In addition to the seaweed and glycogen carbohydrates mentioned above, the Inuit can access many plant sources. The stomach contents of caribou contain a large quantity of partially digested lichens and plants, which the Inuit once considered a delicacy. They also harvested reindeer moss and other lichens directly. The extended daylight of the arctic summer led to a profusion of plant life, and they harvested plant parts including berries, roots and stems, as well as mushrooms. They preserved some gathered plant life to eat during winter, often by dipping it in seal fat.[71]

The fatty acids then flow into the bloodstream and are taken up by body tissues.  Once in the cells, the fatty acids are transported into the mitochondria of the cell to be metabolized carbon by carbon in a process called beta-oxidation. As glucose levels fall and fatty acid levels in the blood rise, the liver cells ramp up beta-oxidation which increases the amounts of a molecule called Acetyl-CoA. As the level of Acetyl-CoA rises, it is shunted to a process called ketogenesis. Ketogenesis generates a ketone body called acetoacetate first, and this ketone is then converted into the two other types of ketones: beta-hydroxybutyrate, and acetone.  Meanwhile, the glycerol part of the fat molecule gets converted into glucose in a process called gluconeogenesis, which means "make new sugar".
If you’re following the keto diet, you will need protein, but you should limit your intake to about 20 percent of your total daily calories. (1) This is important because when you consume more protein than you need, your body converts the excess protein into carbs through a process called gluconeogenesis. This process pushes your body out of ketosis.
"It’s not so easy to get an adult body into ketosis," says Teresa Fung, a professor of nutrition at Simmons College. "That’s why the keto diet is used as a treatment of epilepsy in children or infants—because it’s easier." Kids are growing rapidly, she explains, so their use of food as fuel is different from the way adults use it. Researchers aren’t exactly sure what those differences are, but Fung says it's so hard to get adults into deep ketosis (which is likely deeper than a dieter's target) that often nutritionists don't even attempt it as a therapy. It’s primarily kids who undergo the treatment today.
When you’re eating the foods that get you there (more on that in a minute), your body can enter a state of ketosis in one to three days, she adds. During the diet, the majority of calories you consume come from fat, with a little protein and very little carbohydrates. Ketosis also happens if you eat a very low-calorie diet — think doctor-supervised, only when medically recommended diets of 600 to 800 total calories.