The myelin sheath is consist of a cell called the glial
cell. The glial cell is the one responsible for providing assistance in neurons
as well as insulation of which will be in between of them. This type of cell is
usually seen in the CNS and it has different types.
Calories in and of themselves aren't a reliable way of describing energy density in food. It doesn't reflect what actually happens in your body (look up bomb-calorimeter for how people figure out calorie content in foods). So based on this, the question is a bit of a non-sequitur. But if you disregard that and go with a regular answer, it really depends on what kind of calories you're ingesting because foods get digested in a function of different amounts of time. Carbohydrates will get digested and converted into glucose almost immediately - being very close to 100% energy efficiency. Fats are the slowest as your body needs to produce bile in order to digest it - not enough bile = undigested fat = unused calories. Proteins are turned into either amino acids (not an energy source per se) or converted into glucose like carbs but instead through gluconeogenesis which is a less efficient form of glucose conversion than carbohydrates (since your liver/kidneys need to produce the enzymes to convert it). The efficiency of protein is likely in the range of 50-60% calories. This is just the tip of the iceberg though - your metabolism also plays a part as to how much and when these calories are either used, stored, and excreted by your body. Ever got the meat sweats? That's your body burning excess energy through thermogenesis when you eat too much protein. So it really depends why you're asking because the answer will differ for each scenario.
Answer:
it is over a long period of time
Explanation: