Fasted FASTED

5:2 Diet Plan

The 5:2 diet is five days of normal eating and two days a week of 500 calories for women or 600 for men — the figures Michael Mosley and Mimi Spencer published in The Fast Diet in 2013. Keep the two low days apart, eat normally on the other five, and set your start date, low days and meal times below: the planner lays out the week, prints it and puts the low days in your calendar.

Nothing about 5:2 is complicated except remembering it. The rule is a sentence; the week it describes is where people slip, usually on the second low day, usually because a Thursday turned into a dinner. So this page does the one thing a rule cannot: it turns your two days into dates, your meal times into marks on a clock, and the whole week into something you can pin up or subscribe to.

Check with a clinician first. Do not start 5:2 if you are pregnant or breastfeeding, under 18, or have ever had an eating disorder. If you have diabetes or take insulin or any other medicine that lowers blood sugar, talk to your clinician before your first low day: a 500 kcal day changes what a fixed dose does. Stop and eat if you feel faint, shaky or confused.

Your week

Plan your 5:2 week

Low-day allowance
Your two low days

Pick two. Tap a day on the clock to swap it in.

Mon 5 Tue 6 Wed 7 Thu 8 Fri 9 Sat 10 Sun 11

Tap a day to change it.

  1. Mon5 Oct Low dayUp to 500 kcal, eaten at 08:00 and 19:00
  2. Tue6 Oct Normal dayEat normally
  3. Wed7 Oct Normal dayEat normally
  4. Thu8 Oct Low dayUp to 500 kcal, eaten at 08:00 and 19:00
  5. Fri9 Oct Normal dayEat normally
  6. Sat10 Oct Normal dayEat normally
  7. Sun11 Oct Normal dayEat normally
Low days
Mon and Thu
Low-day limit
500 kcal
Normal days
5
Days between
2

Every time here is a default until you change it, not a recommendation.

Take the plan with you

A plan on a web page is one you have to come back to. These two you keep: a sheet for the fridge and a calendar file for your phone. The file carries 4 weeks of days from your start date and refreshes every 24 hours, so a calendar that subscribes to its address never runs out.

Add to calendar (.ics) Print the week Quiet calendar version

If other people can see your calendar

Use the quiet version. It titles each day with plain words or the hours alone, and says nothing about fasting, calories or food anywhere in the file.

Subscribe rather than download

In Google Calendar choose "From URL"; in Apple Calendar choose File → New Calendar Subscription. Paste this address:

Where it comes from

Where 5:2 comes from

Two days of eating very little a week was a research idea before it was a diet. In 2011 a team in Manchester led by Michelle Harvie published a six-month trial comparing two restricted days a week with an ordinary daily diet. In August 2012 the BBC broadcast Horizon: Eat, Fast and Live Longer, in which the doctor and journalist Michael Mosley tried several fasting schemes on himself and settled on two days a week. In January 2013 he and Mimi Spencer published The Fast Diet, which gave the pattern its name and its numbers.

The book's rules are short: on two days a week eat a quarter of your usual intake, which it rounds to 500 kcal for women and 600 for men; keep the two days apart; eat normally on the other five, without making up for the low days. It allows the allowance as one meal or two. In 2018 Mosley published The Fast 800, which raised the low-day figure to 800 kcal; the 500 and 600 on this page are the original book's, because they are what most people mean by 5:2.

One thing the book did not keep from the trial behind it: Harvie's restricted days were two in a row, not two apart, and ran at about 2,710 kJ — roughly 650 kcal. Neither placement has been shown to beat the other. The planner lets you put your days either way and says which you have chosen.

What the trials found

What the trials found about 5:2

Two randomised trials carry most of the weight. Both compared 5:2 with an ordinary way of eating less, and both found the same thing.

The trial usually cited for 5:2 put 107 premenopausal women with overweight or obesity on either two restricted days a week or a daily 25% cut for six months. The two groups lost about the same, with no significant difference between them: 6.4 kg against 5.6 kg. Its restricted days ran at about 2,710 kJ — roughly 650 kcal — and were two consecutive days, not the split the book later printed. Harvie MN et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. International Journal of Obesity, 2011;35(5):714-727.

A one-year trial gave 300 adults with obesity either 5:2 instructions or standard weight-loss advice. After a year the two groups had lost almost exactly the same — 1.9 kg against 1.8 kg — and the share of people still keeping to 5:2 fell from 74% at six weeks to 22% at one year. Hajek P et al. A randomised controlled trial of the 5:2 diet. PLOS ONE, 2021;16(11):e0258853.

Read together: 5:2 loses about what any other way of eating less loses, no more and no less, and what decides the result is whether you are still doing it in month six. That is the case for choosing your low days with care rather than taking the first two on offer.

What this page will not tell you

Three things this page will not claim

“5:2 loses more weight than an ordinary diet.”

Not in the trials that tested it. Six months and a year, two different teams, the same finding: about the same weight lost as eating a little less every day.

“You can eat whatever you like on the other five days.”

The book says eat normally, not freely, and the alternate-day trials found people tend to eat less than they are allowed on the days between rather than more. A plan that treats normal days as a reward undoes the low days.

“Your low days should be these two.”

Nobody has tested one pair of weekdays against another. Monday and Thursday are a default because they keep the weekend free; the right two are the ones with the least eating you cannot control.

The other named protocols

Each has its own planner, built the same way.

For the daily windows from 12:12 to 23:1, use the fasting schedule planner.

How the week is worked out

Two choices decide the week: the date it starts and the two days you eat less. Everything else is the published rule and arithmetic on it. The low-day allowance is the figure Michael Mosley and Mimi Spencer printed in The Fast Diet in 2013 — 500 kcal for women, 600 for men — and the page prints it as theirs, not as ours. The trial behind the book did something slightly different: Harvie's 2011 trial set its restricted days at about 2,710 kJ, which is roughly 650 kcal (2,710 divided by 4.184), and put them on two consecutive days, where the book says to keep them apart. The planner lets you place the days either way and says which you have chosen.

The week clock is the week drawn as a ring: seven slices from your start date, clockwise from the top, each slice one day of twenty-four hours. A normal day is painted as ordinary eating. A low day carries a thin line along its inside edge for the calorie limit and a mark for each meal at the time you set. The start date defaults to the next Monday; every time on the page is a default you can change, not a recommendation.

The calendar file publishes one all-day event on each low day, for four weeks from your start date or today, whichever is later, with your meal times in the note and nothing on the normal days. It re-reads every twenty-four hours when you subscribe to it. The quiet version titles each low day a light day and says nothing about food.

What is not worked out here is how much weight the plan will lose. The two largest trials found 5:2 lost about the same as ordinary calorie cutting, and no more, and this page prints both rather than a forecast.

Where this comes from

  1. 1. The Fast Diet (Mosley M, Spencer M), catalogue record — Short Books (UK) and Atria Books (US), 2013 — Open Library
  2. 2. Horizon: Eat, Fast and Live Longer — BBC Two, 2012
  3. 3. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women — Harvie et al., International Journal of Obesity, 2011 (PubMed)
  4. 4. A randomised controlled trial of the 5:2 diet — Hajek et al., PLOS ONE, 2021 (PubMed)
  5. 5. The Fast800 Diet (Mosley M), catalogue record — Atria Books, 2018 — Open Library
  6. 6. RFC 5545 — Internet Calendaring and Scheduling Core Object Specification (iCalendar) — Desruisseaux (ed.), IETF, 2009

Nothing on this site is medically reviewed — it cites its sources so you can check them. Read our editorial policy. Method last checked 28 September 2026.

A 5:2 week is simple to describe and easy to lose track of. The rule fits in a sentence; the week it describes does not stay in anybody's head past the first Thursday.

So this page ends with two things you keep rather than a page you have to come back to: a sheet with the week on it for the fridge, and a calendar file that puts each low day, with its meal times, into the calendar already on your phone.

Frequently Asked Questions

What is the 5:2 diet plan?
Five days a week of normal eating and two days of eating very little: 500 kcal for women and 600 for men, the figures Michael Mosley and Mimi Spencer published in The Fast Diet in 2013, after Mosley's 2012 BBC Horizon film made the idea famous. The two low days are not fasts in the strict sense — there is food on them, just not much — and "normal" on the other five means ordinary meals, not making up for the low days. Everything else, including which days and when you eat on them, is yours to choose, which is what the planner on this page is for.

How many calories can I eat on a 5:2 low day?
The book says 500 for women and 600 for men. The trial the book leans on used a different number: Harvie's 2011 trial set its restricted days at about 2,710 kJ, roughly 650 kcal, which was a quarter of what each woman needed. In 2018 Mosley raised it to 800 kcal in The Fast 800. None of these three numbers was shown to beat the others; the 500 and 600 on this page are the ones most people mean when they say 5:2, and the planner prints them as the book's figures rather than as a rule of ours.

Which days should my 5:2 low days be?
Any two that are not back to back is the book's rule, and Monday with Thursday is the pair most people start on because it leaves the weekend alone. The trial behind the book did the opposite and put its two low days in a row, so back-to-back days are not untested — they are just harder for most people. Pick the two days with the least eating you cannot control: no work lunch, no family dinner, no birthday. You can tap a day on the week clock to swap it in.

Should I eat one meal or two on a low day?
Either works; the allowance is the rule, not the number of meals. Splitting it into a small breakfast and a small evening meal leaves a long gap in the middle of the day, which many people find easier than going until evening on nothing. One meal suits people who would rather not start eating at all. The planner prints both ways: set a second meal time, or choose one meal only.

Does the 5:2 diet work better than ordinary dieting?
Not in the trials that have tested it. Harvie's six-month trial in 107 women found two restricted days a week lost about the same as a daily cut — 6.4 kg against 5.6 kg, with no significant difference. A one-year trial in 300 adults found 5:2 instructions and standard advice lost almost exactly the same, 1.9 kg against 1.8 kg, and that only 22% of the 5:2 group were still keeping to it after a year. The honest case for 5:2 is not that it beats a diet; it is that some people find two hard days easier than seven slightly hard ones.

Can I put my 5:2 low days in Google Calendar or Apple Calendar?
Yes. The calendar file on this page puts an all-day event on each low day for four weeks from your start date, with your meal times in the note, and nothing on normal days. Subscribe to its address rather than downloading it and the plan keeps rolling forward. If anyone else can see your calendar, use the quiet version: it calls each low day a light day and says nothing about food or calories.

Who should not do the 5:2 diet?
Anyone pregnant or breastfeeding, anyone under 18, and anyone with a current or past eating disorder should not start it. Anyone with diabetes, and anyone taking insulin or another medicine that lowers blood sugar, should not start it without their clinician adjusting the plan first, because a 500 kcal day changes what those doses do. If a low day leaves you faint, shaky or confused, eat.

Go deeper

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More Tools

Alternate-Day Fasting Schedule

Plan alternate-day fasting from your start date: 500 kcal or no-food fast days, your eating hours between, a two-week clock, a sheet and an .ics file.

Fasting Schedule Planner

Your eating window for six schedules from 12:12 to OMAD, on a week you can print and a calendar you can subscribe to. Pick the protocol and the hour you want to eat first; the times, the sheet and the .ics file follow.

Calorie Deficit Calculator

Calculate the right calorie deficit for your weight loss goal. See daily calories, weekly deficit, and time to reach your target weight.

Time the fasts Fasted does run

Fasted does not run a 5:2 week and never has: its catalogue is six daily windows from 12:12 to 23:1 and four longer fasts from 24 to 72 hours. The calendar file on this page is the half of 5:2 the app does not do.

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