Jonkheer Alexander "Dr. Xand" van Tulleken (born 18 August 1978) is a British doctor and TV presenter. He is best known for presenting the CBBC children's series Operation Ouch! with his identical twin brother Chris, and the Channel 4 show How to Lose Weight Well.Van Tulleken has presented many documentaries, including an episode of Horizon discussing male suicide and a BBC programme on the European migrant crisis. He can often be seen offering up his own body for science experimentation in diet show How to Lose Weight Well, as well as in BBC Horizon episodes "Sugar vs Fat" and "Is Binge Drinking Really That Bad?" As of July 2023, he was appearing regularly on the BBC1 weekday programme Morning Live, providing a variety of medical advice. Van Tulleken is also a member of the "Made of stronger stuff" podcast on BBC Sounds. Source: Wikipedia (en)