On Mon, 10 Dec 2001 12:49:40 +0100, Paul Sand <[log in to unmask]> wrote:

>When I'm trying to eat more fat than let's say 65-70 % of total calories
>intake I get tired and irritated and experience headaches and low energy
>levels. ...

People describe onset of ketosis like this.
You are deprived of carbohydrates as brain and nerve fuel,
and your symptoms are what an underfueled brain feels like.
Brain needs approx 500 kcal carbohydrate per day.

It should go away after some days (at most 4), onstantly on this low
carb diet.
After that brain makes enzymes which enable it to live for 50% on fat.

The rest (some 250kcal) must come from carbohydrate, no other way.
But these carbohydrate may come from degraded protein.
250kcal require some 100g protein (500g meat).
In addition to the ordinary protein reguirements of some 40g/day.

Amadeus