If you reach day 5 and are really feeling beat up, low energy and bad, it’s acceptable to forego workout #3 and just continue on with the diet to close out Famine. Signs you’re “there” include loss of about 1 lb/day; a general feeling of weakness/malaise and a strong disinclination to train.
Famine is a good time to utilize some isolation movements for muscle groups or otherwise make use of Strive, Universal or Cybex machines that balance the weight for you. As a bonus, the central nervous system isn’t taxed like when using most free weight movements. Don’t get me wrong, I usually rail against machines but there’s a time and a place.
You may find nutrient intervention useful for the central nervous system during Famine in order to keep it fresh for the upcoming Feast rebound. Specifically, lecithin granules (2 tbs/day) can do wonders. These can be obtained very cheaply at a local supermarket or online. (The NOW foods brand makes a nice product for this purpose.) A couple of tablespoons in your yogurt, smoothie or with a plain drink mix otherwise goes a long way.
Supplementation in general should be very minimal during this time, except perhaps for detox teas and the like. It is a difficult but healthful and necessary exercise.
The combination of a caloric/protein deficit coupled with radically increasing physical demands sends a strong alarm signal to your brain. During this time your body will attempt to stop muscle loss by up-regulating every muscle building and preservation mechanism that it has. It’s mother nature’s way of keeping you alive. What you’ve just done is thus far what no prescription drug has been able to do; deactivate the ATP-dependent proteolytic pathway. You really are off-regulating all of the body’s muscle building mechanisms. It just doesn’t have the food yet or the time to do it.
At the end of day 5, you will be in a state where both catabolism and anabolism are very low. The beauty of this is that anabolism is now primed to be accelerated, while catabolism will lag and be kept to an absolute minimum (via increased insulin from overfeeding). The key is understanding how to enter into and amplify that state, where results pile up like a muscular landslide.