Part of what's missing from this is an explanation of how bears feed before they go into hibernation. Bears are opportunistic in the extreme when preparing to hibernate - they feed single-mindedly on the easiest, most plentiful sources of calories they can find. There's actually some evidence to suggest that the bears have a means of knowing what's calorie rich (maybe through flavor? I dunno). It's well documented that salmon-fed Alaskan bears rarely eat the whole fish - they just yank off and eat the skin, which has the most fat and, consequently, the highest calorie-to-volume ratio.

They obliquely refer to this with the example about the black bear eating moths until full, then going off to nap. He found a good source of calories, ate his fill, then stopped because he couldn't eat anymore.