The 5:2 Diet: What’s All The Fuss About?
By Paris Owen BSc (Nutrition) Nutrition & Dietetics Student
Call me old fashioned, but when I first heard about the 5:2 diet- commonly known as the ‘fast diet’ I thought, Duh! They’ve been saying this for years. 2 fruit, 5 veggies. Nothing fancy here. It wasn’t until I looked further when I found how completely wrong I was! I don’t know about you, but I am extremely skeptical when I hear about new diets. I therefore thought it was necessary to delve a little further and find the cold hard facts.
WHAT IS IT?
The 5:2 diet is based on a fancy principle known as ‘intermittent fasting’. This simply involves eating what ever you want for 5 days of the week (literally!), whilst fasting on the other 2 days, consecutively or inconsecutively. Fasting days involve consuming no more than 500 calories (2,100kJ) for women and 600 calories (2520kJ) for men. It first came about after a documentary named Eat, Fast and Live Longer was broadcast on BBC Horizon in August 2012, featuring founder Michael Mosley. It is actually a very interesting and insightful documentary, however it should be noted that this is an individual case study and it doesn’t accurately reflect the wider population.
If you would like to check it out, head here.
WHAT’S IN IT FOR ME?
It is suggested that this diet can assist not only with weight loss, yet also with reducing the risk of developing chronic diseases like heart disease, type 2 diabetes, some cancers, Alzheimer’s disease and even lengthening life! The reason that weight loss is achievable with this diet is the same for most others- you are simply restricting your calorie intake. What is different to other diets is the ‘fasting’ component, which is said to deliver benefits by decreasing the production of a hormone known as ‘Insulin-like Growth Factor’ (IGF-1).
DOES IT WORK?
Sounds too good to be true, right? Well there have actually been some surprisingly promising results in mice and other animal studies. One mice study actually found that those placed on the intermittent fasting diet had a delayed onset of Alzheimer’s disease of 6 months-1 year (which is equivalent to 30 years of human life!). See the study.
Unfortunately, as good as this all sounds- we aren’t mice. Nor will we ever be (maybe in my Harry Potter fantasy world). Therefore results from human studies have not shown similar, or as successful outcomes. The evidence at the moment is showing similar outcomes for intermittent fasting compared to continual calorie restriction (i.e. restricting energy by 25% everyday). This is seen in a major human study published in 2010 by the International Journal of Obesity, which found both diets to be equally effective for weight loss and for improving markers of chronic diseases.
In this study, those undergoing intermittent fasting actually ate according to their energy requirements on their non-fasting days. This is a core difference to the actual 5:2 diet, who’s co-founder Mimi Spencer writes that ‘little thought to calorie control’ is necessary on these days. The study also found that only 58% of those on the intermittent fasting diet, as opposed to 85% on continual calorie restriction planned to continue with it.
So far, the 5:2 diet does not seem to have any superior benefits to general calorie restriction for weight loss or preventing chronic disease in humans. It fails to promote a healthy way of eating, focusing more so on quantity than quality. It may however be an alternative weight loss method for those who find this approach easier and attempted and failed other weight loss methods.
Harvie, MN, Pegington, M, Mattson, MP, Frystyk, J, Dillon, B, Evans, G, Cuzick, J, Jebb, SA, Martin, B, Cutler, RG, Son, TG, Maudsley, S, Carlson, OD, Egan, JM, Flyvbjerg, A, Howell, A 2010, ‘The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomised trial in young overweight women’, International Journal of Obesity, vol. 35, no. 5, pp. 714-727. < http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3017674/>.
About the authors, the 5:2 fast diet, viewed 29 September 2014, <http://thefastdiet.co.uk/about-the-authors/>.
Mimi Spencer, How to do the fast diet, the 5:2 fast diet, viewed 29 September 2014, <http://thefastdiet.co.uk/how-to-do-the-diet/>.
Hi fellow food lovers! My name is Paris Owen and I am currently undertaking a Masters in Nutrition and Dietetics at University of Wollongong. I am also a university-qualified Nutritionist, graduating last year with a Bachelor of Science in Nutrition. I work with Body Bloom, a women’s fitness training group, providing specialised sports nutrition advice and meal plans. Bondi Farmers Markets is where you will find me on Saturdays making nutritious goodies with an incredible team at the Inside Out Nutritious Goods stall.
I like to take an evidence-based approach for nutritional recommendations to ensure the best health outcomes for each unique individual. I also like to approach health in a holistic way incorporating physical, mental and spiritual wellbeing. In the future, I will become an Accredited Practicing Dietitian, working in the public health system and eventually, in private practice. I am particularly interested in food allergies and intolerances and sports nutrition, however there are so many other areas I am yet to discover!