This list is a categorization of the most common food components based on their macronutrients. Macronutrients can refer to the chemical substances that humans consume in the largest quantities (See Nutrient)
Macronutrients that provide energyEdit
There are three principal classes of macronutrients: carbohydrate, protein, and fat. Macronutrients are defined as a class of chemical compounds which humans consume in relatively large quantities compared to vitamins and minerals, and which provide humans with energy. Fat has a food energy content of 38 kilojoules per gram (9 kilocalories per gram) and proteins and carbohydrates 17 kJ/g (4 kcal/g).
Water makes up a large proportion of the total mass ingested as part of a normal diet, but it does not provide any nutritional value. Ethanol provides calories, but there is no requirement for ethanol as an essential nutrient.
- Amylose (a major component of starch)
Essential and non-essential amino acids
- Aspartic acid (aspartate)
- Glutamic acid (glutamate)
- Acetic acid (C2)
- Propionic acid (C3)
- Butyric acid (C4)
- Valeric acid (C5)
- Caproic acid (C6)
- Caprylic acid (C8)
- Capric acid (C10)
- Lauric acid (C12)
- Myristic acid (C14)
- Pentadecanoic acid (C15)
- Palmitic acid (C16)
- Margaric acid (C17)
- Stearic acid (C18)
- Arachidic acid (C20)
- Behenic acid (C22)
- Lignoceric acid (C24)
- Cerotic acid (C26)
Monounsaturated (i.e., semi-stable) fatty acidsEdit
Polyunsaturated (i.e., unstable) fatty acidsEdit
- Linoleic acid (LA) - an essential fatty acid
- α-Linolenic acid (ALA) - an essential fatty acid
- Stearidonic acid (SDA)
- Gamma-Linolenic acid (GLA)
- Arachidonic acid (AA)
- Eicosatetraenoic acid (ETA)
- Timnodonic acid (EPA)
- Clupanodonic acid (DPA)
- Cervonic acid (DHA)
Essential fatty acidsEdit
- Ethanol: The U.S. Department of Agriculture uses a figure of 6.93 kilocalories (29.0 kJ) per gram of alcohol (5.47 kcal or 22.9 kJ per ml) for calculating food energy. For distilled spirits, a standard serving in the United States is 44 ml (1.5 US fl oz), which at 40% ethanol (80 proof), would be 14 grams and 98 calories.
Macronutrients that do not provide energyEdit
Water is essential for life. It provides the medium in which all metabolic processes proceed. It is necessary for the absorption of macronutrients and micronutrients, but it provides no nutritional energy.
Dietary fiber from fruits, vegetables and grain foods. Insoluble dietary fiber is not absorbed in the human digestive tract, but is important in maintaining the bulk of a bowel movement to avoid constipation. Soluble fiber can be metabolized by bacteria residing in the large intestine. Soluble fiber is marketed as serving a prebiotic function with claims for promoting "healthy" intestinal bacteria. Bacterial metabolism of soluble fiber also produces short-chain fatty acids like butyric acid, which may be absorbed into intestinal cells as a source of food energy.
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