It’s the ground-breaking diet with a global following: eat what you like five days a week, fast for two, and get healthy.
According to scientific testing backing the diet, cutting your calories for just two days a week (500 for women, 600 for men) will see you not only lose weight, but also lower your risk of a range of diseases, including cancer, heart disease and diabetes.
Sounds like a miracle diet. But how would such ‘fasting’ affect your performance at work?
The biggest concern for many people thinking about attempting the ‘5:2 Diet’ is that fasting will leave them feeling lightheaded and unable to concentrate.
Dr Michael Mosley, author of the international best selling book, The Fast Diet, claims that fasting has actually had a positive effect on his mental acuity. “I thought that fasting would make me distractible, unable to concentrate. What I’ve discovered is that it sharpens my senses and my brain,” he writes.
Dr Mosley explores the link between hunger and brainpower through an evolutionary perspective. During times of famine our primitive ancestors would have had to think clearly and make quick decisions. Dr Mosley asks Mark Mattson, Professor of Neuroscience to explain the theory:
“If an animal is in an area where there’s limited food resources, it’s important that they are able to remember where food is, remember where hazards are and so on. We think that people in the past who were able to respond to hunger with increased cognitive ability had a survival advantage”.
So how might a modern day human fare in the new ‘hunting ground’, the workplace?
“Some people may function well on a fast day while others will find it interferes with their work performance”, says Pip Golley, Accredited Practicing Dietician and spokesperson for the Dietitian’s Association of Australia (DAA).
Farhat Zaheer-Flaherty, senior brand developer at meerkat.com, started the Fast Diet in January after watching the BBC Horizon documentary Eat, Fast and Live Longer. Farhat hasn’t observed any negative effects at work and says, “I don’t find it harder to concentrate, or find myself flagging”. However, she does admit that she can, “Get a bit grumpy towards the end of the day”.
Being a “bit grumpy” might not be an obvious problem in terms of your overall performance, but anyone who works closely with other people and particularly those in customer facing positions should be aware that fasting could affect their mood.
Golley says other symptoms that might have a negative impact at work include fatigue, shaking or trembling and light-headedness.
Golley warns that the 5:2 Diet is not recommended by the DAA, but advises: “For those who insist on trialling the Fast Diet in the workplace, it’s important to plan ahead, include fresh fruit, legumes and vegetables, some protein and low GI foods and plenty of water”.
No one can predict how this diet may impact your individual performance at work, but as Dr Mosely says: “The best predictor of success with any diet is how you cope with the first few weeks”.