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Low calorie foods are foods that supply few calories for their weight or serving size, usually because they are mostly water, contain fiber, or are lean sources of protein with little fat. Watery vegetables such as cucumber, lettuce and zucchini sit at the bottom of the scale, followed by melons and berries, then lean fish, egg whites and nonfat dairy, then beans and potatoes. This guide gives a low calorie foods list built from USDA data, explains the idea of energy density, looks at what studies say about filling low calorie foods, and shows how FDA rules shape the word “low calorie” on a package. It describes nutrition only; it does not set calorie goals for anyone.
Peptide Labs does not sell foods on this list. This article is general nutrition information, not medical advice.
Key Takeaways
- Water has no calories and fat has the most per gram, so watery foods are low in calories and fatty foods are high.
- USDA data put cucumber, lettuce, zucchini and tomatoes at under 0.2 calories per gram.
- Lean protein foods such as cod, shrimp and nonfat Greek yogurt are low in calories for the protein they supply.
- Studies by Barbara Rolls and colleagues found that water-rich, high-fiber foods eaten first increased fullness at a meal.
- On a package, "low calorie" has a legal meaning: no more than 40 calories per reference amount under FDA rules.
What makes a food low calorie?
The key idea is energy density, the number of calories in each gram of food. Penn State researcher Barbara Rolls, who has studied it for decades, summarized in a 2017 review that energy density depends mostly on two things: water, which adds weight with no calories, and fat, which supplies about 9 calories per gram. Carbohydrate and protein supply about 4. So a food that is 95% water, like cucumber, has very few calories per bite, while dry or oily foods, like crackers, nuts and oils, pack many calories into a small amount.
Fiber helps too. It adds bulk and contributes few usable calories, which is why beans and whole fruit are more filling than their calorie counts suggest. Protein matters for a different reason: in some studies a higher-protein snack increased fullness more than a lower-protein one with the same calories. Our guides to fiber-rich foods and protein-rich foods cover those nutrients in depth, and the opposite end of the scale is in our high calorie foods guide.
Low calorie foods list with USDA values
The table lists common foods from the USDA FoodData Central SR Legacy database with the FDC ID for each entry. Values are per typical serving, with the Daily Value percentage for fiber (28 grams) and protein (50 grams), plus calories per gram so foods of different serving sizes can be compared. Foods are grouped, not ranked.
| Food and serving (USDA FDC ID) | Calories | Water | Fiber (% DV) | Protein (% DV) | Calories per gram |
|---|---|---|---|---|---|
| Cucumber with peel, 1/2 cup slices (168409) | 8 | 95% | 0.3 g (1%) | 0.3 g (1%) | 0.15 |
| Romaine lettuce, 1 cup shredded (169247) | 8 | 95% | 1.0 g (4%) | 0.6 g (1%) | 0.17 |
| Zucchini, raw, 1 cup chopped (169291) | 21 | 95% | 1.2 g (4%) | 1.5 g (3%) | 0.17 |
| Cherry tomatoes, 1 cup (170457) | 27 | 95% | 1.8 g (6%) | 1.3 g (3%) | 0.18 |
| White mushrooms, 1 cup slices (169251) | 15 | 92% | 0.7 g (2%) | 2.2 g (4%) | 0.22 |
| Broccoli, raw, 1 cup chopped (170379) | 31 | 89% | 2.4 g (8%) | 2.6 g (5%) | 0.34 |
| Watermelon, 1 cup diced (167765) | 46 | 91% | 0.6 g (2%) | 0.9 g (2%) | 0.30 |
| Strawberries, 1 cup whole (167762) | 46 | 91% | 2.9 g (10%) | 1.0 g (2%) | 0.32 |
| Cantaloupe, 1 cup cubes (169092) | 54 | 90% | 1.4 g (5%) | 1.3 g (3%) | 0.34 |
| Apple with skin, 1 medium (171688) | 95 | 86% | 4.4 g (16%) | 0.5 g (1%) | 0.52 |
| Egg white, from 1 large egg (172183) | 17 | 88% | 0 g (0%) | 3.6 g (7%) | 0.52 |
| Cod, cooked, 3 oz (171956) | 89 | 76% | 0 g (0%) | 19.4 g (39%) | 1.05 |
| Shrimp, cooked, 3 oz (175180) | 84 | 74% | Not listed | 20.4 g (41%) | 0.99 |
| Greek yogurt, plain nonfat, 1 container (170894) | 100 | 85% | 0 g (0%) | 17.3 g (35%) | 0.59 |
| Cottage cheese 1%, 4 oz (173417) | 81 | 82% | 0 g (0%) | 14.0 g (28%) | 0.72 |
| Potato, boiled in skin, 1 potato (170438) | 118 | 77% | 2.4 g (9%) | 2.5 g (5%) | 0.87 |
| Lentils, boiled, 1/2 cup (172421) | 115 | 70% | 7.8 g (28%) | 8.9 g (18%) | 1.16 |
| Black beans, boiled, 1/2 cup (173735) | 114 | 66% | 7.5 g (27%) | 7.6 g (15%) | 1.32 |
| Popcorn, air-popped, 3 cups (167959) | 93 | 3% | 3.5 g (12%) | 3.1 g (6%) | 3.87 |
| Vegetable broth, 1 cup (171583) | 11 | 98% | 0 g (0%) | 0.5 g (1%) | 0.05 |
Vegetables
Non-starchy vegetables are the lowest-calorie group in USDA data. Cucumber, romaine, zucchini and tomatoes are about 95% water, and broccoli and mushrooms add a little more protein. Leafy greens belong here as well; see our leafy greens guide, plus our cucumber and zucchini guides. Cooking with a lot of oil, butter or cheese changes the numbers more than the vegetable itself.
Fruits
Melons and berries are about 90% water, and a medium apple supplies 16% of the fiber Daily Value. Whole fruit and fruit juice behave differently: juice keeps the sugar but loses most of the fiber and bulk. Our strawberries and apple guides give full nutrient profiles.
Lean protein foods
Cod, shrimp, egg whites, nonfat Greek yogurt and 1% cottage cheese are low in calories for the protein they supply. Breading, frying and creamy sauces add calories quickly, so preparation matters as much as the food. Our shrimp guide covers sodium and allergy facts.
Beans, potatoes and popcorn
Beans and boiled potatoes have more calories per gram than vegetables, but they bring fiber, protein or potassium and are filling for their calories. Air-popped popcorn is the odd one out: dry, so high in calories per gram, yet three cups weigh only 24 grams and take up a lot of space. Our lentils and black beans guides go further.
Broth-based soups
A cup of vegetable broth has about 11 calories in USDA data. Broth-based soups with vegetables and beans are mostly water, which is why they appear in the energy-density studies below. Canned broths can be high in sodium, so check the label.
Filling low calorie foods: water, fiber and protein
Calories alone do not tell you how satisfying a food will be. Research on fullness points to the same three features over and over, though most studies are short and done in lab settings:
- Water-rich first courses: Rolls’s 2017 review describes studies in which a large first course of a low-energy-dense food, such as a broth-based soup, salad or fruit, increased fullness and reduced total calories eaten at that meal. When the energy density of meals was lowered, adults and children ate fewer calories without being told to.
- Whole fruit over juice: in a 2009 study of 58 adults, eating a whole apple before lunch reduced total calories at the meal by 15% compared with no apple, and it increased fullness more than applesauce or apple juice with the same calories. The study was funded by the NIH.
- Protein: in a 2013 study of 15 healthy women, a higher-protein yogurt snack led to less hunger, more fullness and a later request for dinner than a lower-protein snack with the same calories. The sample was small.
- Volume: a 2012 study of 35 adults found less hunger and more satisfaction after 100 calories of popcorn than after 150 calories of potato chips. It was funded by a popcorn maker, which is worth knowing when reading the result.
Feeling full is shaped by hormones as well as food volume; our hunger hormones guide explains ghrelin, leptin and GLP-1. For snack-sized ideas, see our guide to low-calorie snacking.
Low calorie does not always mean nutritious
A food can be low in calories and offer little else, and a calorie-dense food can be very nutritious. Diet sodas and many “light” packaged foods are low in calories but supply few nutrients, while nuts, olive oil and avocado are high in calories and supply mostly unsaturated fats. The idea that some foods take more energy to digest than they contain is a myth our negative calorie foods guide examines. Fat-free or reduced-calorie packaged foods sometimes add sugar to keep the taste; our sibling guide to foods high in sugar shows where it hides. If you want to understand how calories in and calories out are measured, see what a calorie deficit is.
How FDA calorie wording works on labels
Packaged foods can only use calorie claims that meet FDA definitions in 21 CFR 101.60:
- “Calorie free” or “zero calories”: fewer than 5 calories per reference amount and per labeled serving. Under FDA label rules, amounts under 5 calories may be shown as zero.
- “Low calorie”: no more than 40 calories per reference amount; for foods with small reference amounts, also per 50 grams.
- Naturally low foods: a food that is low in calories by nature, such as celery, must word the claim so it does not suggest it is special compared with other foods of its type.
A claim describes one serving, so the Nutrition Facts panel and serving size still matter. Oils and sprays labeled zero calories, for example, rely on a very small serving.
Who should get personal advice
- Eating disorders: if tracking calories or food lists causes distress, talk with a clinician; the National Eating Disorders Association lists support options.
- Small appetite or GLP-1 medicines: people eating very little need enough protein and nutrients in each bite; our GLP-1 diet guide covers that balance.
- Children, pregnancy, older adults and athletes: energy needs differ widely, so a registered dietitian is the right source for individual advice.
Frequently Asked Questions
What are low calorie foods?
Foods that supply few calories for their weight, usually because they are mostly water, contain fiber or are lean protein with little fat. Watery vegetables and fruits are the lowest in USDA data.
What is on a low calorie foods list?
Cucumber, lettuce, zucchini, tomatoes, mushrooms, broccoli, melons, berries, apples, egg whites, cod, shrimp, nonfat Greek yogurt, cottage cheese, beans, boiled potatoes, air-popped popcorn and broth.
Which low calorie foods are most filling?
Studies point to foods high in water, fiber or protein, such as broth-based soup, salad, whole fruit, beans and Greek yogurt. Most studies are short and small.
What does low calorie mean on a food label?
Under FDA rules, no more than 40 calories per reference amount. Calorie free means fewer than 5 calories per serving.
Are low calorie foods always healthy?
No. Some low-calorie packaged foods supply few nutrients or contain added sugar, while some calorie-dense foods such as nuts are nutritious.
Is popcorn a low calorie food?
Air-popped popcorn is dry and has many calories per gram, but it is light and bulky, so three cups have about 93 calories in USDA data. Butter and oil add more.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Foods High in Sugar: USDA Values, Added Sugars and Hidden Sources, Low Calorie Snacks: USDA Calories per Serving and 100-Calorie Portions, Negative Calorie Foods: The Myth, the Math and the Low-Calorie Foods That Help, Low Calorie Fruits: USDA Calories per Cup, Ranked.