The 2-Day Diet

The 2-Day Diet is a clinically proven and easy-to-follow intermittent diet that can help you lose weight and become healthier. Developed by acclaimed Prevent Breast Cancer scientists, Dr Michelle Harvie and Professor Tony Howell, it is a revolutionary approach to weight loss which calls for just two days a week of dieting (restricted days), rather than counting calories or skipping meals.

Unlike other 5:2 diets, there are only a few simple rules to follow on the diet days – low in carbohydrates (including low-carb fruit and vegetables) but high in protein and healthy fats. This means that the two ‘restricted’ days will leave dieters feeling full and satisfied, rather than battling cravings. It is suggested to do your two days of dieting together. For the rest of the week, a balanced Mediterranean-style diet should be followed.

To reap the full benefits of the diet, on the ‘unrestricted’ days you should still be eating healthily, but you won’t have to drastically cut your calories or feel as if you’re depriving yourself of food as you would on other diets.

Diet & Breast Cancer

Being overweight and gaining weight over adult life can increase the risk of developing breast cancer. The average woman in the UK gains a stone in weight over their adult life. This increases risk of breast cancer by about 20% whilst gaining 1 and ½ stone increases risk by 60% and 3 stone doubles risk.

If you are someone who has already gained weight, you will be interested to know that weight loss seems to help reduce this extra risk. Prevent Breast Cancer was one of the first research groups to find that weight loss can reduce the risk of breast cancer. In our study of 34,000 women modest weight loss i.e. losing 10 pounds of weight reduced risk by 25-40%.


Benefits of the diet after breast cancer diagnosis and treatment

Many people with breast cancer have problems with their weight. For some, these can be long-standing problems, or they may be because of weight gained during treatment. Typically, three out of four women with breast cancer put on weight during treatment, including those who were previously a healthy weight. This happens with many different cancer treatments, as people can become less active and may find themselves eating more as their routine has changed or they could be comfort eating and have an increased appetite.

Being a healthy weight and doing regular exercise can increase your sense of well-being, boost energy levels and improve your mood. There is some evidence that it may also decrease the risk of cancer recurrence because it lowers levels of cancer promoting hormones. It may also reduce the risk of other health problems such as heart disease, stroke, dementia, diabetes and osteoporosis.


Restrictive and Unrestrictive days

Here you can find a brief overview of what you are and are not allowed to eat and drink on restrictive and unrestrictive days. To find out more, purchase The 2-Day Diet Book here.

Restrictive days

It’s important to drink plenty on your ‘restricted days’ – we recommend you drink at least 8 glasses of fluid each day. This helps you to feel full and helps prevent constipation.

Your 8 drinks can include water, tea, coffee, green tea, herbal teas, sugar-free, no added sugar or diet squash and fizzy drinks.

We often mistake thirst for hunger, and so if you really fancy something to eat, try having a large drink first and see if your cravings go away. There is no need to avoid drinks containing caffeine, for example tea and coffee. Some research shows these drinks can be beneficial for your health.


Drink to avoid

  • Alcohol
  • Adding sugar to drinks
  • Regular fizzy drinks which contain sugar
  • Fruit juice or shop bought smoothies
  • Drinking chocolate (can have cocoa sweetened with sweetener)
  • Malted milk drinks (e.g. Horlicks, Ovaltine) including low fat versions
  • Flavoured water which contains sugar (check the label)


Food to avoid

  • Bread, or food containing bread such as breaded fish
  • Breakfast cereals including porridge oats
  • Pasta, or pasta products such as lasagne, spaghetti in tomato sauce & ravioli
  • Rice, or rice products such as risotto, rice pudding & sushi
  • Potatoes, or potato products such as fish cakes, mashed potato, chips & waffles
  • Crackers, crisp breads and rice cakes
  • Sugar and foods with added sugar: e.g. cakes biscuits, fizzy drinks, honey, sweets & chocolate (you can use sweeteners)
  • Flour or foods containing flour such as white sauces


Unrestricted days

It is recommended to follow a balanced Mediterranean-style diet on your unrestricted days, this includes wholegrains, nuts, oily fish and plenty of colourful fruits and vegetables, plus the use of healthy fats like olive oil.

Carbohydrate foods give us energy and are often accused of making people gain weight. This is quite unfair – by themselves carbohydrate foods are quite low in calories, but we tend to make them higher by adding fat to them, for example by spreading butter thickly on toast.

You should choose wholegrain carbohydrates whenever possible. These have more fibre and nutrients than white versions and they help keep your bowels healthy and limit constipation.

Try to cut down on sugar and sugary snacks such as sweets, cakes and biscuits. These give us extra calories with few nutrients and because they are quickly digested, they often leave us craving more! White refined carbohydrates and sugary foods make the body produce more insulin which can increase the risk of developing cancer, heart disease, diabetes, and dementia.


The 2-Day Diet Book

You can purchase one of the official books written by Dr Michelle Harvie and Professor Tony Howell from the Prevent Breast Cancer shop here. What’s even better, all proceeds are donated to our charity.

Since the publication of the books, there have been a few adaptations to the diet, including portion sizes. For the most up to date information, alongside purchasing the book, click here to download The 2-Day Diet Booklet.


There are three books related to the The 2-Day Diet:

  • The 2-Day Diet Book is the original, clinically proven intermittent diet.
  • The 2-Day Diet Quick and Easy Edition is a simplified edition, adapted by acclaimed scientists Dr Michelle Harvie and Prof Tony Howell. With clear, safe and simple guidance, plus meal planners and delicious recipes, this unique way of eating means you can enjoy your food and stop worrying about your weight for good.
  • The 2-Day Diet Cookbook shares 65 delicious, healthy recipes for every day of the week, with ideas for both restricted and unrestricted days. With nutritionally balanced, easy-to-prepare and delicious recipes like these, along with tips, meal plans and a quick-reference guide to what to eat, The 2-Day Diet Cookbook shows you how to love food, lose weight and keep it off.

The 2-Day Diet Club

The 2-Day Diet Club is a Facebook group for those following the diet to gain and share tips, tricks, motivation, simplified recipes, and comradery. Find the private group by searching The 2 Day Diet Club on Facebook or clicking here.


The 2-Day Diet

If you have any questions about the diet, books or club, fill in the form below and a member of the team will be in touch.