Gut Reaction #18: The 5:2 Diet

October 29, 2017 0
Over the last 20 years many patients have asked for my advice on losing weight (often following a discussion about hiatus hernia, reflux or fatty liver….). It appears that all diets work (albeit some quicker than others) when people stick to them but once they end, the fat tends to re-accumulate. Some diets involve spending money on special foods or drinks or attending regular sessions. For some busy people this can be challenging and may get in the way of starting or continuing a diet.When Dr Michael Mosley and his colleagues first highlighted the 5:2 diet on BBC2’s Horizon programmes (February 2015) I was most interested as the diet was easy to follow (once the calorie content of food and drinks was established), very cost-effective and would be relatively easy for many of my working patients to follow. It is much easier to comply with a diet that only asks you to restrict your calorie intake occasionally (and allow for social or work-related lunches or dinners).

So what is the basis of the 5:2 diet? This diet involves restricting your calorie consumption to 25% of your energy (calorie) needs, two (consecutive or non-consecutive) days a week, and eating normally the rest of the time.

During the ‘fasting’ days, men should consume no more than 600 calories per day and women no more than 500 calories. The 500/600 calories can be consumed throughout the day as snacks, or as one or two meals. It is recommended that good foods to eat on a ‘fasting’ day are foods high in protein and fibre which tend to fill you up more – so foods like fish, meat and vegetables.

Further information about the diet may be found at

The proposed health effects of the 5:2 diet include weight loss, improvement in life expectancy, possible protection against certain cancers and diseases including heart disease, stroke, Alzheimer’s, diabetes and dementia. Many also report improved results in health tests like blood pressure and cholesterol testing, alongside significant, and sustainable, weight loss.

However, it is important to note that the evidence supporting the 5:2 diet is currently limited. More research is needed to look at the long-term risks and benefits. For example, I suggest that once the desired amount of weight loss has been achieved that my patients continue with a “6:1 diet” to maintain it.

For more information about the 5:2 diet as well as potential benefits/drawbacks, please do not hesitate to contact Dr. Adam Harris.

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