Re: Fasting one day a week?

159682,

Before the body enters ketosis in the first 2 to 3 days of a water-only-fast, and the main fuel supply is provided by fatty-acids or ketones, the body will, in this interim period, be provided by its present fuel supply of glucose from the Liver, known as glycogen. It is only after these glycogen stores are depleted that ketosis begins in earnest.

Some glucose however, is still required by the body, so it makes the rest that it needs by catabolizing, or breaking down, the amino acids in muscle tissue, using them in the liver for gluconeogenesis, or the making of glucose. By the third day ketone production is sufficient to provide nearly all the energy the body needs, and the body's protein begins to be strongly conserved (protein-sparing). The body still needs a tiny amount of glucose for some functions, however, so a very small amount of protein, 18-24 grams, is still catabolized to supply it - from 1/2 to 1 ounce of muscle tissue per day. Over a 30 day Water Fast a person generally loses a maximum of 1-2 pounds of muscle mass (very little). This conservation of the body's protein is an evolutionary development that exists to protect muscle tissue and vital organs from damage during periods of insufficient food availability, otherwise the body would feed upon vital organs and you would die within a matter of days if not hours.

Chrisb1.