The fat fast is metabolic starvation at its finest. You eat 900 calories from fat and a few from protein. If you eat macadamia nuts, as most do, you eat very little sodium. What you experience is the flushing of water from your fat cells - the water that replaced the fat you already lost. Losing a few lbs on the fat fast is normal - it's mostly water. If you continue on too long you start to lose muscle. Muscle is easier for your body to break down than fat.

The fat fast was designed to jump start ketosis. It is supposed to be used by people who are stalled or on a plateau. A stall, btw, is six (6) weeks with no scale or inches lost. Once in ketosis you are burning fat, and should have succeeded in breaking your stall / plateau. You very often gain back most if not all of the scale weight you lost - but this isnt the point of the Fat fast. The point is to get you into Ketosis and burning fat if you are stalled and / or very resistant.

Exercising during a fat fast? I've tried a fat fast - I don't think you'd have the energy to exercise so the point may just be moote.

Nat