A majority of people will regain a lot of the weight back as soon as they go back on carbs. And that only makes sense — retaliation, from a nature’s evolutionary standpoint, was a trait human beings were favoured to possess. A savage attack on one of our tribe-members warranted a gruesome retaliation in the form of killing. After all, it reduces the chances for such an event to occur to our next of kin, our genetic successors. And so we essentially return to our roots with our unwise decisions after the torment of arduous diets — we become savages.