Revive Reviews: The Fast Diet

The traditional approach for weight loss that health care professionals use is calorie restriction over the long term.  The Fast Diet, a new book written by Micheal Mosley and Mimi Spencer, has a different approach:

“Is it possible to eat normally, five days a week, and become slimmer and healthier as a result? Yes. You just limit your calorie intake for two non-consecutive days each week- 500 for women, 600 for men.  You’ll lose weight quickly and effortlessly with the Fast Diet!”

I can honestly say I have yet to meet a person who thought their journey of weight loss was effortless regardless of which path they chose.

Thankfully there have been some research studies done in this area that we can discuss.  While the intermittent fasting (25% restriction (not as limited as The FastDiet) for 2 days per week with no restriction for the other 5 days) has shown to be effective for people losing weight, the longest study to date is 6 months (1).  They concluded intermittent fasting was equally as successful as energy restriction (25% calorie restriction 7 days per week) for weight loss.  They did find fasting insulin levels were a little better in the intermittent group compared to the energy restriction group.

What I find most interesting about this study is that when asked 58% of people in the intermittent fasting group would choose to continue eating this way once the study was done compared to 85% of the calorie restriction group.  And the intermittent fasting approach was no easier to adhere to than the calorie restriction approach.  Perhaps not so effortless …

Of the 4 studied, the consensus is the same.  Yes intermittent fasting does work but the question you should be asking yourself is- Are you able to maintain it for the long run (AKA the rest of your life)? Also note that the diet is not recommended for pregnant women, those under 20, diabetics and more…


Revive Wellness is a team of passionate and evidence-based Registered Dietitians specialized in nutrition and wellness coaching for the Edmonton area.

Ready to Ditch the Diet for Good?


  1.  Michelle N. Harive, et al.  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. 2011 May; 35(5): 714-727
  2. Leonie K Heilbronn, et al.  Alternate-day fasting in nonobese subjects: effects on doby weight, body composition, and energy metabolism.  American Journal of Clinical Nutrition 2005; 81:69-73
  3. 3.       Samira Eshghinia and Fatemeh Mohammadzadeh.  The effects of modified alternate-day fasting dies on weight loss and CAD risk factors in overweight and obese women.  Journal of Diabetes and Metabolic Disorders.  2013, 12:4. 1-4
  4. Monica C klempel, et al.  Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women.  Nutrition Journal. 2012, 11:98. 1-9.