Macronutrients: Carbohydrates, Fats and Proteins
Macronutrients are nutrientsthe body needs in large amounts, because they provide the body with energy.
Carbohydrates
- Role in the Body Carbohydrates, also known as starches and sugars, arethe body's main energy source. Your body uses carbohydrates to make glucose, which is our main fuel. Either glucose is used immediately or it is stored it in the liver and muscles as glycogen for later use.
- Recommended Allowance In general, 45 – 65% of your daily calories should come from carbohydrates. Carbs have 4 calories/gram. Based on a 2,000 calorie/day diet, this amounts to 900 – 1300 calories per day, or about 225 – 325 grams. Determine your daily caloric intake.
- Food SourcesCarbs arefound in all plant foods (grains, vegetables, fruit, legumes and nuts), dairy and foods containing added sugars. Healthier foods higher in carbohydrates include ones that provide dietary fiber and whole grains as well as those without added sugars.
- Complex Carbohydrates provide a slower and more sustained release of energy than simple carbohydrates. This contributes to long-term good health, appetite control and sustained energy levels. Complex carbohydrates include legumes, grains and starchy vegetables, such as potatoes, peas and corn.
- Simple Carbohydrates The more refined the carbohydrate, the faster the glucose is released into your blood, which can cause peaks and drops in your blood sugar level and less stable energy levels in the body. Simple carbohydrates are found mainly in fruits and milk, as well as in foods made with sugar, such as candy and other sweets.
Proteins
- Role in the Body Proteins are part of every cell, tissue and organ in our bodies. They are constantly being broken down and replaced. The protein in the foods we eat is digested into amino acids that are later used to replace these proteins in our bodies. They are involved in metabolic, transport, and hormone systems and they make up enzymes that regulate metabolism. Proteins defend the body against disease through immune function.
- Recommended Allowance In general, it's recommended that 10-35% of your daily calories come from protein. Protein has 4 calories/gram. Based on a 2,000 calorie/day diet, this amounts to 200 – 700 calories per day, or about 50 -175 grams a day. The USDA Dietary Guidelines 2010 recommends a daily allowance of 0.36 grams of protein per pound of body weight. Rather than simply focusing on your protein needs, choose an overall healthy eating plan that provides the protein you need as well as other nutrients.
- Food sources Protein is found in meat, poultry, fish, legumes (dry beans and peas), tofu and other soy products, eggs, nuts, seeds, milk and other dairy products, grains and some fruits and vegetables.
Most adults in the US get more than enough protein to meet their needs. It's rare for someone who is healthy and eating a varied diet to not get enough protein. Emphasize plant sources of protein, such as beans, lentils, soy products and unsalted nuts. Include seafood twice a week. Meat, poultry and dairy products should be lean or low fat.
Fats
- Role in the Body Fats provide energy during endurance exercise, in between meals, and in times of starvation. They constitute an essential component of cell membranes, insulate and act as a shock absorber for bones and organs. Fats are not necessarily bad for you, but you only need a small amount.
- Recommended Allowance Only 20-35% of total daily calories should come from fat; less than 10% should come from saturated fat. Fats have 9 calories per gram. Based on a 2,000 calorie/day diet, this amounts to about 400 -700 calories a day, or about 44 – 78 grams of total fat. Saturated fats (those that are solid at room temperature: butter, shortening, etc.) should comprise no more than 10% of your fat intake.
- Food Sources Unsaturated or“good” fats includevegetable oils, salad dressings, avocados, ground flax seeds, nuts, seeds andfatty fish (salmon, sardines, mackerel). Saturated or “bad” fats are found in high-fat cuts of beef and pork, full fat dairy products, butter and varioussnack foods (cookies, pastries, donuts). Trans fats (the really bad fats!) are found in some margarines, deep-fried foods, snack foods (chips, crackers, pastries, donuts) and anything with hydrogenated ingredients.
Micronutrients: Vitamins and Minerals
Water-Soluble Vitamins
Water-soluble vitamins travel freely through the body and excess amounts are usually excreted by the kidneys. The body needs water-soluble vitamins in frequent, small doses. These vitamins are not as likely as fat-soluble vitamins to reach toxic levels.
| Nutrient | Function | Sources |
|---|---|---|
| Thiamine (vitamin B1) | Part of an enzyme needed for energy metabolism; important to nerve function | All nutritious food contain moderate amounts, especially pork, whole-grain or enriched breads and cereals, legumes, nuts and seeds |
| Riboflavin (vitamin B2) | Part of an enzyme needed for energy metabolism; important for normal vision and skin health | Milk and milk products; leafy green vegetables; whole-grain or enriched breads and cereals |
| Niacin (vitamin B3) | Part of an enzyme needed for energy metabolism; important for nervous system, digestive system, and skin health | Meat, poultry, fish, whole-grain or enriched breads and cereals, vegetables (especially mushrooms, asparagus, and leafy green vegetables), peanut butter |
| Pyridoxine (vitamin B6) | Part of an enzyme needed for protein metabolism; helps make red blood cells | Meat, fish, poultry, vegetables, fruits |
| Folic acid | Part of an enzyme needed for making DNA and new cells, especially red blood cells | Leafy green vegetables, legumes, seeds, orange juice, and liver; now added to most refined grains |
| Cobalamin (vitamin B12) | Part of an enzyme needed for making new cells; important to nerve function | Meat, poultry, fish, seafood, eggs, dairy; not found in plant foods |
| Ascorbic acid (vitamin C) | Antioxidant; part of an enzyme needed for protein metabolism; important for immune system health; aids in iron absorption | Found only in fruits and vegetables, especially citrus fruits, vegetables in the cabbage family, cantaloupe, strawberries, peppers, tomatoes, potatoes, lettuce, papayas, mangoes, kiwifruit |
Fat-soluble vitamins
Fat-soluble vitamins are stored in the body's cells and are not excreted as easily as water-soluble vitamins. They do not need to be consumed as often as water-soluble vitamins, although adequate amounts are needed. Too much of a fat-soluble vitamin can become toxic. A balanced diet usually provides enough fat-soluble vitamins.
| Nutrient | Function | Sources |
|---|---|---|
| Vitamin A or beta-carotene (converted by the body to vitamin A) | Needed for vision, healthy skin and mucous membranes, bone and tooth growth, immune system health | Animal sources (retinol): fortified milk, cheese, cream, butter, fortified margarine, eggs, liver Plant sources (beta-carotene): leafy, dark green vegetables; dark orange fruits (apricots, cantaloupe) and vegetables (carrots, winter squash, sweet potatoes, pumpkin) |
| Vitamin D | Needed for proper absorption of calcium; stored in bones | Egg yolks, liver, fatty fish, fortified milk, fortified margarine and sunlight (converted to vitamin D by the skin) |
| Vitamin E | Antioxidant; protects cell walls | Polyunsaturated plant oils (soybean, corn, cottonseed, safflower), leafy green vegetables, wheat germ, whole-grain products, liver; egg yolks, nuts and seeds |
| Vitamin K | Needed for proper blood clotting | Leafy green vegetables and vegetables in the cabbage family, milk, also produced by bacteria in the intestinal tract |
Minerals
| Nutrient | Function | Sources |
|---|---|---|
| Calcium | Helps build and maintain strong bones and teeth, helps blood clot, helps nerves and muscles function | Milk and milk products, broccoli, dark leafy greens, fortified products such as orange juice, soy milk and tofu |
| Potassium | Aids in nervous system and muscle function, helps maintain healthy balance of water in blood and body tissues | Broccoli, bananas, potatoes with skin, prune juice, orange juice, leafy green vegetables, raisins, tomatoes |
| Sodium | Regulates water balance, stimulates nerves | Table salt, processed meats, canned foods, poultry, eggs, milk |
| Iron | Needed to transport oxygen to all parts of the body via red blood cells | Leafy green vegetables, beans, shellfish, red meat, eggs, poultry, soy, some fortified foods |
| Zinc | Vital to many internal processes, supports immune function, reproduction and the nervous system | Red meat, fortified cereals, oysters, almonds, peanuts, chickpeas, soy foods, dairy products |
See Also
Micronutrients | Soil Fertility