I was just wondering if anybody knows how long it takes before you slow your metabolic rate into that bad starvation/survival mode that is often talked about? Is it a couple of hours? couple of days?

cheers

Great reference CVH, thanks!

To the OP, as supported by the link, the rate depends on how fat you are to begin with. As long as you're getting adequate protein, it's not as big a deal if you're carrying some extra energy stores.

Wow, thanks! that's great news and from a good source!

Mackross, metabolic rate actually increases for the first 36 hrs of a complete calorie fast, is about the same as pre fast for the next 12, and then starts to decrease after 48 hrs. Also your free amino acid pool will be exhausted after about 48hrs, and muscle will start to be catabolized for repair purposes. Note that all this happens completely independently of wether you have 'excess' bodyfat. Everybody has considerable visceral fat stores which are sufficient for at least a few days of energy requirements. Depending on how much and what type of exercise you are doing in that time.

Stuart.