Nutrition

Caribou meat from hunt. Greenland
Because the climate of the Arctic is ill-suited for agriculture and lacks forageable plant matter for much of the year, the traditional Inuit diet is lower in carbohydrates and higher in fat and animal protein compared to the global average. When carbohydrate intake is inadequate for total energy requirements, protein is broken down in the liver through gluconeogenesis and utilized as an energy source. Inuit studied in the 1970s were found to have abnormally large livers, presumably to assist in this process. Their urine volumes were also high, a result of additional urea which the body uses to purge waste products from gluconeogenesis.[11] However, in multiple studies the traditional Inuit diet has not been shown to be a ketogenic diet.[12][13][14][15] Not only have multiple researchers been unable to detect any evidence of ketosis resulting from the traditional Inuit diet, but the ratios of fatty-acid to glucose were observed to be well below the generally accepted level of ketogenesis.[12][13][14][15]

Inuit actually consume more carbohydrates than most nutritionists have assumed.[16] Because some of the meat the Inuit eat is raw and fresh, or freshly frozen, they can obtain more carbohydrates from their meat, as dietary glycogen, than Westerners can.[16][17] The Inuit practice of preserving a whole seal or bird carcass under an intact whole skin with a thick layer of blubber also permits some proteins to ferment, or hydrolyze, into carbohydrates.[16] Furthermore, the blubber, organs, muscle and skin of the marine mammals that Inuit eat have significant glycogen stores, which assist those animals when oxygen is depleted on prolonged dives.[18][19][20] For instance, when blubber is analyzed by direct carbohydrate measurements, it has been shown to contain as much as 8—30% carbohydrates.[19] While postmortem glycogen levels are often depleted through the onset of rigor mortis, marine mammals have a much delayed onset of rigor mortis, even in warm conditions, presumably due to the high content of oxymyoglobin in the muscle that may permit aerobic metabolism to continue slowly for some time after the death of the animal.[19][21] Additionally, in cold conditions, glycogen's depletion is halted at -18 °C (-0.4 °F) and lower temperatures in comminuted meat.[22][23]

Traditional Inuit diets derive approximately 50% of their calories from fat, 30–35% from protein and 15–20% of their calories from carbohydrates, largely in the form of glycogen from the raw meat they consumed.[24][25] This high fat content provides valuable energy and prevents protein poisoning, which historically was sometimes a problem in late winter when game animals grew lean through winter starvation. It has been suggested that because the fats of the Inuit's wild-caught game are largely monounsaturated and rich in omega-3 fatty acids, the diet does not pose the same health risks as a typical Western high-fat diet.[26] However, actual evidence has shown that Inuit have a similar prevalence of coronary artery disease as non-Inuit populations and they have excessive mortality due to cerebrovascular strokes, with twice the risk to that of the North American population.[27][28] Indeed, the cardiovascular risk of this diet is so severe that the addition of a more standard American diet has reduced the incidence of mortality in the Inuit population.[29] Furthermore, fish oil supplement studies have failed to support claims of preventing heart attacks or strokes.[30][31][32]

Vitamins and minerals which are typically derived from plant sources are nonetheless present in most Inuit diets. Vitamins A and D are present in the oils and livers of cold-water fishes and mammals. Vitamin C is obtained through sources such as caribou liver, kelp, whale skin, and seal brain; because these foods are typically eaten raw or frozen, the vitamin C they contain, which would be destroyed by cooking, is instead preserved.[33]