Like I enjoy saying "drive a car, burn money and get fat...ride a 
  bike, burn fat and save money."

  So I had an image of what our fellow cyclists would look like when 
  my husband, son and I arrived in Castagneto Carducci for a cycling 
  vacation. They would look like Mr. Hampsten, who at age 45 remains 
  boyishly thin and agile, bouncing with energy.

  I was wrong. For the most part, our group consisted of ordinary-
  looking, mostly middle-age men and a few middle-age women.

  These were serious cyclists. One of them was Bob Eastaugh, a 63-
  year-old justice on the Alaska Supreme Court who said he rode mostly
  to stay in shape for his true passion, downhill ski racing.

  And our trip was challenging. The longest hill was 15 miles, the 
  steepest had a 15 percent grade, the longest one-day ride was 90 
  miles, and the terrain was never, ever flat. It is hard to imagine 
  that a group of middle-age adults could have handled an equivalently
  difficult 10 days of running. What, I wondered, made bicycling 
  different?

  It turns out that others, too, have been struck by the paradox of 
  bicycling fitness.

  “When I first got into cycling, I would see cyclists and say, ‘O.K.,
  that’s not what I perceive a cyclist to be,’ ” said Michael Berry, 
  an exercise physiologist at Wake Forest University. Dr. Berry had 
  been a competitive runner, and he thought good cyclists would look 
  like good runners — rail-thin and young.

  But, Dr. Berry added, “I quickly learned that when I was riding with
  someone with a 36-inch waist, I could be looking at the back of 
  their waist when they rode away from me.”[1]

The Bicycling Paradox: Fit Doesn’t Have to Mean Thin

http://www.nytimes.com/2007/07/17/health/nutrition/17essa.ht...