As the name implies, macronutrients are types of nutrients that are required in “macro” or large amounts.¹ They play essential roles in the body to provide energy, synthesize molecules, produce hormones, and regulate various metabolic pathways. Carbohydrates, protein, and fat make up the three major types of dietary macronutrients.²

CARBOHYDRATES 

Carbohydrates encompass a broad category of foods and can be subcategorized into simple and complex carbohydrates.^3,4 Simple carbohydrates, or more commonly known as sugars, are easily used as energy and can cause sudden rises in blood glucose levels and stimulate insulin secretion.² Complex carbohydrates, on the other hand, take longer to be digested and must first be broken down into sugars.² They have a less drastic and immediate effect on blood glucose levels. 

Carbohydrates are broken down into glucose in our digestive system for immediate use as energy or stored in muscle tissue and the liver for future use.² They also play a role in lipid metabolism and fermentation, affect blood glucose and insulin levels, and their intake has been of interest in weight, diabetes, aging, heart health, and gut health -related research.³ The 2020-2025 Dietary Guidelines for Americans (DGA) recommends 45-65% of daily calories or 130 g per day to come from carbohydrates.⁵

Sources of Carbohydrates:^2,6 

·      Milk

·      Fruits

·      Sugar-sweetened beverages (eg, soda, sports drinks, energy drinks, fruit drinks)

·      Desserts

·      Sweet snacks (eg, candies)

·      Breakfast cereals

·      Grains and grain products (eg, wheat, pasta, bread, rice, oats)

·      Starchy vegetables (eg, potatoes, corn, lotus root, lima beans, plantains, water chestnuts, yam)

·      Beans (eg, lentils, peas, chickpeas)

PROTEIN

Proteins are biomolecules made up of amino acids and play an important role in building muscles, tissues, hormones, and enzymes in the body.^7,8 Of the common 20 amino acids, eight must be consumed in our diets for proper human growth, metabolism, and tissue repair and maintenance. The Recommended Dietary Allowance for protein in healthy individuals is 0.8 g of protein/kg of body weight.⁸ The 2020-2025 Dietary Guidelines for Americans (DGA) recommends a daily intake of 5.5 ounces of protein for a 2,000 kcal-diet.⁵ Protein subgroup weekly recommendations are as follows: 26 oz/week of meats, poultry, and eggs; 8 oz/week of seafood; 5 oz/week of nuts, seeds, and soy products.

Sources of Proteins:⁵

·      Meats

·      Poultry

·      Eggs

·      Seafood

·      Beans, nuts, seeds, and soy products (eg, tofu)

FAT 

Fats are an essential part of the human diet.⁹ Fatty acids are make up a crucial component of the cell and are precursors to important biomolecules.¹⁰ Additionally, they provide a rich source of energy and promote the absorption of other nutrients and fat-soluble vitamins. Dietary fats are categorized into four types based on the number and configuration of double bonds in the fatty acid chain: monounsaturated, polyunsaturated, saturated, and trans fats.⁹  

Monounsaturated fats contain a single double bond and are considered to be a healthy type of fat.⁹ Polyunsaturated fats such as Omega-3 and Omega-6 fatty acids contain more than one double bond and are also known as a healthy fat. Various trials have shown that increased intake of monounsaturated and polyunsaturated fats may be associated with lowered risk of cardiovascular diseases as well as other chronic conditions (eg, inflammatory-related diseases, type 2 diabetes, dementia, cancer).^9,11–14 On the other hand, saturated fats contain no double bonds and are linked to negative effects on cardiovascular health such as increased low-density lipoprotein cholesterol levels and an increased risk of coronary heart disease.⁹ The 2020-2025 DGA recommends limiting the intake of saturated fats to <10% of daily calories by replacing them with unsaturated fats, especially polyunsaturated fats.⁵ Trans fats are artificially manufactured via the hydrogenation process so that liquid forms of fat can be converted to semi-solid or solid forms to be incorporated into commercial foods with increased shelf life.⁹ Studies have shown that increased intake of trans fats is associated with negative changes to lipid profiles. The 2020-2025 DGA recommends minimal consumption of trans fat.⁵

Sources of Fats:^5,9,12,15

·      Canola oil, olive oil, safflower oil, peanut oil, flaxseed oil, soybean oil, coconut oil, palm oil

·      Nuts and seeds (eg, almonds, walnuts, peanuts, cashews, hazelnuts, pecans, sunflower seeds)

·      Avocado

·      Oily fish (eg, tuna, salmon, sardines)

·      Eggs

·      High-fat meat

·      Full-fat dairy products (eg, whole milk, full-fat cheese, ice cream)

·      Butter