Is there anything you can tell me about intermittent fasting, i.e. going without food for 16-20 hours? thanks

Not necessary: Intermittent fasting is a method used by bodybuilders and the fitness community to maintain low levels of body fat. There is limited data to support this method as a long-term weight loss strategy. Every body and metabolism is different and you are best to keep a diet of whole foods, low in added sugar and refined carbohydrates and responding appropriately to physiologic hunger.