Odd though it sounds, last year I decided to try piling on the pounds. I didn’t go mad, but I started to put away far more toast and pasta, and indulged in lots of snacks.
It took me several months to put on a stone (over 6kg), taking me to just over 13st (my height is 5ft 11in).
Now this sounds like a pretty foolish thing to do, particularly when you consider that the reason I’d come up with the 5:2 diet in the first place was because I’d been diagnosed with type 2 diabetes and wanted to reverse it without medication. I managed to do so by losing 1st 5lb (9kg).
Putting most of that weight back on sent my blood sugar soaring back into the diabetic range. My waist ballooned from 32 to 37in and I started hiding my new paunch with baggy shirts.
My sleep was terrible and I felt sluggish, moody and hungry much of the time. I found it almost impossible to pass a shop and not buy chocolate.
Dr Michael Mosley, pictured, put on over a stone to test out his health regime, a new hopefully improved version of the 5:2
My wife, Clare, who is a GP, was monitoring my health. As the months went by, she became increasingly worried. When she told me I was looking older, greyer and that I was snoring really loudly, I knew it was time to act.
So why had I decided to put on weight? Well, it was partly because I wanted to find out what would happen when I did.
But it was mainly because I normally only recommend health regimes that I’ve tried on myself. And earlier in the year I’d put together a new, hopefully improved version of the 5:2 which I wanted to test.
When I came up with the original 5:2 diet in 2012 (where dieters ate restricted calories — 600 for men or 500 for women — for two days a week), intermittent fasting was a radical idea, but one that really resonated.
The Fast Diet rapidly became an international bestseller, translated into more than 40 languages. The diet was embraced by a wide range of people, including doctors, politicians, celebrities and Nobel Prize winners. People found it effective but it was clearly not the final word.
In the six years since, there’s been a lot of new scientific research into intermittent fasting and weight loss. I’ve also received a tremendous amount of useful feedback from people who’ve tried the 5:2.
So I decided to put it all together and create something easier and more effective. To test my new regime for practicality I needed to put on the weight so I could shed it again.
Dr Mosley, pictured, came up with the 5:2 diet in 2012, where dieters ate restricted calories of 600 for men or 500 for women for two days a week
And you know what? The new regime is better than the original. That claim is based not just on my personal experience but on lots of recent studies.
It’s why I’ve updated my plan in a new book, The Fast 800, which is being serialised by the Mail all next week.
There are a lot of refinements and improvements, from what you should eat to when you should eat it, but one thing that has become increasingly clear to me is that 800 calories appears to be a ‘magic’ number when it comes to weight loss.
Eight hundred calories a day may not sound like much but — as you’ll see in the free 32-page magazine full of calorie-controlled recipes included in this newspaper (it’s in the bag with Weekend) — if you choose the right foods then 800 calories can be tasty and filling.
But isn’t 800 calories a day a rapid weight loss diet, and aren’t they bad for you? Not if you do it right.
In the past 12 months several important studies show that, if done properly, sticking to 800 calorie days is safe and can be hugely beneficial.
Professor Roy Taylor is a diabetes specialist at Newcastle University. When we first met, four years ago, he told me the main reason I had managed to knock my diabetes on the head was because, by doing the 5:2, I had lost a significant amount of internal fat, fast.
Losing weight had drained the fat out of my liver and pancreas, restoring my blood sugars to normal. He also told me that he, and a colleague, Professor Mike Lean of Glasgow University, were about to put a rapid weight loss diet to the test by conducting a big study in general practices across Scotland and the North of England.
That study, Direct, was published in early 2018. It showed that an 800-calorie-a-day diet not only led to impressive weight loss (an average of 10kg, maintained for over a year) but also helped nearly half their patients with type 2 diabetes come off medication and restore their blood sugars to normal.
The results were so impressive that the NHS plans to carry out further trials involving more than 5,000 patients.
Another big randomised study called Droplet, carried out by Professor Susan Jebb and colleagues from Oxford University, also confirmed, in late 2018, the benefits of doing a rapid weight loss diet based on 800 calories a day, even if you don’t have diabetes. As she pointed out to me ‘the results were phenomenal, like nothing that has been seen in primary care before’.
So I decided to combine this 800 calorie rapid-weight-loss approach with the 5:2 and test it on myself — which is why I put the weight on.
Once I’d got properly paunchy again, I started on the fast track phase sticking to 800 calories a day and using recipes similar to those you will find in today’s Weekend and in the pull-outs all next week.
I added in a new fasting trick, called ‘Time Restricted Eating’ — which I also explain overleaf — and made sure I only ate food within a strict 12-hour window. My plan was to finish eating by 8pm and then not eat anything until at least 8am the next morning.
So how did I get on? Well, sticking to 800 calories a day every day was not as challenging as I feared it might be. Yes I was hungry and a bit grumpy to begin with, but after a few days the cravings and the bursts of hunger passed. Mostly.
Trying to fit this rapid weight- loss diet around a busy filming schedule meant I had to combine using meal replacement shakes when I was on the road with real food when I was at home.
In the first four days I lost an impressive 6lb. I knew some of that would be water because I was eating fewer calories than normal, but my blood sugar levels and my blood pressure fell very swiftly too.
At times my energy levels felt lower. But after just two weeks on 800 calories a day, every day, I lost 11lb and tests showed that my blood sugar levels and blood pressure were back to normal.
I decided this would be a good time to switch to the next phase of my new 5:2 and have two 800 calorie days a week, eating healthily for the other five.
As an experiment, I tried my fast days back to back (Mondays and Tuesdays) in a bid to increase the fasting benefit, and found that also helped.
On this part of the plan, I realised I had more energy and also found I could push myself harder without feeling drained. I continued to eat calorie-counted Mediterranean-style menus on my fast days and I allowed myself to eat more freely on non-fast days — even enjoying the odd glass of wine. It was, I have to admit, surprisingly easy.
Three weeks and five days after I started, I had lost a stone, and was back to my previous healthy weight. My blood sugar levels, blood pressure (and everything else) were back to normal.
So I can report, with my hand on my hopefully healthy heart, that this diet is eminently doable. So why not give it a go?
We’re proof this diet can change your life!
‘I was a size 16, but I shed 40lb and feel really great’
Penni Cuthbert, 33, an analyst, lives with husband Ryan, 30, a plasterer, and their children, Alasdair, three, and Livvy, two, in Edinburgh.
Having had two children in quick succession, the weight had crept on. I’d weighed 10st before but gone up to 13st. At 5ft 4in tall, I was a size 16 and my knees were suffering. Running around after my young children was exhausting.
Like most people, I’d tried all kinds of diets and would lose some weight, but put it back on. It was my mum, a biomedical scientist and teacher, who first brought the 5:2 to my attention.
I started it almost by accident on Valentine’s Day 2017. At 5pm, I realised all I’d had was cups of coffee. I wasn’t feeling particularly hungry and thought now was a good time to start.
Penni Cuthbert, 33, pictured left before and right now, said it took eight months to lose 40lb and that she isn’t strict on non-fasting days as she allows herself a takeaway or a chocolate bar
With 5:2, you don’t need a membership fee, you can chop and change your fasting days and no food is banned. People ask if I have to be strict on non-fasting days, but I really don’t. If I fancy a Chinese takeaway or a chocolate bar, I can have it on those days. In fact, I don’t have to think about what I’m eating on non-fasting days at all.
You need willpower but I knew I could enjoy my evening meal if I stuck to between 500-800 calories in the daytime.
Within weeks, the weight was falling off. I bought a Fitbit and I’m obsessed with getting my 10,000 steps a day. It took eight months to lose 40lb and I feel so much better. I’m now a size 10. I took the whole of August off but started again in September and now it’s simply part of my life.
‘Since June I’ve lost 2½ stone and now wear size 12’
Victoria Scott, 40, a PR consultant, lives in Shepperton, Middlesex, with her husband Teil, 43, a pilot, and their two children, Raphael, eight and Gabriella, four.
Last year I saw a photograph of myself taken from behind. I thought I still looked the same as I did before I’d had my children, but this horrifying picture proved otherwise.
I was shocked to find I weighed 14st 4lb. I’m 5ft 10in and had thought I was tall enough to carry off the weight. But my size 16 clothes were feeling tighter and I realised I was in trouble.
Victoria Scott, 40, pictured left pre-weight loss and right after the diet, decided to try the fasting regime out after seeing a picture of herself taken from behind
I researched all the diet options and liked the fact that 5:2 has lots of science to back it up. My father had type 2 diabetes and I didn’t want to end up with it.
I started slowly. On fasting days, I’d have eggs for breakfast, then a light soup for lunch and a small evening meal to stave off hunger pangs.
Then I joined several 5:2 Facebook groups where people advised not to eat anything until dinnertime when you can have a bigger meal. I tried that — drinking lots of tea, coffee and fizzy water — and found it much more convenient.
Another bonus of the 5:2 diet is that it saves money. You’re not buying ready-prepared meals or shakes. Apart from the occasional celebration, I’ve also given up alcohol.
Within a week I’d lost 3lb and within a month I’d lost my first stone. Since June, I’ve lost 2½st, and I’m now in a size 12 to 14.
‘I’m allergic to exercise, so the 5:2 diet is ideal’
Louisa Walters, 50, is the founder of The Restaurant Club, a members-only discount scheme for lovers of independent restaurants. She lives in North-West London with husband Simon, 55, a finance director, and they have two grown-up children.
When I launched my restaurant business in 2016, the pounds crept on. I rarely step on the scales. I prefer to go by how my clothes feel, so I knew I was probably half a stone or more overweight.
My husband’s birthday was coming up, so I did a quick-fix diet, which lost about 5lb, but I knew I couldn’t sustain it. That’s when I tried the 5:2 diet.
Louisa Walters, 50, pictured left before and right now, skipped breakfast while on the 5:2 and said although it was ‘hard’ it gave her ‘discipline’
I never did two fasting days together but always chose a Monday and either Wednesday or Thursday. I wouldn’t have breakfast, and for lunch, I’d have a light meal such as soup. I’d have tea or coffee with skimmed milk throughout the day.
Sometimes I’d go over the 500 calories by 100, but I balanced it out across the two days. Fasting was hard, but the 5:2 gave me discipline. If I wanted chocolate, I’d think: ‘Yes, you can, but tomorrow, or the day after, not today.’
I’m allergic to exercise, so any weight loss comes from my diet. I like doing 5:2 after a heavy weekend, because you can undo a lot of the damage.
Are you addicted to food? Take this quiz to find out
One of the things this diet will help you with is cravings. I love chocolate, particularly milk chocolate, and I know my cravings have nothing to do with hunger.
I can be ravenously hungry and walk past a shop without a second glance, but at other times, particularly when I’m tired, stressed or bored, you might find me prowling the house like an animal, desperately searching for chocolate.
I tried to wean myself onto dark chocolate, but that doesn’t fulfil the same emotional needs. Some foods have addictive qualities — but when I was doing the diet I found my cravings much reduced.
Doctor Michael Mosley goes on tour!
In February and March, I will be taking part in a series of live events in theatres across the UK.
Among other things, I will be talking about my television career and all the things that I’ve learned about nutrition over the past ten years.
If you would like to find out more, then do visit my
I am convinced the modern obesity epidemic wasn’t triggered by a sudden collective breakdown in willpower. It happened, at least in part, because over the past few decades food manufacturers have found ever more ingenious ways to make us buy their products.
Like the tobacco industry, they know the importance of hooking in their customers. Highly addictive foods are also highly processed foods, designed to be absorbed very rapidly and give your brain an almost immediate dopamine (the reward hormone) rush.
The pleasure you get from eating junk food it is normally short-lived. It is about compulsion. We eat junk food knowing it is bad for us, but we can’t stop ourselves.
Try this quiz to see how addicted you are to a particular food. More than three ‘yes’ answers and you may be in trouble:
1 When I start eating this food, I can’t stop and eat more than intended.
2 I keep on eating this food even when I am no longer hungry.
3 I eat to the point where I feel physically ill.
4 I find myself craving this food when I’m feeling stressed.
5 If it isn’t in the house I will drive to the nearest shop that sells it.
6 I use this food to feel better.
7 I hide this food so even those close to me don’t how much of it I eat.
8 Eating it causes anxiety and feeling of self-loathing and guilt.
9 Although I no longer get much pleasure from eating it, I keep on doing so.
10 I have tried to give this food up but failed.
Add up your ‘yes’ answers. The more you gave the answer yes, then the more hooked you are.
How the Fast 800 works
STAGE ONE: The Fast 800
- If you want rapid weight loss, as long as it is safe for you to do it, try sticking to 800 calories a day for a few days, weeks or even months.
- Real food is best, but while you adjust to the diet, for simplicity and convenience, consider using meal replacement shakes for up to half your daily calorie intake to suit your lifestyle, perhaps for breakfast or to take to work for lunch.
- This ‘fast track’ approach is great if you have a lot of weight to lose; if you are in a hurry; if you have pre-diabetes or type 2 diabetes; if you have been told you have a fatty liver; if you want to kick your weight-loss journey off with a bang; or perhaps because you have hit a weight-loss plateau.
- 800 is the magic number when it comes to successful dieting — it’s a calorie amount that is high enough to be manageable and sustainable but low enough to trigger a range of metabolic changes that are very good for your mental and physical health.
- Aim to eat within a 12-hour window (9am to 9pm or 10am to 10pm) to maximise the health benefits of your overnight fast.
STAGE TWO: THE NEW 5:2
- Pick two days each week when you will stick to 800 calories (the days can be consecutive or separate).
- On these ‘fast days’ aim to eat within a 10-hour window (so your nightly fast is extended to 14 hours).
- The fasting options can be varied according to your need; the 2:5 with two non-fasting days and five ‘fast days’ — if it is difficult to fast at weekends — or adding extra ‘fast days’ to speed things up with the 3:4, or maintaining the metabolism in good shape with the 6:1 involving only one ‘fast day’ a week.
- Aim to maximise your nutritional intake by following the recipe ideas in today’s magazine and all next week in the special pullouts in the Mail.
- On non-fast days, eat healthily. No calorie counting, but keep an eye on portion sizes and aim to stick to a Mediterranean-based diet.
5:2 all the way
I’ve designed this diet plan to be flexible so you can tailor the programme to your needs, goals and motivation.
You can switch from stage one to stage two whenever you like, or you can cut out the first stage and start at 5:2 as long as you eat 800 calories on your two ‘fast days’ and aim to eat healthily the rest of the week.
STAGE THREE: A HEALTHY WAY OF LIFE
- Once you’ve achieved your ideal weight, make sure you stay there by sticking to my super-healthy Mediterranean-style recipes.
- No calorie counting, but do watch portion sizes. Eat the foods you love, but in much smaller quantities than you used to.
- Aim to eat within a 10 or 12-hour window, always.
- Weigh yourself regularly and if it starts to creep up, try 6:1 (one day per week on 800 calories).
BUT Why HAVE Time- Restricted Eating too?
- There is strong scientific evidence that extending your overnight fast — going for 12, 14 or even 16 hours without calories — brings benefits.
- This extended break gives your body a chance to switch its priorities away from digestion and on to other important functions, such as ‘autophagy’. This is the clearing away of old cells to make way for new ones. An extended overnight fast will also help your body switch from burning sugar to burning fat — YOUR fat!
- Studies suggest the best results from eating within an eight or nine-hour window, but that may not be practical. Start by trying to confine your eating and drinking to 12 hours.
Can I still have a glass of wine (or two)?
It’s A good idea to try to lower your alcohol consumption while on the plan. Alcohol lowers your inhibitions. Another reason? It is extremely calorific. A large glass of wine (250ml) or a pint of beer comes to around 230 calories, similar to eating a small chocolate bar or an ice-cream.
But there’s no reason not to enjoy the odd glass of wine (preferably red) on non-fast days and when you reach your goal weight.
Keep on moving
If you already have a regular exercise programme, keep going — on ‘fast days’ and non-fast days. If you don’t do regular exercise, this is a good time to begin.
Start with a few brisk walks and add in some light resistance exercises, such as push-ups and squats. These should increase in frequency and intensity as the weeks go by.
Exercise will improve sleep and will help fat burning, which will increase the effectiveness of the diet.
Don’t use exercise as an excuse to eat more, and don’t use the fact you are on a diet as an excuse to stop exercising.
Why Mediterranean-style food?
The recipes you’ll find in this series are based on a Mediterranean-style diet, which is a way of eating that is rich in healthy natural fats, nuts and fish, as well as vegetables and legumes, which are packed with disease-fighting nutrients.
Because it is tasty and varied, it is far easier to stick to than more restrictive diets. You don’t eliminate lots of food groups, plus it is extremely filling, thanks to highish levels of natural fat, protein and fibre in the diet.
The recipes in this series are designed to be proportionally high in protein to help maintain muscle mass and stop your metabolic rate from crashing as you lose weight. This should mean you will find it much easier to keep the weight off.
A Mediterranean diet doesn’t just taste great, there is solid scientific evidence that eating like this will cut the risk of heart disease, cancer, type 2 diabetes, depression and dementia. Even if you only take up this way of eating later in middle age, studies show you can increase your life expectancy.
Two meals or three?
On your 800 calorie ‘fast days’, whether you are sticking to 800 calories every day or for just two days a week, many people find it easier to simply skip one meal and eat two meals and a small snack rather than three. It is often easiest to skip breakfast, or merge it with lunch as ‘brunch’, then have another meal later in the day.
Studies show it is better to eat most of your calories early. That’s because your body is much better at handling sugar and fat in the morning than in the evening when it is getting ready to close down for the night and will not appreciate being forced to re-start the complex process of digestion.
What about bread, rice and pasta?
The recipes in this series are lower in carbohydrate than you might be used to. I’ve avoided sugar and refined flour, and even bread, potatoes and rice in many cases.
This is because cutting back on starchy carbs will help persuade your body to switch from using sugars to burning fats for fuel and the best way to do this is through fasting, and keeping your carbohydrate intake low.
The Fast 800 is a mildly ketogenic diet, where you are eating a much higher ratio of fat and protein to carbs than you normally would, especially during the rapid weight-loss phase.
The term ‘ketogenic’ is one you may have heard before. As your body switches from burning sugar to burning fat, it produces substances called keto bodies, which will help suppress your appetite.
Rapid weight loss used to be called ‘crash dieting’ but recent research shows it can be safe and sustainable — people who lose weight quickly are more likely to keep it off.
Cautions and exclusions
You can stay in this fast-track phase for up to 12 weeks, but if you have any medical problems check with your GP before changing your diet. This diet is not suitable for the under-18s, if you’re breastfeeding, pregnant or undergoing fertility treatment.
Nor is it for those who are underweight, have an eating disorder, psychiatric disorder, had recent heart problems or uncontrolled heart disease or high blood pressure. Check with a doctor if you are unwell or recovering from significant surgery, have diabetes, retinopathy or epilepsy or are on certain medications.
The Fast 800 by Michael Mosley (Short Books, £8.99). To buy a copy for £6.74 (25 per cent discount) go to the Mail