as opposed to being caused by sleep apnea, high blood pressure, metabolic changes etc.
The general idea is that the human body was designed to survive for a million years on a very wide variety of foods, but only in the last 10,000 with agriculture we have added A LOT of grain and other previously non-edible foods and our genes have not caught up to that. No one proposed hunting it yourself but I think I always fall into the "gotta have 3 meals or STARVE!" idea, and perhaps my body wasn't designed for that constant a stream of food.
There is also the idea of Evolutionary Fitness - workouts which mimic what the proto-humans did would have the most benefit (such as lots of walking, and outrageous bursts of energy).
http://www.arthurdevany.com/2005/09/twins.html
It sounds like Tabs is doing the caveman thing and it is working.