I can jump in here. I lost 16kg on a ketogenic diet.<p>My gut is a lot happier as evidenced by more regular and better (firm, soft, not runny) bowel movements.<p>There is a definite smell (breath) associated with ketosis. It varies by person but it is often noticeable.<p>I asked my wife to track it as it&#x27;s very hard to notice it yourself and she says that my system produces a slightly metallic smell the isn&#x27;t objectively bad, just different to normal.<p>I have Muslim friends and during Ramadaan there is a noticeable smell which is subjectively bad from some of them.<p>A friend who works as a nurse in a very low income area says that she can detect someone who isn&#x27;t eating normally by the smell - very important to spot if that person is also pregnant.<p>It&#x27;s a long way of saying: yes there is a smell, it varies by person.