Whole, natural foods — generally defined as those with minimal to no processing — are the foundation for good nutrition and in turn good health. We hear it all the time. But why?

According to experts, whole natural foods are healthiest because they provide essential nutrients that are more easily absorbed and used by the body. Whole foods provide nutrients, fiber and antioxidants and have fewer trans fats, added sugars, preservatives and sodium than processed foods.

A balanced diet may vary among individuals, but should include a balance of protein, carbohydrates and fat. People can track their micronutrient intake to understand what their bodies are getting. That will also help them know if they are deficient in certain nutrients. People need nine essential amino acids for cells to function properly: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Those can be found in both animal and plant foods.

Protein

Protein should make up 10% to 35% of daily calories, and contrary to popular belief, most people meet or exceed the daily recommendation, according to the Mayo Clinic. Healthy proteins include:

• Soy, nuts, seeds, beans and lentils

• Lean meats like chicken or turkey

• Seafood

• Egg whites

• Low-fat dairy

Carbs

Carbohydrates are vital as they provide the body with its main source of energy, protect against disease and help control weight, according to the Mayo Clinic. The Dietary Guidelines for Americans recommend that carbs make up 45% to 65% of daily calories. Healthy carbs include:

• Whole fiber-rich fruits and vegetables

• Whole grains, which also contain important B vitamins

• Beans, peas and lentils, which are low in fat and high in folate, potassium, iron and magnesium. They can also be a health substitute for meat.

Fat

Experts recommend that fats make up 20% to 35% of daily calories, in general. Fats are essential in that they provide energy and help in absorbing vitamins. But it’s important to choose fats wisely. Saturated and trans fat should be limited as they can raise cholesterol and the risk of heart attack and stroke. Unsaturated fat, on the other hand, can improve cholesterol levels and reduce that risk. Omega-3 fatty acids, in particular, have been shown to boost heart health.

Monounsaturated fat can be found in olive, canola, peanut and sunflower oils, avocados, peanut butter and many nuts, as well as in chicken, pork and beef. Polyunsaturated fats can be found in nuts, seeds and include Omega-3 fatty acids found in fatty fish like salmon, herring and sardines.

Meat consumption may also vary among individuals, and dietitians say a general rule is that a serving should be no larger than the size of one’s palm. Red meat should be limited in order to cut back on total saturated and trans fats. Poultry, fish and plant-based proteins can be eaten in its place.

Treats

So what about the guilty pleasures? The things we know we should not be eating, like treats with excessive amounts of sugar and processed foods? Well, there is a reason we call it “junk” food. Processed food typically contains a lot of sugar, refined carbohydrates, unhealthy fats, too much salt and more.

Those who eat an otherwise healthy diet might be able to get away with small amounts of processed foods, though again, the definition of small varies from person to person, dietitians say. And if the treats cannot be eaten in moderation, individuals should avoid them.