The roles of calorie and protein intake in the extension of life and health span.

Dietary restriction – the procedure of eating less food, is the most robust and repeatable environmental manipulation to impact both lifespan and health in later life (called healthspan). The phenomenon was discovered in the early 1900s and while not universal has been shown to impact life and healthspan in a wide range of species- including non-human primates. Randomised controlled trials in humans suggest that humans show similar physiological responses to animals on CR lending hope that enhancing our understanding of the phenomenon in animals will provide benefits for human health. Although it has been studied intensively for many years the mechanisms by which it has its effects are only poorly understood. Although it is often also called ‘calorie restriction’ (Speakman and Mitchell, 2011), in recent years there has been much debate about whether the effect on life and healthspan is actually because animals under calorie restriction regimes are also given less protein (Speakman et al 2016). This critical evidence has been acquired in studies of both Drosophila and mice (Jensen et al. 2015; Speakman et al. 2016). However, these studies are confused because there is a major protocol difference between the studies which suggest reduced calories are most important, and the studies which suggest reduced protein is more important (Speakman et al 2016). The aim of this PhD project is to resolve the different effects of these protocols using both mice (in Aberdeen) and Drosophila (in Edinburgh). The candidate will be primarily based in Aberdeen but will spend a protracted period in Edinburgh during year 2 of the project.
The successful candidate will be trained and apply for a Home Office personal licence to perform animal experiments under our existing Project Licence for which all procedures have been ethically reviewed. Training will be given in a range of in vivo experimental skills for monitoring aspects of animal energy balance: which includes surgical implantation of monitoring devices, non-invasive x-ray and MRI analysis of body composition and measurement of gas exchange in short and long term calorimetry devices. All work will be carried out under the ARRIVE Guidelines. In Edinburgh the candidate will be trained in the design, implementation and analysis of complex multivariate experiments using Drosophila as a model species and will learn techniques for assaying and analysing traits such as behaviour, growth, survival, immunity etc and how these vary with age.