My friend had been on intermittent fasting for at least over a year, he had lost a lot of weight (over 35 lbs), even though he is not overweight to start off with. Now he looks very scrawny, not as robust as before. He told me he recently had a 3 days fast and plans on doing it once a month. But he seems to be lack of energy and he sleeps very poorly. Not sure if there's anything connected to this fasting. He is also a vegan and one would think his lipids would be ideal but it's not. Actually his fasting glucose was over 100!