Calorie density is used to describe the number of calories in a given volume or weight of food.
Understanding how it works can help you lose weight and improve your diet (1).
This can have many health benefits, including an increased nutrient intake and weight loss.
This article explains everything you need to know about calorie density.
Calorie density is a measure of the calorie content of food relative to its weight or volume.
It is also called energy density, and is usually measured as calories per 100 grams (3.5 ounces) of food.
An easier way to make sense of this is to imagine a full plate of food. The fewer calories the plate contains, the lower the calorie density of the meal is.
A vegetable that contains 30 calories per 100 grams has a low calorie density, while chocolate that contains 550 calories per 100 grams has a very high calorie density.
This diagram shows the concept very well: Although calorie density may be less well known than other weight management methods, such as calorie counting, choosing foods based on this measure may actually be simpler and more effective (7).
For example, basing your diet on low-calorie-dense foods tends to reduce your food options in a positive manner because it limits you to predominantly healthy and nutrient-rich whole foods.
It can quickly clean up your diet, eliminating most calorie-dense, processed foods that are generally unhealthy and easy to overeat.
Summary: Calorie density describes the number of calories per weight or volume of food. It's a very simple, effective method to improve your diet.
Several studies have shown that individuals who consume low-calorie-dense diets also consume fewer total calories per day. This is also linked with a lower body weight, body mass index (BMI) and waist circumference (10, 11).
Calorie density also has important effects on hunger.
In contrast, many high-calorie-dense foods are highly processed and extremely palatable. As you may know, they are very easy to overeat.
In one study, participants ate 56% more calories when provided with a high-energy-dense meal, compared to a low-energy-dense meal (2).
Another study compared calorie intake for high- and low-calorie-density meals that were matched for palatability and macronutrients.
Participants given the high-calorie-dense meal consumed an average of 425 more calories than when they were given the low-calorie-dense meal (3).
Summary: Research has linked people's intake of high-calorie-dense foods with weight gain and obesity. Those who eat more low-calorie-dense foods tend to eat fewer calories and have a lower body weight.
A low-calorie-dense diet is perfect for weight loss for several reasons.
For starters, it focuses on natural, whole foods and limits your intake of processed foods.
This is normally combined with an increased intake of protein, vegetables and fruit.
A low-calorie-dense diet can help with hunger, since your stomach senses the volume of food you have consumed in a meal.
A low-calorie-dense meal also fills your plate. This helps make your meal last longer and forces you to chew more, further increasing your feelings of fullness (13).
In one study, participants lost an average of 17 lbs (7.7 kg) after they switched their high-calorie-dense fats to low-calorie-dense fruits and vegetables for one year (4).
Finally, results from a five-year observational study found that men and women who consumed lower-calorie-dense diets had significantly lower measurements of waist circumference and BMI (10).
Summary: Research has shown that a low-calorie-dense diet can be a great method to lose weight and improve your general eating habits.
Quite simply, a low-calorie-dense diet forces you to overhaul your diet and make many positive changes.
All of these changes benefit your long-term health.
A low-calorie-dense diet includes:
- Less processed food: Your intake of processed, unhealthy food will be reduced.
- More healthy food: You will eat more low-calorie, highly nutritious foods.
- More lean proteins: These can help with weight loss and have several other benefits (16).
- More nutrients: A low-calorie-dense diet encourages you to consume more micronutrient- and antioxidant-rich fruits and vegetables.
- Reduced calorie intake: Reducing your calorie intake and losing weight is one of the best ways to improve your health if you're overweight (18, 19).
- A well-balanced, sustainable diet: This way of eating teaches you to focus on healthier, low-calorie foods while not forcing you to totally eliminate other foods or food groups forever.
Summary: Along with helping you lose weight, a low-calorie-dense diet is also linked with many other aspects of a healthy lifestyle.
Apart from healthy high-fat foods, such as nuts and olive oil, most natural foods have a very low calorie density. These include:
- Vegetables: Vegetables have a very low calorie density. Most green vegetables have the lowest out of all foods. This is because they are primarily made up of water, fiber and a very small amount of carbs.
- Meat and fish: Lean proteins like chicken, white fish and turkey have a low calorie density, yet fattier meats and fish have moderate-to-high calorie density.
- Fruits: These have a low calorie density because of their high fiber and water content. Berries and other watery fruits tend to have the lowest density.
- Milk and yogurt: Reduced-fat milk and yogurts with no added sugar also have a low calorie density and provide a good source of protein.
- Eggs: Whole eggs are a protein-packed superfood with a low calorie density, especially when combined with vegetables into meals such as omelets.
- Starchy carbs: Some natural starchy carbs like potatoes, legumes and other root vegetables can have a low-to-moderate calorie density. This is especially true once they're cooked, since they fill with water.
- Sugar-free drinks: Beverages such as water, coffee, tea and other sugar-free drinks technically have a low calorie density and can help keep you full.
Summary: Most unprocessed and natural foods have a low calorie density. This is particularly true of vegetables, fruits, lean meats and fish and eggs.
If you want to try this approach and base your food selection on calorie density, you will need to limit your intake of foods with high calorie density.
Here are a few key foods you'll want to limit:
- Candy and chips: Candy and chips tend to be high in sugar and fat, making them very calorie-dense and very easy to overeat.
- Pastries and cakes: Like candy, pastries and cakes are very calorie-dense and easy to overeat.
- Fast foods: These are some of the most calorie-dense food on the planet. Studies show an average fast food meal contains around twice the calories of a normal, healthy meal (5).
- Oils: While certain oils are healthy, such as coconut and olive oil, they still have a very high calorie density. Avoid all processed vegetable oils and consume healthy oils in moderation.
- High-fat dairy: Although they may have health benefits, foods like butter, cream and cheese have very high calorie densities. Consume them in moderation.
- Fatty meats: Some fatty meats have a very high energy density. This includes bacon, sausages, lamb, fatty beef cuts and several others.
- Nuts: Like other healthy fat sources, nuts are very calorie-dense. While they do have many health benefits, they are easy to overeat. Try measuring out your portions before you eat them.
- High-fat condiments: Some sauces and sides, such as mayonnaise, pesto and ranch dressing, are very high in calories and should mostly be avoided.
- Sugary drinks: Soda, juice, commercial high-sugar smoothies and milkshakes are high in empty calories and should be avoided as much as possible.
Summary: If you are trying to lose weight, limit your intake of most foods with high calorie density. Some natural high-fat foods are healthy and can be consumed in small quantities.
Out of the hundreds of diets around, an eating plan based on foods with a low calorie density is probably one of the most sensible and effective. It's also very easy to understand and implement.
Unlike diets that focus on excluding food groups, a low-calorie-dense diet allows you to consume all foods while simply shifting your focus towards healthy, whole foods.
Plus, you'll also have less hunger and be able to consume a large amount of healthy, whole foods.
By basing 90% of your intake on foods with a low calorie density, you can easily reduce calorie intake and lose weight with little effort.