Re: Fasting until all fat reserves are used up.

I would argue strongly against exercise while fasting.

The reduced dependence on glucose and therefore, the body's ability to spare muscle while powering itself primarily on fatty acids and ketones, requires a non-stressed states.

When you exercise so your body demands more energy than it can draw from its fat, it will draw from its muscle. This is both unhealthy since its muscle wasting, and it also makes the fast psychologically difficult since you will then be running on glucose.

Fasting should be a time to rest your body, not a time to punish your body. You should not be hungry at day 7 - you wouldn't be if you hadn't exercised.

In fact, weight training is probably the worst type of exercise you can possibly do on a fast because it disrupts muscle fibers (this is how muscle grows from weight training). When you're weight training, you are breaking down muscles to rebuild them with new protein, but when you're fasting you don't have any protein coming in. Of course you're hungry, you need protein. But don't think of eating any protein because that will screw up your electrolytes and could be very dangerous. If you do decide to break your fast do it on watery fruit or fresh squeezed fruit juice (which has potassium that you need while breaking a fast).


See this article on refeeding syndrome below for a reference to the fact that muscle sparing dependents on a non-stressed state and also why you shouldn't go straight into protein (it is also good for all fasters to know about refeeding syndrome, something you don't have to worry about if you break the fast the right way but that can be a real danger if you don't):

http://docs.google.com/viewer?a=v&q=cache:hC_42jiEa64J:citeseerx.ist.psu.edu/...
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