Variation in Metabolic Rate: where does it come from and does it matter?

This symposium was originally scheduled for 23-26 March 2020. It is a reflection of how fast our worlds changed in that month that we only decided to call the meeting off on 13 March, yet by the 23 March, the UK was in a complete pandemic lockdown. Given what happened next, it seems a minor miracle that we were later able to reschedule the meeting for 2022 with almost all of the original planned participants. The rescheduled event was a huge success, with all delegates commenting on the joy of once more being able to interact freely with their peers at a live meeting.

The theme of the symposium was an investigation into what we know about variation in metabolism among individuals. The metabolic rate of an animal reflects the rate at which it is consuming nutritional substrates to generate ATP, the fuel that drives cellular processes. Comparisons across species can give the misleading impression that body mass explains all of the important variation in metabolic rate. However, recent studies have revealed that some individuals of a species can have 2-3 times the ‘cost of living’ as others of the same size, nutritional state, sex and age. Our aim was to explore the causes and consequences of this variation in both minimal and maximal rates of metabolism. The first part of the meeting addressed the scale of variation in metabolism found at the whole-body level; this was followed by examination of the underlying molecular and cellular drivers of this variation. We then explored how variation in metabolic rate was linked to behaviour, environmental tolerance, life history and the rate of ageing; the final session was devoted to the evolutionary selection pressures driving this variation. Speakers covered the range of disciplines from human nutrition and sport science through to cellular biochemistry, ecology and evolutionary biology. This breadth of coverage in both study organism and approach was immensely fruitful, since there were great insights to be gained not only from the discoveries of each discipline, but also from hearing about the approaches, techniques and opportunities that they offer. The discussions (both timetabled and informal) were endlessly stimulating, and led to the agreement amongst all contributors that a joint ‘opinion’ paper should be written to capture some of the main messages to emerge from the symposium – this is currently in preparation.

All participants thanked the Rank Prize team for providing the tremendous support and flexibility to allow this rescheduled meeting to take place; small focussed meetings such as this that bring together scientists in new interdisciplinary groupings are always valuable, but never more so than after a period of enforced separation.

Professor Pat Monaghan (University of Glasgow)

Professor Neil Metcalfe (University of Glasgow)

Professor Sue Ozanne (University of Cambridge, Rank Prize Nutrition Committee)