Richard Johnson, MD explains how bears fatten up in fall by eating fruit, develop insulin resistance and fatty liver, then survive 4-6 months of hibernation living off stored fat. He explores what triggers this seasonal metabolic switch and what it reveals about human obesity.
Chapters
Hibernating bears, they'll stay. They'll keep their weight completely normal during the summer. And then some point late fall, they just change their behavior. They become hungry, very hungry, and they start eating a lot more food. They start putting on a lot more weight, they become fat, they become insulin resistant, they get fatty liver and then and high fats in their blood. And then when they're really, really fat, they'll hibernate in a den. They won't pee, they won't eat. They can go for four to six months without eating. And during that time, they live off their fat. And when they burn the fat, they're also producing water because when you break down fat, you generate water. So they're really living off the fat for both their calories and their water. So we were wondering what triggers the switch in the bear. And one of the things that's very notable is that in the fall they start eating huge amounts of fruit.