In the last century the effects of CR have been well established. Animal models of CR have not only been shown to display a decrease in mortality and disease onset (Nikolich-Zugich and Messaoudi, 2005), but have also proven beneficial to human health (Fontana et al., 2004, Walford et al 2002).

The chances of developing atherosclerosis in later life have been shown to be reduced, whilst risk factors of various other diseases (i.e cancers, cardiovascular complications) are also decreased during CR diets.

The question lies in the processes which cause the affects observed. It is difficult to determine whether it is a combination of factors, or a solitary initiator which turns on CR. The mechanisms are investigated in the current study to pinpoint the specific physiological changes which bring about the alterations.

The aim of this study was to determine the effects of:

1. • Resting metabolic rate (RMR) - Debate exists whether a lower or higher metabolic rate is favoured during    CR.
   

1. • Body composition: Lean mass (LM) and Fat mass (FM) - It has been put forward that a reduction in body fat, coupled with other physiological changes is responsible for longevity.
   

1. •Body temperature (Tb) - A lower Tb may be responsible for an enhancement in lifespan.
   

1. • Daily activity- Modification to behavioural activity is seen during CR. Rhythmic changes of activity are believed to alter due to shifts in circadium rhythms.  
   

1. • Food anticipatory activity (FAA) - The activity exhibited prior to feeding. It is thought that CR can shift meal time behaviour by altering gene expressions.