Was the prohibition on eating dinner health advice? This fascinating article describes the Buddha as data driven ascetic.


  Buddha took a different approach: His rules were grounded in his own
  experience. Like a lot of us, he tried some crazy diets. But what
  worked for him was very simple. He gave little advice about what his
  monks should eat, but he was very particular about when they should
  eat it. His followers were basically free to eat anything they were
  given — even meat — but only between the hours of dawn and noon.
  
  Like any good data scientist, Buddha learned to ignore the outliers.
  Buddha didn’t give a mystical or supernatural explanation for this odd
  time restriction. But he was pretty sure it would improve their
  health. He had tested it on himself. “Because I avoid eating in the
  evening, I am in good health, light, energetic, and live comfortably,”
  he explained. “You, too, monks, avoid eating in the evening, and you
  will have good health.”


The article goes on to discuss the empirical results of calorie restriction diets with mice.

Now, what I'd like to know, is there any grounds to believe that the Buddha had health in mind when he suggested not eating dinner?

I've read that many vinaya rules were based on how the laity would see the Sangha- eat lots would make the sangha look like gluttons, so they only took two meals. 

Also, Nikaya Buddhism's central problem to be solved was desire &amp; aversion, so it was the fixation on hunger that was the problem, not that dinner was making one fat, unhealthy or short-lived.
My recollection is the rule about not eating after noon was to stop monks going on alms round at inappropriate times of the day, including at night, where they could frighten lay people. You can research the 'Vinaya' for this. 

There certainly is a sutta where the Buddha states he enjoys good health by eating once a day but my recollection is that is not the rationale, which is why many monks today eat twice per day. 


  When these staple foods go beyond their time limit (i.e., after noon) a bhikkhu will incur an offence if he consumes them. The original
  story shows the complications that can arise from leaving the
  monastery at the wrong time:
  
  The 'group-of-seventeen' bhikkhus — another set of frequent misdoers — went out one afternoon to enjoy themselves at a festival outside the
  city. When lay people saw them they gave them a meal and food to take
  back to the monastery. The Buddha therefore laid down this rule:
  
  "Should any bhikkhu chew or consume staple or non- staple food at the wrong time, it is [an offence of Confession.]" (Paac. 37; BMC p.362)
  
  http://www.accesstoinsight.org/lib/authors/ariyesako/layguide.html#begging