I'm no authority either, but I've worked in the field of metabolic health for a couple of years and read a few dozen studies and books on the topic. You're pre

I'm no authority either, but I've worked in the field of metabolic health for a couple of years and read a few dozen studies and books on the topic. You're pretty much correct: The most relevant contraindication for any kind of fasting are eating disorders like anorexia. Also, don't try out fasting if you're taking metabolism related medication without consulting with your doctor. A lot of research suggests that most lifestyle diseases that are prevalent in the developed world (like obesity, diabetes, heart attack, even some types of cancer and possibly also neurodegenerative diseases like Alzheimers) can be prevented and sometimes treated with a dietary intervention. The optimal diet seems to be whole foods and mostly plant-based (though some people seem to thrive on meat) with occasional fasting periods. It makes a lot of sense from an evolutionary perspective: Our ancestors didn't have all that sugary and industrially processed food and often spend extended periods fasting and searching/hunting for food. Processed foods highjack our preference for calorie rich, sweet and savory food but are often deficient in nutrients.