Answer:
Macronutrients are defined as chemical substances required in large amounts by the body for survival. The three macro-nutrients are protein, carbohydrates, and fats. The amounts of different macro-nutrients a person needs as well as the ratio of nutrients to each other varies by age, lifestyle (sedentary, active, or very active), gender, health status, and health goals.
Types of Macronutrients
Calories per Macronutrient
Carbohydrates
4 calories per gram of carbohydrates
Protein
4 calories per gram of protein
Fat
9 calories per gram of fat.
Role of macro-nutrients in our diet:
(i) Carbohydrates
(a) Carbohydrates include starches, starches, sugars, and fiber.
(b) Body uses carbohydrates to fuel the body.
(c) Carbohydrates come in two forms plex and simple. Simple carbohydrates include sugars like table sugar and high fructose corn syrup, which have one or two sugar molecules (mono-disaccharides). Honey and maple syrup contain simple sugars, as well as other nutrients. Complex carbohydrates are long chains of simple sugars stuck together, also called polysaccharide. They can be either starches or fiber (cellulose from plants). Foods like whole wheat pasta and white potatoes contain complex carbohydrates.
(d) Adults should get between \[45-65%\] their daily calories from carbohydrates.
(e) Humans don't produce the enzymes necessary to digest fiber.
(f) Sources of Carbohydrates: The best carbohydrates are micronutrients dense whole foods that contain sugar or starches along with fiber. Breads, cereals, pasta, rice, beans and peas, and starchy vegetables such as potatoes, green peas, corn honey, candy, soft drinks, and frosting or icing are sources of carbohydrates.
(ii) Proteins
(a) Protein is the building block responsible for the growth and maintenance of eyes, skin, hair, nails, organs, and muscle tissue.
(b) During digestion, protein is broken down into smaller chains called polypeptides and individual units called amino acids for absorption. Of the 22 amino acids that make up proteins, nine are called 'essential' amino acids, which means that our bodies do not produce them and must get them from food. These include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Histidine is unique in that it is only required during infacy.
(c) Protein embeds themselves in cells to regulate what goes in and out. They even envelop and transport some molecules to other locations in the body.
(d) Enzymes that catalyze the various chemical reactions in the body are made of folded chains of amino acids.
(e) The body creates hormones like leptin, immune proteins like interferon and antibodies using amino acids.
(f) Sources of Protein
Nuts, seeds, grains and vegetables, are called incomplete proteins because they do not contain all nine essential amino acids together, as meats, eggs and dairy products do. One won't develop a protein deficiency on a plant-based diet as long as one eats a balanced died that combines plant foods with different amino acids.
(iii) Fat
(a) Fat is the densest source of energy in the diet.
(b) In the body, fats make up cell membranes, steroids, cholesterol, and \[60\,%\] of the brain.
(c) Fats support the absorption of fat soluble vitamins, cushion organs, and acts as largest form of energy storage.
(d) Fats should account for \[25-35%\] of the daily calories.
(e) Dietary fats include saturated and un-saturated fats.
(f) Saturated fats tend to come from animal sources, while most plant fats are unsaturated. There are also important essential fatty acids, namely omega-3 and omega-6. As with essential amino acids, the term essential means that the human body cannot produce it and we must get these from our diet. There is also an unnatural type of fat known as trans fats. Trans fats are often described as poison. Trans fat raise 'bad' LDL cholesterol and have no place in a healthy diet.
(g) Sources of Fat
Nuts, seeds, avocados, olives, coconut, dark chocolate, grape seed oil, sunflower oil, walnut oil, sesame oil, coconut oils, meat are good source of fat.
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