Let me first say that I'm not into fitness in the athletic or 
body-building sense. My only interest in fitness is for maintenance of 
current health, mobility, and strength as it relates to being able to 
putter in my garage/workshop, or wrestle with household tasks - and win. 
I'm also a big fan of longevity but am not convinced of the benefits of 
an exercise program to that end.   I am 62 years old and have fairly 
severe lung disease (about 51% of normal function due to diffuse scar 
tissue) so my exercise can not be intense. Despite all of that, my 
experience may be relevant to the present discussion. When I excluded 
gluten, almost 20 years ago, I experienced significant reductions in 
post-exercise muscle pain and stiffness.

Having read (in Lyle Macdonald's book) that a ketogenic diet improved 
the lung function of  healthy young adults by about 10%, I tried the 
diet.  The first time, I experienced about a 30% improvement in lung 
function as measured by peak flow expiration rate.  I have since had 
several stints of following the diet, but the allure of carbohydrates 
usually proves just too much for me and I falter. However, during those 
times of ketosis, my lung power increases. Post-exercise muscle pain and 
stiffness also disappears. It is difficult to tell whether the many 
other benefits of this diet ensue from my improved breathing or more 
directly from the diet but I experience a variety of benefits.

I can only guess that part of your (Jim, Wally, and Keith) improved 
fitness is driven by your diet. For myself, I can be very confident that 
is the underlying cause of my improvements since that is about the only 
factor that has changed. I don't do any exercise other than walking and 
puttering in my garage.

Best Wishes,
Ron