Many of us know about the importance of eating a balanced diet with fruit, vegetables, nuts and seeds as well as small portions of meat and fish, but it can still be hard to know which foods will provide the essential nutrients our bodies need.

Now scientists have cut out some of the guess work by ranking the most nutritious foods.

Researchers studied more than 1,000 raw foods and gave each one a score based on their nutritional value. The top ten are listed below:

*Almonds: Rich in mono-unsaturated fatty acids, these nuts contain fibre, protein, magnesium and vitamin E. Almonds also promote cardiovascular health and may help with diabetes.

*Cherimoya: This fruit is fleshy and sweet with a white pulp. Rich in vitamins A, C, B1, B2 and potassium. The skin and its crushed seeds are toxic.

*Ocean Perch: A deep-water fish sometimes called rockfish, red perch or red bream. High in protein, low in saturated fats. 100 grams of Ocean perch fish contains no carbohydrates and is a good source of protein.

*Flatfish: Sole and flounder species. Generally free from mercury and a good source of the essential nutrient vitamin B1. All flatfish are less than 100 calories per three ounce cooked serving, are a good source of protein and have less than two grams of fat.

*Chia seeds: Tiny black seeds that contain high amounts of dietary fibre, protein, a-linolenic acid, phenolic acid and vitamins. A good source of omega-3 fatty acids, fibre, antioxidants, iron, and calcium.

*Pumpkin seeds: Including the seeds of other squashes. One of the richest plant-based sources of iron and manganese, they also contain a wide variety of nutrients including copper, protein and zinc.

*Swiss chard: A very rare dietary source of betalains, phytochemicals thought to have antioxidant and other health properties. Swiss chard is also an excellent source of vitamins K, A, and C, as well as a good source of magnesium, potassium, iron, and dietary fibre.

*Pork fat: A good source of B vitamins and minerals and an excellent source thiamin, zinc, vitamin B12, vitamin B6, niacin, phosphorus, and iron. Pork fat is more unsaturated and healthier than lamb or beef fat.

*Beet greens: The leaves of beetroot vegetables. High in calcium, iron and also a great source of fibre. Packed with antioxidants, as well as magnesium, potassium, copper, and manganese, and low in cholesterol.

*Snapper: A family of mainly marine fish, with red snapper the best known. These fish are rich in selenium, vitamin A, potassium and omega-3 fatty acids but low in calories and a lean source of protein.

So now you know which foods have the most nutritious value, maybe you can add some of them to your shopping list the next time you make a trip to the supermarket.

Sources: Plos.org / BBC