AHS17

The conflation of ketogenic diets with starvation has led to confusion and alarm about their effects on hormones. Humans and many other animals are naturally in ketosis under sufficient caloric restriction, but in most animals, ketosis is difficult or impossible without it. In contrast, ketosis is easily achieved in humans as long as dietary carbohydrate is limited. This means humans can be in ketosis without suffering undernutrition. There are significant benefits associated with caloric restriction, many through mechanisms in common with ketosis. Likewise, there are similar hormonal effects seen in caloric restriction and ketogenic diets. Because ketosis and starvation have been conflated, hormone levels in ad libitum ketogenic dieters that resemble those in caloric restriction are sometimes taken as signs of stress. In this presentation, I will show why the changes in thyroid and cortisol that accompany ketogenic diets should be considered beneficial, not dangerous.