Digestion of cholesterol
The details of cholesterol digestion are extremely complex and unnecessary for the ensuing
discussion. As dietary cholesterol has no direct affect on ketosis, it will not be discussed further in
this chapter.
With regard to blood cholesterol levels, readers need to understand that the liver produces
more cholesterol (up to 2000 milligrams per day) than most individuals would ever consume, even
on a ketogenic diet. Additionally, when dietary cholesterol intake increases, the body’s synthesis
of cholesterol will typically go down. When dietary cholesterol intake goes down, the body’s
synthesis of cholesterol typically goes up. This supports the contention that dietary cholesterol
generally has little impact on blood cholesterol levels. The effects of the ketogenic diet on blood
cholesterol levels are discussed in chapter 7.
What tissues use fat?
As discussed in previous chapters, almost all tissues of the body can use FFA as a fuel
under proper conditions. From a purely energy perspective, there is no difference between dietary
fat and stored bodyfat. From that standpoint, there is no real requirement for dietary fat with
the exception of two essential fatty acids which must be consumed through the diet. Given the
same protein and carbohydrate intake, the more dietary fat which is ingested, the less bodyfat
which will be lost and vice versa.
How much fat per day?
As opposed to carbohydrate and protein, the body is able to store an almost unlimited
supply of calories as bodyfat. An average individual (150 lbs and 15% bodyfat or 22.5 lbs of fat)
carries almost 80,000 calories worth of stored fat in their adipose tissue. This is enough stored
energy to walk approximately 800 miles without exhausting fat stores. This, along with the fact
that there is only a small essential fatty acid requirement, raises the question of why a dieter
should eat any dietary fat on a ketogenic diet.
As discussed in the previous chapter, once ketosis is established, the majority of calories
burned by the body will come from fat breakdown. The remainder comes from the small
obligatory use of glucose by certain tissues, and the use of ketones. During total starvation, or
the protein sparing modified fast, up to 1800 calories (200 grams) or more of FFA may be burned
per day by an average sized person.
Although a high fat intake is necessary for epileptic children, this is because they must
maintain deep ketosis and weight loss is not desirable for developing children in most cases.
However, for epileptic children who are also obese, the ketogenic diet is used both as a treatment
for the epilepsy as well as to cause weight loss (12).
All of this data suggests that dietary fat is not a necessary part of a ketogenic diet from a
metabolic or adaptational standpoint as ketosis will readily develop without the consumption of
dietary fat (assuming protein and carbohydrate intake are not too high). From a strictly