Event details | Osher Lifelong Learning Institute


Event Details 
Science Pop-Up Talks - Is Less Really More? Does Eating Less Food Increase Lifespan and If So Why and How?
*DATE CHANGE* John Speakman, Royal Society Wolfson Merit Professor, Aberdeen University “Is Less Really More? Does Eating Less Food Increase Lifespan and If So Why and How?” ABSTRACT: Calorie restriction (eating less food) is a well established paradigm for extending lifespan. Questions have been raised however as to whether the impact is due to lowered total intake of calories, or due to reduced protein intake. In this talk I will outline the history of the calories v protein issue and present some of our own work and an analysis of contemporary information to establish if it is really reduced calories or protein that mediate the life extension effect. Finally I will present a model for how we currently think calorie restriction works. BIO: John R. Speakman FRS FRSE FRSB FRSA FMedSci FRSS is a British biologist working at the University of Aberdeen, Institute of Biological and Environmental Sciences, for which he was Director from 2007 to 2011. He leads 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. Between 2011-2020, he was a '1000 talents' Professor at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, in Beijing, China, where he ran the molecular energetics group. In 2020 he moved to the Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences in Shenzhen, China where he is currently co-director of the Center for Energy Metabolism and Reproduction and Head of the Shenzhen Key laboratory of Metabolic Health. Speakman was educated at Leigh Grammar School, near Manchester, and then went to the University of Stirling where he was awarded a BSc in Biology and Psychology in 1980 and a PhD in 1984 for research on the energetics of foraging in wading birds. He was subsequently awarded Doctor of Science (DSc) degrees by both the University of Aberdeen in 1996 and University of Stirling in 2009. In 2017, he obtained a BSc in Math and Statistics from the Open University. Speakman's work focuses on the causes and consequences of variation in energy balance, and in particular the factors that limit expenditure, the genetic and environmental drivers of obesity and the energetic contribution to ageing. He is an internationally recognized expert in the use of isotope methodologies to measure energy demands and has used these methods on a wide range of wild animals, model species and humans. 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. Since 2018, he has been the chairman of the International Atomic Energy Agency doubly-labelled water database management committee, which manages a database of over 7500 measurements of human subjects made using the DLW method. A paper by Pontzer, Yamada and colleagues utilizing this database, on which Speakman was a co-corresponding author, summarized the metabolic rates of humans between 8 days and 96 years old, was published in Science in August 2021. Speakman is well known for his work on obesity, in particular for criticizing 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 criticized by others that support the original thrifty gene hypothesis. A test of the ideas involved searching for signatures of selection at loci linked to body mass index and showed consistent with the ‘drifty’ but not ‘thrifty’ gene ideas there was no evidence of strong selection at these loci. Since 2018, he has published a series of studies of responses of mice to different diets, disputing the popular carbohydrate insulin model of obesity, This work culminated in a perspective article in Science with co-author Kevin D. Hall (in 2021) highlighting the inadequacies of the carbohydrate insulin model. Speakman's group was the first to link genetic variation to differences in food consumption in humans by examining polymorphic variation in the fat mass and obesity associated FTO gene. With Aberdeen colleague Ela Krol, among others, he has published a series of over 30 papers in the Journal of Experimental Biology, which culminated in a novel hypothesis that animal energy expenditure is limited by the capacity to dissipate body heat. This idea – the "heat dissipation limit hypothesis" (HDL) was published by Speakman and Krol in the Journal of Animal Ecology in 2010. The idea is claimed to have wide implications for our understanding of many aspects of ecophysiology and ecology – such as limits on range distributions, maximum possible sizes of endothermic animals e.g. dinosaurs, Bergmann’s rule, effects of climate change etc. The idea is revolutionary because it shifts the fundamental locus of control over energy expenditure from extrinsic factors outside the animal (e.g. food supply, fractal supply system, uptake capacity), to intrinsic factors inside an animal (heat dissipation capacity). An independent review of studies of energy expenditure concluded that the HDL hypothesis provided a better explanation of the patterns of energy expenditure in endotherms than does the metabolic theory of ecology. Speakman writes a monthly popular science column for the magazine ‘Newton’ (translated into Chinese by an ex-student Lina Zhang) and has also published three popular science books consisting of the compiled English versions of these articles. Speakman's peer reviewed publications can be found at Google Scholar, Europe PubMed Central, Scopus, The University of Aberdeen, ResearchGate, and academia.edu.
Event Type : Study Groups      
Category : Science Pop-Up Talks - Series Three
Date(s) : 04/26/2022
Time : 9:30 - 11:00AM
Location : Online
Instructor : Varied, see description
Fee : $10.00
Event Status : COMPLETED