Water Fasting & Exercise: which does the body burn first, muscle or protein?

I've read several posts in this form that exercising during a Water Fast is not good nor recommended since the body will strip muscles of protein to convert into glucose for energy.

Yet in other places on the internet I've read that when the body needs energy, after exhausting all quick energy, it then turns to stored fat and not muscle. The body does discriminate between energy sources burning stored fat first then muscle protein second.

I've also learned that athletes who participate in lengthy sporting activities (marathon's, swimming across a channel, etc.) will intentionally gain weight prior to their event (adding fat). They do this to give their body extra energy reserves to sustain them until the end of their event.

After the body expends all quick energy sources the body then turns to stored fat as the next available energy source. Seasoned athletes have learned to cope with the body's transition period from burning quick energy to burning fat. Most of us regular folks who aren't as active will experience this transition occur during day 1 and day 5 of our fast. That's when we feel the lull and loss energy sometimes nearing the point of just wanting to sleep all day.

I'd like to know if anyone else has any other feedback as to which the body burns first: body fat or muscle?

I look forward to all replies.

Chris Tweet