Many people feel that eating less is starving, but in fact this understanding is a bit narrow. Food calories vary, so how to choose low-calorie food? For the concept of “density”, I believe that we are not unfamiliar, but when it comes to “nutrient density”, I believe that many people are not clear. It refers to the concentration of a nutrient per unit of energy in food. Nutrient density is a more important reference data than nutrient content (concentration of a nutrient per 100 grams of food) to avoid excess energy when supplementing certain vitamins or minerals in the diet. Unfortunately, there is no authoritative data found for ranking all foods by nutrient density, so it is not certain that the foods mentioned in the article are the most nutrient-dense foods. However, it is worth affirming that the foods mentioned in the article are foods with high nutrient density and should be eaten often. Salmon: To get enough omega-3 fatty acids, it is best to eat deep-sea fatty fish such as salmon. The fatty acid is good for the heart, and also enhances memory and improves mood. Deep-sea fatty fish is also a good source of high-quality protein, vitamin D, vitamin E and other nutrients. Kale: 100 grams of kale contains only 22 kcal, but is rich in beta carotene, vitamin K, vitamin B6, potassium, calcium and magnesium, and many other nutrients. Lee Wai-ming pointed out that most leafy greens are low in calories, a category of food with high nutrient density. Shellfish: These include clams and oysters, among others. Clams are one of the best sources of vitamin B12, and are also rich in high-quality protein, many B vitamins, potassium and iron. Oysters are rich in nutrients such as zinc, copper, vitamin B12 and vitamin D. Potatoes: Compared to staple foods such as rice, potatoes are rich in many micronutrients such as potassium, magnesium, iron, copper and manganese, as well as a large amount of vitamin C and most B vitamins, making them a high nutrient density staple food. Blueberries: Although their vitamin and micronutrient content is not as high as that of vegetables, the antioxidant content is extremely outstanding. Phytochemicals such as anthocyanins in blueberries help enhance blood vessel elasticity, protect the lining of arterial blood vessels, promote the regeneration of retinal cells in the retina, and improve vision. Li Huiming said that in addition to blueberries, purple foods such as purple kale and grapes are also rich in anthocyanins. Dark chocolate: It is rich in nutrients such as dietary fiber, iron, magnesium and manganese. The most prominent feature of dark chocolate is that it is rich in antioxidants. Regular consumption of dark chocolate can help lower “bad” cholesterol levels and improve brain function. Generally speaking, the nutritional density of foods in the diet can usually be effectively increased by choosing foods with lower fat or sugar content, such as fruits instead of sweets. Conversely, adding large amounts of oil, sugar and other ingredients to food can significantly reduce the nutrient density of food.