A word from Michael Mosley about the link between COVID-19 and obesity

While coronavirus can affect any of us, for people with pre-existing health conditions, the impact of being infected seems to be more severe. This is particularly the case if you suffer from something called “metabolic syndrome”, a collection of medical conditions which includes a large waist (too much visceral fat), raised blood pressure, raised blood sugar levels and raised cholesterol score.

Simply being heavier can also put you at risk. That is because excess body weight is associated with poor sleep and breathing problems, which can lead to pneumonia if you get infected by the coronavirus.

If you are currently on medication then I would not recommend starting on any form of rapid weight loss diet at this time, because it should ideally be done with your doctor’s help. Instead I would suggest switching to a Mediterranean style diet, low in sugar, but rich in healthy fats such as salmon, mackerel and nuts. Eating fruits and vegetables, as well as full fat yoghurt is also encouraged. There are lots of recipes and more advice at thefast800.com

If you are overweight, have raised blood pressure or raised blood sugars, but are not on medication then do consider The Fast 800 approach for rapid and sustained weight loss. That is how I reversed my own diabetes. Being diagnosed was a wake-up call, so I took part in a BBC2 Horizon documentary to find out if I could reverse my diabetes without medication. In the course of making that documentary I invented the 5:2 diet, lost 22lbs, brought my blood sugar levels back into the normal range, where they have stayed ever since.

The 5:2 diet has since evolved into The Fast 800, which encompasses three dynamic approaches to achieving weight loss and better health. First, The Very Fast 800, which involves consuming 800 calories per day for up to 12 weeks. It’s great for those wanting to lose weight rapidly and/or have a lot of weight to lose, or as a motivating kickstart for those who plan on transitioning to the New 5:2 after a few weeks.
Second, The New 5:2 is an updated version of the original 5:2 diet, which is eating 800 calories just two days per week and not worrying too much about calories on the other five days. Fasting for two days out of seven also gives you a chance to experience the other benefits of fasting, which include:
  • Clearing-out of old or damaged cells (apoptosis);
  • Tissue regeneration through the action of switched-on stem cells;
  • Reduction in cancer risk, through a fall in levels of a body chemical called IGF-1;
  • An increase in metabolic rate, caused by a rise in noradrenaline and human growth hormone;
  • Increased levels of Brain-Derived Neurotrophic Factor (BDNF). In brain cells, higher levels of BDNF are linked to greater resistance to age-related damage; lower BDNF levels, by contrast, are linked to depression and Alzheimer’s;
  • Decreased inflammation, lowering the risk of an array of chronic diseases including arthritis, raised cholesterol, and atherosclerosis.

Why is 800 the magic number? Most rapid weight loss studies are now based on 800 calories a day, which is high enough to be sustainable and give the nutrients you need, and low enough to lead to rapid weight loss and other beneficial health changes.

You might worry about getting hungry but most people who do The Very Fast 800 say that within a very short time your hunger passes. Rapid weight loss encourages your body to switch over to fat burning. It also reduces insulin levels, increases growth hormones and boosts levels of a hormone called BDNF in the brain, which helps improve your mood.

If you do decide to lose weight this way, it will also result in a gradual fall in blood pressure and normalisation of your blood sugar levels. Both should reduce your risk of going on to develop severe complications from the coronavirus. There is no evidence this will have a negative impact on your immune system as long as you have enough protein, vitamins, minerals and other nutrients.

Both The Very Fast 800 and The New 5:2 approaches are coupled with eating a lower-carb Mediterranean-style diet, which is rich in vegetables, protein, fibre and healthy fats. Whilst during these phases we encourage you to count calories on your fasting days, the overall goal is to embrace a lifestyle and learn the foods and portions that support your health so that – once you achieve your goals – you no longer have to focus on counting your calories or any other macro nutrient. Rather, you will have an innate sense of knowing the right choices to keep you feeling well.

Thirdly, for those who don’t need to lose weight, or just want to maintain a healthy weight and reap the many evidence-backed benefits of a Med-style diet, the Way of Life approach to eating is ideal.

The combination of the three approaches is a lifelong flexible lifestyle that provides you with options when your circumstances or goals change. Trying to shake the last 5kg? You might choose to do a couple of weeks of The Very Fast 800. Going on a long holiday? The New 5:2 can help offset some of the more indulgent days. Life getting chaotic and you just want to eat well without thinking too much? Way of Life it is.

During this period of social isolation you can join The Fast 800 online programme for the added support you may need to help you stay fit and healthy. Not only will you be given a tailored meal plan, but you will be able to access a fantastic array of recipes (many that are suitable for vegetarians), lists of ingredients to buy or draw on from your store cupboard, and a fitness plan which is specific to your level. You’ll also get access to an interactive forum which is full of others currently using the plan – and communities sharing and supporting are vital to us at the moment.

You’ll also get access to The Fast 800 health coaches who monitor the forum and can offer support. There is an extensive video library of HITT exercises and mindfulness programmes – perfect for helping you stay physically and emotionally fit at this very trying time, as well as lots of tips from myself. We send you weekly updates with fresh information, fresh tips and loads more ideas to keep you motivated.


Looking to try the Fast 800 but need some extra recipes, advice and support? Try out the 12 week programme! All costing you less than a daily cup of coffee. 

The Fast 800 12-Week Programme

Providing the support, flexibility and guidance to help you lose weight and achieve true lifestyle change. All costing you less than a daily cup of coffee. Find out more!

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