" All God's creatures get fat and have high cholesterol and high blood pressure and then go to sleep, or at least starve for sugar for a while. That's why only our pets have heart disease, get too fat to walk, and have cancer. They live with us." T.S Wiley, Lights Out
In nature you could not live off sugar for very long, seeing as plants only fruit in one season and flower in the next. With seasons leaving food supply unpredictable we only had one option-obesity. A major killer now was once the key to survival. In order to put on enough fat to live off of during winter months you had to become insulin resistant when the carbohydrate (sugar) supply was available. The goal was to eat so much sugar that your muscle cells would close up shop (become resistant) to the effects of insulin and therefore store all incoming sugar as fat or pumped into cholesterol production. The evolutionary purpose of insulin is insulation.
" The point of being really fat is to keep you from starving and freezing. Insulin stores excess energy as internal fat around your vital organs first, before you ever see it ripple under your skin. The purpose is to insulate your heart, lungs, and digestive system from the cold, just as the fetus in a pregnant women is protected with a layer of fat energy."
This higher than normal insulin would flip the switch on increased cholesterol production to keep your cell membranes from freezing. The greatest evolutionary edge would come with the out of control high blood sugar seen in type 2 diabetics .
" A higher than normal concentration of blood sugar would keep the interior of your cells from freezing because of the effect carbohydrates have on water molecules. All anti-freeze, even what you use in your car, tastes sweet."
Type 2 Diabetes is truly the end-state of the vestigial hibernation instinct. The problem is we don't live in the real world anymore, the food supply (sugar) never runs out and we never turn the lights off!
" As a mammal, you are hardwired to eat sugar, make babies, store fat, and then sleep it off, and then do it again and again."