Your ancient DNA still works the same way as our ancestors’ did. We convert sugars (carbohydrates) into fat under the direction of Insulin. This is what makes us fatter, not eating fat! Unfortunately these misguided scientists like Keys thought it was fat in our diets that made us gain weight. But they totally neglected to look at the amount of sugars that we ate. Especially wheat.
So, you might ask why did it take so long for today’s problems to develop? After all, we’ve been making bread since biblical times. Well, the original wheat, einkorn, had 17 genes, so it produced 17 proteins. Through cross-breeding, we managed to add another 30 or so, and now modern wheat bears little resemblance to the original and produces 47 different proteins, each of which has the potential to cause inflammation or full-blown allergy. Modern wheat is so rapidly converted to sugar that two slices of your best quality whole wheat bread will raise your blood sugar as much and more faster than two tablespoons of white sugar. That forces the pancreas to constantly produce large amounts of Insulin.
The normal insulin cycle is a gentle up and down cycle to keep your blood sugar (glucose) on an even keel. It rises a little bit to clear the sugar from the bloodstream. It does this by delivering the sugar energy to the cells that need it. And insulin goes down when the sugar levels are low or normal. But when the glucose levels are too high, the cells will not accept it from the insulin and they turn off their ability to respond to insulin. This is known as Insulin Resistance. But we can’t live with high circulating blood sugars, so the fat cells take up the excess sugars and convert them to fat. And in the presence of Insulin, fat cells cannot release this fat. Insulin resistance leads to obesity and diabetes.