Lessons from Dr Michael Mosley: Intermittent Fasting

Dr Michael Mosley has left an incredible legacy that will continue to inspire a movement for better health. We will honour his legacy by reflecting on the lessons Michael taught us, covering topics including food, sleep, fasting, exercise, and the secrets to leading a happy life. 

Michael taught us about the benefits of intermittent fasting; intermittent fasting has been shown to improve insulin response, autophagy for cell regeneration, and metabolism efficiency, as well as reduce your risk of various cancers, neurological disorders and cardiovascular disease.^1,2,3,4 It’s also highly effective for weight loss, which is most often why people choose to follow this lifestyle.

Dedicating years to research, Michael wrote a collection of best-selling books to educate the world on the power of intermittent fasting, explaining the science in simple terms, and making the lifestyle simple to understand and follow. His books and diets changed people’s lives for the better.

What is Intermittent Fasting?

There are many different types of intermittent fasting, but there are two main forms in particular that Dr Mosley advocated: time-restricted eating (TRE) and the 5:2 diet. The latter is an eating pattern Dr Mosley discovered when he reversed his type 2 diabetes back in 2012. It involves eating just 800 calories a day two days a week, and eating a balanced, Mediterranean-style diet on the other five. 

Similarly, time-restricted eating, or TRE, involves reducing the window in which you eat by extending your fast further into the day. For example, a 16:8 pattern would be fasting for 16 hours and eating within an 8-hour window. If you’re new to fasting, we recommend starting at a 12:12 pattern and then gradually changing your habits to achieve a 14:10 method. The 14:10 pattern is a sustainable method and was the model Dr Mosley chose to follow long-term himself. The extra downtime for your internal systems allows more energy to go to cell repair pathways to engage fully, and can result in various health benefits.

What Dr Michael Mosley taught us

Dr Mosley was so instrumental in the popularisation and awareness of these eating patterns that we wanted to honour his work by sharing some of the lessons we’ve learnt from him about intermittent fasting.

1. 800 calories is the magic number: He named his bestselling book and brand ‘The Fast 800’ after the magic number of 800 calories at which we begin to reap the benefits intermittent fasting has to offer. Although Dr Mosley’s initial attempt at a 5:2 fasting regime was at 500-600 calories a day, he soon found that 800 calories was more sustainable and just as effective at ‘flipping the metabolic switch’. It may sound like you’d be hungrier on fewer calories but once your insulin sensitivity improves, you feel fuller on smaller portions. That said, it’s no good to use up all your daily calories by eating a cheeseburger and calling it a day. Dr Mosley highlighted the importance of eating healthy calories when restricting your caloric intake, which leads us to our next point.
2. Quality and quantity: The quality of your calories is just as important as the quantity when trying intermittent fasting. Although on a 5:2 diet, you’re able to eat with no calorie restriction for five days a week, you should still follow a balanced, Mediterranean-style diet if you want to experience the full benefits it has to offer. A Mediterranean-style diet has been shown time and time again to be one of the healthiest eating patterns. Its nutrient-dense focus on healthy fats, protein and fibre can reduce your risk of chronic illness like cardiovascular disease, neurological disorders, metabolic syndrome and type 2 diabetes while improving your sleep, longevity, mental health and weight loss.⁵ Dr Mosley always highlighted how vitally important it is on fasting days to still prioritise 60g of protein and 30g of fibre to stay nourished, energised and full.
3. Intermittent fasting and sleep: Similarly to the way a Mediterranean diet can improve your sleep, intermittent fasting has the power to transform your rest and sleep quality. Research shows that optimal sleep improves your metabolic health and that getting eight hours of quality rest a night can support your immune system, aid weight management and improve your mood.⁶ So, it’s worth bearing in mind that fasting short term can improve restlessness, awakenings during the night and leg movement during sleep and ultimately improve your sleep.⁷
4. Fasting and brain health: Just as intermittent fasting can improve your sleep, it can also boost concentration and emotional regulation.⁸ Studies have shown that in the longer term, intermittent fasting can actively counteract disease processes in a range of age-related disorders like Alzheimer’s, Parkinson’s and stroke.⁹ Dr Mosley always advocated for the way that fasting can boost your productivity once you’ve flipped your metabolic switch.
5. Try what works for you: Dr Michael Mosley reported that he was a breakfast person, tending to wake hungry, so when he fasted intermittently he would prefer to have breakfast and finish eating three hours before bed. However, if your lifestyle works better with a later evening meal, then start your eating window later in the morning. Dr Mosley also shared that diets like the 5:2 diet can be adjusted to be 4:3, for example, depending on what works for you. The beauty of intermittent fasting is how flexible it is while still providing health benefits; choosing your fasting windows and days to align with your lifestyle will help it to become a more sustainable habit, yielding better results. It’s unique to you!

Michael’s work will continue to influence health and policy decisions around the globe. An example of this is the publication of a recent clinical trial in China that found that the 5:2 approach was more effective than both metformin and empagliflozin for both weight loss and improving HBA1c levels. This study is further validation of the principles that Michael stood for and will show that his work will continue to be of significant importance.¹⁰

Dr Mosley’s work in the field of intermittent fasting helped bring it to the masses and benefit countless people’s lives, and we aim to continue his legacy.