Basically as we age, the insulin response becomes less efficient.
So what you could do at 25, is harder, or impossible at 40+.

Eating once a day would be an insulin spike. When this happens, the food, is rapidly stored, as there is a time element for glucose to move around the blood. So in effect one would have a rapid onset of insulin, and it would fall. Then there could be a reactive low blood sugar (hypoglycemia).

Low blood sugars starve neurons and other cells.

Another factor is alcohol. Diabetics know this well... but consumption of alcohol, results in low blood sugars as well.
This is because of the liver metabolism of alcohol.

The video:
http://www.youtube.com/watch?v=dBnniua6-oM
This is a long video, and deals with obesity, but around the middle mark, is an explanation of the liver metabolism of fructose, and alcohol.

This article explains more:
http://www.medicinenet.com/alcohol_a...tion/page4.htm

Basically, eating only once a day...a large meal, and drinking alcohol, could lead to periods of time when blood glucose is low, hence starving cells and neurons. Eating throughout the day small amounts, lowers insulin spikes, and helps prevent the LOWS which are problematic. Our doctors today do not attend to the LOWS... only highs. They only look for "diabetes" and not other forms of impaired glucose utilization.