The Best Low-Calorie Foods That Keep You Full

Why some foods fill you up for fewer calories

Energy density is the number of calories in a given weight of food, usually expressed as calories per gram. Water adds weight and volume without calories, fiber adds bulk and slows digestion, and protein tends to be more filling than the same calories from carbohydrate or fat. Fat, at 9 calories per gram, raises energy density quickly.

A widely used way to group foods, used in CDC materials on weight management, is: very low energy density (under 0.6 calories per gram), low (0.6–1.5), medium (1.5–4) and high (4–9). Most vegetables and fruits fall in the very low group. Chips, cookies, nuts, butter and oils fall in the high group.

Studies suggest people tend to eat a fairly consistent amount of food by weight from meal to meal. Shifting more of that weight toward low-energy-dense foods is one of the most practical ways to eat fewer calories without feeling like you are eating less.

Non-starchy vegetables

Non-starchy vegetables are the lowest-calorie foods you can eat in large portions. Approximate values per 100 g raw, based on USDA FoodData Central: cucumber about 15 calories, iceberg lettuce about 14, celery about 15, zucchini about 17, tomato about 18, mushrooms about 22, spinach about 23, cauliflower about 25, red bell pepper about 31 and broccoli about 34.

For perspective, a large bowl containing 300 g of mixed salad vegetables usually comes to well under 100 calories before dressing. The dressing is often where the calories are: one tablespoon of olive oil is about 120 calories, so measuring it, or using a vinegar-based dressing, makes a big difference.

Roasting, steaming and stir-frying all work well. If you roast vegetables with oil, measure the oil rather than pouring freely, since it can easily add more calories than the vegetables themselves.

Fruits

Most whole fruits are very low or low in energy density and provide fiber, potassium and vitamin C. Per 100 g: watermelon about 30 calories, strawberries about 32, cantaloupe about 34, orange about 47, apple about 52 and blueberries about 57.

Water content is what keeps these numbers low, which is why dried fruit is so different. Grapes have about 69 calories per 100 g, while raisins have about 299. About 100 calories of grapes is roughly a cup, but the same 100 calories of raisins is only about 3 tablespoons. Fruit juice also lacks the fiber of whole fruit and is easier to drink in large amounts.

Lean proteins

Protein foods help you stay full and protect muscle while you eat less. Several are low in calories per gram: egg whites have about 52 calories and 11 g of protein per 100 g, plain nonfat Greek yogurt about 59 calories and 10 g of protein, and cooked cod about 105 calories and 23 g of protein.

Chicken breast, at about 165 calories per 100 g cooked, is higher in calories than these but is mostly protein, which makes it a filling choice. Low-fat cottage cheese, shrimp, canned tuna in water and tofu are other useful options. Breading, frying and creamy sauces can easily double the calories of a lean protein, so the cooking method matters.

Filling starches and whole grains

You do not need to avoid starches to eat fewer calories. Several are moderate in energy density and quite filling. Boiled potatoes have about 86 calories per 100 g, oatmeal cooked with water about 71, and cooked lentils about 116 along with about 8 g of fiber and 9 g of protein.

Air-popped popcorn is a whole grain with about 31 calories per cup, so a 3-cup bowl is under 100 calories. Toppings such as butter or oil change that quickly. Broth-based vegetable soups are another useful option, since they combine water and vegetables in a warm, satisfying form.

Worked example: two 400-calorie plates

Compare two portions with about the same calories. Plate one: 150 g of roasted chicken breast (about 248 calories), 200 g of steamed broccoli (about 70 calories) and 100 g of boiled potatoes (about 86 calories). That is about 404 calories and 450 g of food, with roughly 50 g of protein and plenty of fiber.

Plate two: about 75 g of potato chips, which also comes to roughly 400 calories because chips have around 530 calories per 100 g. That is one-sixth the weight of the first plate, with little protein and little fiber. The first plate is far more likely to keep you full until the next meal.

You do not have to give up energy-dense foods. A practical approach is to fill about half your plate with vegetables or fruit, a quarter with a lean protein and a quarter with a starch, then add fats in measured amounts.

Watch for low-calorie labels

Packaged foods marketed as light, diet or low-fat are not always low in calories per serving, and some replace fat with sugar or refined starch. In the US, low calorie is a regulated term that generally means 40 calories or fewer per reference serving, but other wording on the front of a package is less precise.

The nutrition facts panel is the most reliable guide. Check the serving size, the calories, and the protein and fiber per serving. Scanning a barcode in the Goby AI app is a quick way to compare similar products side by side.

Keep your diet balanced

Low-calorie foods are tools, not a complete diet. You still need enough protein, healthy fats from foods such as olive oil, nuts, seeds and fish, and a variety of foods to cover vitamins and minerals. Eating only very low-calorie foods can leave you short on energy and nutrients. Very large jumps in fiber can also cause bloating, so if you are adding a lot more vegetables, beans or whole grains, increase them gradually and drink enough water.

If you are pregnant, have diabetes or another medical condition, or have a history of disordered eating, talk to your doctor or a registered dietitian before cutting calories significantly.