Matt Metzgar pointed this one out to me. Over at his blog he points to a piece of research:
looking at how calorie restriction affects muscle hypertrophy. Rats were subjected to muscle loading and then separated into calorie-restricted and non-calorie restricted groups. The surprising result is that the calorie restricted rats actually had greater muscle hypertrophy. The authors believe that this may be due to improved protein synthesis and oxidative capacity.
The abstract is here if you are interested.
The idea of eating less - which you can do through calorie restriction or intermittent fasting - to enhance your muscle growth is going against all the usual dogma. We have all read that you have to eat more calories to gain that muscle. Often quite absurd regimes of multiple feeds each day are recommended. (I'm not the only one to find these regimes hard to stick to!) I remember years ago thinking that I had to get up in the night to eat or drink a protein shake if I was serious about gaining muscle. I just got fat.
Thinking about it though, it does make sense. Fasting does promote GH release - Growth Hormone helps burn fat, build muscle and fasting triggers the “growth hormone response”, which prevents you from losing muscle while you fast. When your hungry the body switches to repair /growth mode to keep you alive.....
Art DeVany puts it like this:
Dr. De Vany: Our ancestors never ate three square meals a day and they surely didn't eat seven meals a day. They did forage over the land as they hunted and may have found wild plants and bugs to eat, but nothing like a protein bar (an entirely foreign substance to any human alive for most of our existence) or a high glycemic load supplement. Plants were only available seasonally to a hunter and hunting takes so much time and concentration of effort, there would have been little eating on the trail.
I calculate that they spent about one out of three days in fairly deep caloric stress. That is, they spent this time in negative caloric balance. This triggers growth hormone, which is protein conserving and activates the protective and rebuilding genes that express brain protective factors, heat shock proteins, and many repair and maintenance processes.
When you live in positive energy balance you 1) get fat eventually, and 2) your body expresses genes related to reproduction rather than maintenance. Growth factor expression is down-regulated during positive caloric balance.
Let’s face it, your genes don’t care about you. They just want to make sure you reproduce so they can live another day. When you're hungry and active, they switch to growth and repair to keep you alive for a while so you can reproduce later.
I randomly pick a day when "hunting is lean" (or so I tell myself) to eat sparingly, but I'm always active on such a day so my body knows it is to conserve its protein stores and use fat for energy (this is the hGH signal).
Brad Pillon's book Eat Stop Eat examines lots of research like this into IF.
Steve Mount is also keeping track of ongoing IF research here.