Ketone bodies provide energy for body's needs when there is a total food restriction, carbohydrate restriction, and/or long enough physical effort.

In beginning of ketosis, ketones provide up to 75% of total energy requirement, including energy required by brain. Most dieticians say that carbohydrate is only fuel for nerve cells but it is not true. It's a preferred fuel, yes, but not only one. If there are little or no carbohydrates, all tissues of body including brain tissue can adapt to using alternative fuel.

As body undergoes process of adaptation to ketosis, amount of carbohydrates required reduces. This explains why brain fog and muscle weakness can occur in beginning of ketosis but becomes very rare after a week or two. In fact, it's true that a diet is considered low carb if it contains less than 100 carb grams a day, but it's only true until adaptation to ketosis develops. After it is completed, carb requirement is around 40 grams. None of non-clinical low carb diets takes this fact into account.

After 1-2 weeks, as process of adaptation to ketosis develops and tissues no longer rely on carbohydrates for fuel, they send less signals requesting beta-cells in pancreas to release insulin -- resulting in decrease of insulin concentration in blood.

Low insulin level frees its antagonistic fat burning hormones from suppression resulting in increased levels of glucagon, growth hormone, catecholamines, and glucocorticoid.

Glucagon is most important insulin antagonist; it's up to glucagon to control fatty acids' release from fat stores to be burnt for fuel. So, as glucagon release increases, insulin goes down. It is thought that to initiate ketosis, carbohydrate intake should be reduced to less than 30g/day.

However, there's a most important condition grossly overlooked by authors of low carb diets. Any food is either ketogenic or glucogenic depending on it influence on competition between glucagon and insulin. To make ketosis possible, a meal should contain at least 1.5 g of fat per every 1 g of protein plus carbohydrate combined.

Only that or higher of a ratio makes food ketogenic enough to allow eating without portion and calorie control. Foods with ketogenic indexes below 1 promote insulin release and are essentially anti-ketogenic. Foods with indexes between 1 and 1.5, though not anti-ketogenic, require calorie control since their ketogenic properties are not strong enough to significantly suppress carbohydrate metabolic pathway and mobilize body fat for fuel thus causing healthy hunger decrease.

But your finicky cell membrane does not allow whole glutathione molecules to cross over directly into your cellular spaces. And every time a molecule of glutathione neutralizes a destructive free-radical or toxin, it fatally binds with undesirable element and is washed out with them in bile or urine.

So how do you replenish your stores and get your daily fix of glutathione? Simple. You manufacture it in your cellular factory, from its raw materials - glycine, glutamate and cysteine.

If your human eats a diet high in fresh fruits and vegetables and freshly prepared meats, you should get be getting enough glutamate and glycine. But cystine comes mostly from eggs, milk and cheese. And when eggs, milk and cheese are cooked or processed, composition of Cystine is changed to Cysteine (small difference in spelling, but BIG difference in action). While still a valuable protein, it can no longer feed your glutathione levels.

If you can get a sufficient supply of cysteine (which determines rate at which you can make glutathione), your arsenal is well- stocked. If not, you and your human are at a strategic disadvantage in battle of "Cell v/s Free-radical Destroyers."

As a normal, healthy cell, increasing your glutathione levels could help you and your human maintain that strategic advantage in battle against free-radicals. If you're not really in your prime, boosting your levels could tip scales in your favor, and help you fight cellular damage that causes disease and aging.