Does it differ for intermittent vs. continuous calorie restriction?
Whilst biologists interested in the ageing process have shown excitement regarding the positive effects calorie restriction potentially has on life longevity, researchers from the eating disorder field are concerned about the psychological implications, such as an increase in eating disorder symptomology and negative impact on mood. The highly popular 5:2 ‘Fast Diet’ (Mosley & Spencer, 2013) consists of calorie restriction by encouraging intermittent fasting; followers restrict their calorie intake to 25% of their daily allowance on two days per week, and eat as normal on the other five days. Despite contradictory evidence for the psychological impact of calorie restriction, thousands of dieters are undertaking the programme with little or no supervision or warning of the potential risks. As a result, a previous UCL thesis project (Langdon-Daly, submitted) aimed to systematically investigate the impact of commencing the 5:2 diet on individual’s psychological wellbeing and disordered eating symptomology, particularly those who might have been considered ‘at-risk’. Whilst results suggested the diet had a positive impact on these factors, a lack of control group meant it could not be concluded whether this was a result of calorie restriction in general or specific to the intermittent fasting type. Furthermore, the study suffered from high attrition rates and the method used did not allow for data collection of those who ‘dropped out’ of the diet; it was therefore impossible to establish whether such individuals also benefitted from the intermittent fasting diet, experienced no change or in fact felt adverse effects. This study therefore aims to build upon Langdon-Daly’s research by introducing a continuous calorie restriction control group and allowing for data collection of those individuals who prematurely finish their diet protocol. This study aims to answer the following questions:
- Does commencing the 5:2 diet result in greater changes on measures of ED symptomology and other related experiences such as binge-eating and preoccupation with food/food craving in comparison to commencing a CCR diet?
- Does commencing the 5:2 diet result in greater changes on measures of mood factors such as depression and irritability in comparison to commencing a CCR diet?
- Does commencing the 5:2 diet lead to a greater increase in eating disorder symptomology or experiences such as binge eating and preoccupation with food/food craving in individuals who could be identified as ‘at risk’ of developing these kinds of difficulties, in comparison to commencing a CCR diet?