEF is only 5–10% of the food's calories; for fat, it's even lower, at 0–5%.
No Evidence to Support the Claim: Research has confirmed that even low-calorie foods like celery are not negative-calorie. A study using bearded dragons with similar digestive systems to humans found that the lizards still absorbed a significant percentage of the celery's energy. For a person to even offset their basal metabolic rate with just celery, they would need to eat an impossibly large amount.

The Reality of Low-Calorie, Nutrient-Dense Foods

Instead of chasing a nonexistent myth, the focus should be on leveraging the benefits of low-calorie, nutrient-dense foods. These items, often vegetables and fruits, are packed with vitamins, minerals, and fiber, and are very high in water content. This combination is what makes them so valuable for weight management.

High Satiety: Fiber and water increase the volume of food without adding calories, helping you feel full and satisfied for longer periods. This can naturally lead to reduced overall calorie intake.
Essential Nutrients: Unlike a diet focused on processed, artificially calorie-free products, consuming these whole foods ensures you're getting a wide array of essential vitamins, minerals, and antioxidants. This supports overall health, beyond just weight control.

The Zero-Calorie Drink Exception

When it comes to liquid intake, there are a few options that truly offer zero calories. These are vital for hydration and can be helpful for managing appetite, but should not be a replacement for whole food nutrition.

Water: The most important and truly zero-calorie beverage. Staying well-hydrated is crucial for all bodily functions and can help with feelings of fullness.
Unsweetened Tea: Green and black teas contain no calories and are rich in antioxidants, offering various health benefits.
Black Coffee: While coffee shops may load drinks with sugar and fat, plain black coffee is calorie-free.
Diet Sodas: These contain artificial sweeteners and typically have negligible calories, but offer no nutritional value. Some health organizations raise concerns about long-term use, so they should be consumed in moderation.

A Table of Low-Calorie, High-Volume Foods

Here is a list of extremely low-calorie vegetables and fruits, along with their approximate calorie count per 100 grams, highlighting their high water and fiber content.


Food	Calories (per 100g)	Primary Benefit	Water Content
Celery	14	High fiber, extremely low calories	95%
Cucumber	15	Hydrating, refreshing	95%
Spinach	23	Vitamins A, K, iron	91%
Broccoli	34	Vitamins C, K, fiber	89%
Lettuce (Romaine)	17	Hydration, vitamins	95%
Bell Peppers	31	Vitamin C, antioxidants	92%
Cabbage	25	Fiber, Vitamin C	92%
Zucchini	17	High water content, vitamins	95%
Cauliflower	25	Fiber, Vitamin C	92%
Watermelon	30	Hydration, vitamins A, C	91%
Grapefruit	42	Vitamin C, fiber	92%
Strawberries	32	Vitamin C, antioxidants	91%

How to Incorporate Low-Calorie Foods Into Your Diet

Instead of restricting your intake to only a few items, embrace a wide variety of low-calorie, nutrient-rich foods to build satisfying and healthy meals.

Fill Half Your Plate with Vegetables: Aim for a large portion of your meal to be composed of vegetables. This naturally reduces the overall calorie density of your plate while increasing volume and fiber.
Swap High-Calorie Ingredients: Replace higher-calorie items with low-calorie alternatives. Use spiralized zucchini instead of pasta, or cauliflower rice instead of white rice.
Boost Snacking: When a craving strikes, reach for low-calorie snacks like sliced cucumber, bell pepper strips, or a handful of berries. These satisfy hunger without derailing your calorie goals.
Bulk Up Soups and Salads: Add generous amounts of leafy greens, broccoli, and other vegetables to soups and salads. This creates a more filling meal with minimal added calories.
Don't Forget Healthy Fats and Protein: While focusing on low-calorie foods is beneficial, a balanced diet must include healthy fats and protein to support overall health and satiety. Foods like lean chicken, fish, eggs, and avocado add essential nutrients and help you stay full. For more authoritative guidance on integrating these components, consult resources like the Harvard Medical School's guide to healthy eating.

Potential Pitfalls of Focusing Only on "Zero-Calorie" Foods

Relying exclusively on extremely low-calorie foods, even the nutritious ones, can lead to serious health issues. This restrictive mindset is not a sustainable or healthy long-term solution.

Nutrient Deficiencies: Severely limiting your diet to a handful of items can result in a lack of essential macronutrients (protein, fat) and micronutrients, potentially causing fatigue, slowed metabolism, and other health problems.
Binge-Restrict Cycle: The psychological strain of eating a highly restrictive diet can lead to cycles of binge eating and restriction, which is detrimental to both physical and mental health.
Unhealthy Relationship with Food: Labeling foods as "good" or "bad" and obsessing over minimal calorie differences can foster an unhealthy and anxious relationship with eating.

Conclusion

The idea of a truly zero-calorie food, besides water, is a persistent myth. While the concept of "negative-calorie" foods is also not supported by science, focusing on low-calorie, nutrient-dense foods is an effective strategy for weight management and overall health. By incorporating high-volume, high-fiber, and high-water vegetables and fruits into a balanced diet that includes healthy fats and lean protein, you can feel satisfied and nourish your body properly. Sustainable and long-term health comes from a balanced and varied approach to eating, not from searching for a nonexistent, calorie-free magic bullet.

Frequently Asked Questions

Aside from water and unsweetened beverages like black coffee or tea, there are no foods that are genuinely zero calories. Packaged items labeled "zero calorie" are permitted to have up to 5 calories per serving, which food manufacturers can legally round down.

No, the concept of negative-calorie foods is a myth. While your body uses energy to digest food, the thermic effect of food is much less than the total calories the food provides. Even for low-calorie items like celery, you always end up with a net gain of calories.

Foods like celery and lettuce are high in water and fiber but very low in calories, making them less calorie-dense. They help fill you up and promote a feeling of fullness, which can lead to eating fewer calories overall.

High-fiber foods aid digestion, help stabilize blood sugar levels, and provide a feeling of satiety, or fullness, for a longer period. Since they take up more space in your stomach for fewer calories, they are beneficial for weight management.

Simply focusing on low-calorie foods is not a healthy or sustainable strategy. A balanced diet should also include lean protein and healthy fats for essential nutrients and sustained energy. Relying solely on low-calorie items can lead to nutrient deficiencies and an unhealthy relationship with food.

Excellent examples include leafy greens like spinach and kale, cruciferous vegetables such as broccoli and cauliflower, and high-water fruits like strawberries, grapefruit, and watermelon. These foods provide vitamins, minerals, and fiber with minimal calories.

Drinking cold water does cause a very small, temporary increase in your metabolic rate as your body works to warm it up. However, this effect is negligible and will not substantially increase the total calories your body burns, so it should not be considered a significant weight-loss strategy.