Nutrient density vs. calorie density is a fundamental nutrition concept. When you are making choices about what food to eat or buy at the grocery store, this is should be your guide. You want food that is going to fill you up, make you feel satisfied, and fuel your day, not leave you hungry, feeling deprived, exhausted, and still cause you to gain unwanted weight.
Let’s start out by defining our terms:
1) Nutrient: A substance that provides nourishment to the body. Nutrients include both Macronutrients (Carbohydrates, Proteins, and Lipids) and Micronutrients (Vitamins, Minerals, and Fiber).
2) Calorie: A unit of energy, similar to joules (1kcal = 4181J). Calories listed on food is how much potential energy is contained in that food, and not necessarily equal to the amount of calories that the body will absorb from the food. Also calories listed on food labels are actually kilocalories or kcals. It just makes it easier to make the labels and to understand, but its a good thing to know.
3) Density: In nutrition, density is nutrients or calories per unit of food (usually grams).
This might sound like it is about to get complicated, but it really isn’t. Think about it like this: Which is heavier, a pound of nails, or a pound of feathers? They are the same! They both weigh one pound, but there would be a lot more feathers than nails.
Now going back to nutrients and calories, we can think about this differently. Calorie density and nutrient density do not always go hand in hand. Foods that are very high in calories tend to be processed foods that are micronutrient poor, while whole foods are chocked full of nutrients and tend to have less calories.
Now obviously calories are important, and if we tried to avoid them that would be very bad for us. Eating too many isn’t ideal either because unused energy gets stored as fat, and can cause unwanted weight gain. But here is the really interesting thing: Nutrient-dense foods are good food, whole foods, and you do not have to worry about counting calories because it is hard to eat enough to go over your daily requirements. To be clear, I’m not saying that nutrient-dense foods are not substantive or will not fill you up.
For example: The average caloric requirements for an adult male are roughly 2,000kcal. Now this man could eat anything all day to meet that requirement and try to not go too far over. If he chooses to go by his local fast-food restaurant, he could get two burgers, a large order of fries, a large soda, and eat half a snickers bar. This would put his calories just over his 2,000kcal needs. This means that there is no room for any more drinks (besides water, black coffee, or plain tea) throughout the day, no room for any snacks or treats, anything to hold him over until tomorrow, or something that isn’t burger for breakfast. I don’t know about you but that sounds more like one big meal than a whole day’s worth of food to me. This means that this man will likely end up eating a lot more calories than he needs, or if he is trying to not go over his caloric requirements, he will likely feel hungry and deprived, and probably give up quickly.
On the other hand, if he eats a bowl of oatmeal with blueberries for breakfast, a hard-boiled egg for a snack, a salad of baby greens, cucumber, strawberries, walnuts, goat cheese, and vinaigrette, and a sandwich with turkey, lettuce, tomato, avocado, and mustard on whole wheat bread for lunch, a rice cake with peanut butter for an afternoon snack, whole grain pasta loaded with vegetables, chicken, marinara sauce, and parmesan cheese for dinner, a glass of wine, and still have calories left over.
That is a lot more food. If the man eats all of that he will feel full and satisfied, energized, and healthy, while if he eats the burgers, he will feel tired and still hungry. This will lead him to over-consume calories and he will keep gaining weight. If he just focuses on eating nutrient-dense foods, he does not need to worry about portion sizes or calorie counting.