What Is the Lowest Calorie Food
Cucumber, celery and lettuce are usually named as the lowest calorie foods, each containing under 20 calories per cup thanks to their high water content. But what is the lowest calorie food really comes down to how you define “lowest”: is it a single ingredient, a food group, or something you eat as part of a meal? This guide breaks it down properly, using verified nutrition data, so you get a straight answer rather than a vague list.
If you’re trying to lose weight, manage a health condition, or simply eat smarter, knowing which foods give you the most volume for the fewest calories is genuinely useful. Below, we’ll look at the actual Low Calorie Snacks foods by category, explain the official definitions behind the “low calorie” label, and clear up a persistent myth that even trips up experienced dieters.
The Lowest Calorie Foods at a Glance
For a fast, snippet-ready answer: cucumber (8 calories per half-cup), celery (14–18 calories per cup), lettuce (5 calories per cup), and clear broth (under 15 calories per cup) rank among the lowest calorie foods available. These foods are low in calories mainly because they’re over 90% water, with very little fat, sugar or starch to add energy density.
No solid food has zero calories. Even the lightest vegetables carry a handful of calories per serving. The idea of a true “zero calorie” or “negative calorie” food is a myth, which we’ll explain properly further down.
How “Lowest Calorie” Is Actually Defined
Before ranking foods, it helps to know how nutrition authorities define the term, since this is where a lot of online lists get sloppy.
According to guidance referenced by Harvard Health Publishing, the FDA considers a food “low-calorie” if it contains 40 calories or less per serving, and a meal or main dish qualifies as low-calorie if it has 120 calories or less per 100 grams. This is a legal labelling threshold, not a ranking of the single lowest calorie food in existence.
For the purposes of this guide, “lowest calorie food” means the foods with the smallest number of calories per typical serving size, based on standard nutrition databases such as the USDA FoodData Central.
Lowest Calorie Vegetables
Vegetables dominate any genuine low-calorie food list, largely because of their water and fibre content.
- Cucumber around 8 calories per half-cup (mostly water, very filling for the calorie cost)
- Celery around 14 to 18 calories per cup, high in fibre and a classic low-calorie snack
- Lettuce (iceberg or romaine) around 5 to 8 calories per cup
- Chard and other leafy greens roughly 7 calories per cup, raw
- Asparagus around 27 calories per cup, with useful amounts of vitamin K and folate
- Mushrooms (raw, white button) low calorie and a good meat substitute for bulk in meals
- Beetroot around 59 calories per cup, still low but denser than leafy greens
These are what nutritionists call high-volume, low-calorie foods. You can eat a generous portion without a big calorie cost, which helps with satiety when you’re managing your intake.
Lowest Calorie Fruits
Fruit tends to carry more natural sugar than vegetables, so the calorie counts sit a little higher, but several are still very low for their volume.
- Strawberries: under 50 calories per cup
- Watermelon: around 46 calories per 150-gram serving, over 90% water
- Clementines: around 35 calories per fruit
- Berries generally (blueberries, raspberries): among the lowest calorie fruits available per serving
Fruit also brings fibre and vitamin C, so it’s rarely worth avoiding purely on calorie grounds.
Lowest Calorie Drinks
Drinks are often overlooked in “lowest calorie food” discussions, yet they’re an easy way to cut calories without changing your meals.
- Water: 0 calories
- Black coffee and plain tea: effectively 0 calories without milk or sugar
- Green tea: 0 calories, and some research links it to modest fat-loss support
- Club soda and sparkling water: 0 calories
- Clear vegetable or bone broth: very low calorie and useful as a base for filling soups
Lowest Calorie Proteins
Protein foods generally carry more calories than vegetables, but some options are notably lighter than others.
- Cod and other white fish lean and low in calories compared with fattier fish
- Egg whites far lower in calories than whole eggs, while still protein-rich
- Low-fat cottage cheese (1%) a low-calorie option that still delivers protein
Is There Such a Thing as a “Zero Calorie” or “Negative Calorie” Food?
Not really, and this is one of the most misunderstood parts of the topic.
The theory behind so-called negative-calorie foods is that chewing and digesting them burns more energy than the food actually provides, creating a calorie deficit just by eating. It sounds appealing, but the research does not support it. <cite index=”12-1″>Every one of these foods contains calories, and there is no evidence that digesting them uses more energy than they provide</cite>. Even <cite index=”12-1″>chewing gum has been shown to raise energy use by only around 11 calories an hour</cite>, which is far too small to offset a food’s actual calorie content.
Regulators do allow a “zero calorie” label in limited cases. Foods can legally be marketed as zero calorie if a single serving contains fewer than 5 calories, though the serving size used for that claim can be deceptively small.
The practical takeaway: focus on genuinely low-calorie, nutrient-dense foods rather than chasing the idea of foods that supposedly cancel themselves out. Extremely restrictive eating built around this myth can also lead to nutritional shortfalls, so balance still matters more than any single “lowest calorie” ingredient.
How to Use Low-Calorie Foods Without Losing Nutrition
Cutting calories only works well long-term if you’re still getting enough nutrients. A few practical tips:
- Pair low-calorie vegetables with a lean protein source so meals stay filling, not just light
- Use broth-based soups as a starter to reduce overall portion sizes without leaving you hungry
- Swap calorie-dense sauces and dressings for lemon juice, vinegar or herbs
- Choose whole fruit over fruit juice, since juice strips out the fibre that helps you feel full
- Avoid dropping below your body’s minimum energy needs, since under-eating can cause fatigue, nutrient deficiencies and muscle loss over time
Most adults aiming for gradual, sustainable weight loss are generally advised to stay within a moderate calorie deficit rather than eating as few calories as physically possible. If you have a specific health condition or weight goal, a registered dietitian can help set a safe target for you.
Final Thoughts
So, what is the lowest calorie food? Among whole foods, water-rich vegetables like cucumber, celery and lettuce come closest to the bottom of the scale, sitting well under 20 calories per serving. Zero-calorie drinks such as water, black coffee and plain tea sit even lower, at effectively no calories at all. What matters more than chasing the single lowest number, though, is building meals around these foods in a way that still meets your body’s nutritional needs. A sensible mix of low-calorie vegetables, lean protein and whole fruit will do far more for your health than any one “magic” low-calorie ingredient ever could.
Frequently Asked Questions
1. What is the lowest calorie food you can eat?
Cucumber and lettuce are among the lowest calorie whole foods, at roughly 5 to 8 calories per cup, largely because they’re made up mostly of water.
2. Is there a food with zero calories?
No solid food has true zero calories, though items like water, black coffee and plain tea are effectively calorie-free. Foods can be labelled “zero calorie” if a serving contains fewer than 5 calories.
3. Do negative calorie foods really exist?
No. This is a popular myth. Every food provides some energy, and there’s no reliable evidence that digesting foods like celery or cucumber burns more calories than they contain.
4. What is the lowest calorie fruit?
Watermelon and strawberries rank among the lowest calorie fruits, at under 50 calories per serving, thanks to their high water content.
5. Are low-calorie foods always healthy?
Not automatically. A food can be low in calories but still low in nutrients. It’s better to choose low-calorie foods that are also nutrient-dense, such as vegetables, lean proteins and whole fruit, rather than ultra-processed “diet” products.
