|Fields||Energetics and Obesity|
|Institutions||University of Aberdeen|
|Notable awards||FRSE (2004)
FMed Sci (2008)
Professor John Speakman FMedSci is a British biologist working at the University of Aberdeen, Institute of Biological and Environmental Sciences. He directs the University's Energetics Research Group, which is one of the world's leading groups using doubly labeled water (DLW) to investigate energy expenditure and balance in animals. During the mid-1980s and early 1990s, Speakman made many contributions to the development of the DLW method, culminating in the book "Doubly labelled water: theory and practice",  published in 1997 that remains the standard reference work for applications of this methodology in humans and other animals.
Speakman is also well known for his work in obesity, in particular for criticising a long-established theory for obesity known as the thrifty gene hypothesis. His alternative hypothesis proposes that the modern distribution of obese phenotypes arose via the release from predation and random genetic drift: the 'drifty gene hypothesis'.    This idea is controversial and has been criticised by others that support the original thrifty gene hypothesis. 
Speakman was awarded the Zoological Society of London scientific medal in 1995, and the Royal Society of Edinburgh Saltire Society Scottish Science medal in 2003. In 2004, he was elected to the fellowship of the Royal Society of Edinburgh, in 2008 to the UK Academy of Medical Sciences, and in 2009 to the Royal Society of Arts in London.
- Speakman, John. "Awards & Prizes". Energetics Research Group. University of Aberdeen, UK. Retrieved March 13, 2011.
- "John Speakman". Energetics Research Group. University of Aberdeen, UK. Retrieved March 13, 2011.
- "Energetics Research Group". University of Aberdeen, UK. Retrieved March 13, 2011.
- Speakman, J.R. (1997). Doubly labelled water: theory and practice. London: Chapman & Hall. ISBN 0-412-63780-4.
- J. R. Speakman. (2008). Thrifty genes for obesity, an attractive but flawed idea, and an alternative perspective: the 'drifty gene' hypothesis. International Journal of Obesity, 32, 1611-7. doi
- Speakman, J.R. (2006). The genetics of obesity: five fundamental problems with the famine hypothesis. In G. Fantuzzi, and T. Mazzone, (Eds) Adipose tissue and adipokines in health and disease. Humana Press, New York.
- J. R. Speakman. (2007). A nonadaptive scenario explaining the genetic predisposition to obesity: the "predation release" hypothesis. Cell metabolism, 6, 5-12. doi
- A. M. Prentice, B. J. Hennig and A. J. Fulford. (2008). Evolutionary origins of the obesity epidemic: natural selection of thrifty genes or genetic drift following predation release? International Journal of Obesity, 32, 1607-10, doi
- J. R. Speakman, K. A. Rance and A. M. Johnstone. (2008). Polymorphisms of the FTO gene are associated with variation in energy intake, but not energy expenditure. Obesity, 16, 1961-5. doi