To my mind, ketogenic eating is any regimen which results in nutritional ketosis. Nutritional ketosis is a metabolic pathway, not a list of foods or an approved menu. A ketogenic 'diet' can range from low-carb junk food to high fat carnivore and anywhere in between.
EDIT: minor correction to the article - to my knowledge glucagon is a hormone made by the pancreatic alpha cells. In turn stimulating the liver into reconverting glycogen back into glucose to be sent out into the bloodstream. Glucagon isn't released by the liver?