High fibre food on table

Weight loss for better health

A personal trainer and nutritionist in the palm of your hand, ready when you are to support long-term weight loss

7-day trial

Join today!

What is The Fast 800?

A nutrition and lifestyle programme to activate your body’s natural ability to burn fat rapidly and facilitate your journey to long-term, sustainable weight loss

Developed by nutritionists and doctors, including Dr Michael Mosley, following the latest science. The Fast 800 is an independently validated programme designed to kick-start your body’s own weight loss mechanisms and help you lose weight quickly, improve your metabolic health and live longer.

Our step-by-step programme is simple to follow. It will help you flip your metabolic switch and burn through fat stores, restoring your body to health.

100k lives changed since 2018
6kg lost on avg in 12wks
8.6kg lost on avg in 12mths

What our members say

Over 100,000 members have turned their health around with The Fast 800 Programme

7-day free trial

Join today!

I wore my dream dress

"The Fast 800 is the only diet I've done that’s given me the knowledge to help me understand my body. I've reached my goal weight but I still follow this way of eating, it's so flexible and enjoyable."



Thanks to this style of eating!

I haven't felt this great in years

"The Med-style way of eating just works so well, as does 16:8 TRE. I am stronger, less anxious and generally happier."



So many health benefits!

I feel so proud

"My proudest achievement whilst on the plan was finding out that my HbA1c results had gone from 9.8% down to 5.4% over the 12 weeks."



I'm out of the pre-diabetes range!

Structure, the key to progress

“I lost 26 kilos in 24 weeks! Before trying The Fast 800, I had no structure to my meals. Thanks to the programme, following The Very Fast 800 and then The New 5:2, I’ve lost 26kg.”



My mind is so much clearer

Losing weight tasted so good!

"If I can transform my health, anyone can. I didn’t think I would have the willpower but I would tell anyone in my position to be positive, and try it for themselves."



It is the best thing I have done in my life

Trust the process

"I wasn't one of the people who lost a lot of weight at the start of The Fast 800. I steadily lost a few pounds each week. By the end of the initial 12 weeks of The Fast 800 I had lost 32 pounds and 7.5 inches off my waist."


I am so glad I persisted!

What's included?

Meal plans and shopping lists

Exercise plans and training guides

Real support

Personalised meal plans to support three meals or two meals per day

Automated shopping lists

700+ tasty and simple recipes

Vegetarian and non-vegetarian options

Flexible recipes when cooking for others

Variable approaches to suit your lifestyle

Daily guided exercise plans (beginner to advanced)

Low impact workouts for those new to exercise

Exercise library including resistance training, HIIT workouts, yoga and stretching

Multiple progressive Pilates plans

All can be done in your living room and with no equipment

A thriving Community platform to connect with like-minded members

Access to online health coaches

Exclusive health coach content including videos and challenges

Access to our extensive and exclusive learning centre

Tools and trackers to manage your goals and progress

Meal plans and shopping lists

Exercise plans and training guides

Real support

What does it cost?*

12-week programme

( – select your currency when you sign up)

This gives you access to the 12-week programme plus one extra month of membership to The Fast 800. After that, your ongoing monthly membership is . You can cancel this monthly membership at any time. *This price structure is only available via the website.

Free 7-day trial

Start your personalised programme now with your first 7 days absolutely free

Sign-up today and receive immediate Programme access, to help you prepare. Your week one will start on:

Monday 11th December

Join today!

The food

Delicious meals to enjoy, not endure

All approaches of The Fast 800 incorporate low-carbohydrate, Mediterranean-style meals that keep you fuller for longer and promote rapid fat burning. Our meal plans are nutritionally balanced, include a variety of easy recipes and of course, taste great!

Low Carb Lasagne

  • Prep 15m
  • Cook 40m
  • Calories 379
  • Carbs 11g

Big Brekkie

  • Prep 5m
  • Cook 15m
  • Calories 707
  • Carbs 29.4g

Beef Stir Fry

  • Prep 10m
  • Cook 15m
  • Calories 307
  • Carbs 9.9g

Broccoli Cheddar Soup

  • Prep 10m
  • Cook 30m
  • Calories 374
  • Carbs 7.1g

Mozzarella Chicken

  • Prep 10m
  • Cook 45m
  • Calories 531
  • Carbs 10.6g

Teriyaki Salmon

  • Prep 10m
  • Cook 15m
  • Calories 563
  • Carbs 15.2g

Our three core approaches

Finding a programme that works for you is so important in maintaining a healthy lifestyle long-term

The Very Fast 800

Best for Rapid weight loss

A short-term kick-start to improve metabolic health until a healthy weight is achieved, or for up to 12 weeks. Keto variations are available.

The New 5:2

Best for Gradual weight loss

Regular intermittent fasting for an effective, gradual way to lose weight or keep it off long-term.

The Way of Life

Best for Long-term metabolic health

A long-term maintenance approach for weight management and improving metabolic health.

Dr Michael Mosley explains the biology behind weight loss

7-day trial

Join today!

The science behind The Fast 800

The biology behind weight loss

How your body burns energy

Your body runs on two different types of fuel: glucose (i.e. sugar) and fat. Your body only turns to major fat burning for fuel when glucose supplies (which are stored mainly in your muscles and liver in the form of glycogen) start to run down.

The glucose problem

Many of the foods we eat are high in carbohydrates, which contain more glucose. If you eat a lot of high carb snacks or food during the day, your body will be busy burning glucose, not your fat stores. When there’s more glucose in the body than can be used, it triggers fat storage.

The key to burning fat

Less carbs. By eating less carbohydrates, your body naturally has less glucose to burn.

Less calories. By consuming about 800 calories each day, your body can swiftly burn through your glycogen stores and start burning fat instead.

Less often. By eating less frequently, your body can remain in the fat burning zone for longer.

What to expect while following The Very Fast 800

Click on the timestamps to see how the typical body responds over 12 weeks to our most popular approach

7-day trial

Join today!

Blood sugar

You may see a stabilisation

How you feel

Less hungry, with more energy and motivation

Weight loss

Potential weight loss

Body fuel


What's happening?

The body is likely in ketosis, and is adapting well to using fat as fuel. Motivation to continue will increase as the scales start to shift. Weight loss will differ from person to person.

Blood sugar

You will see a stabilisation

How you feel

You may feel demotivated if experiencing a plateau

Weight loss

Potential weight loss, or stabilisation

Body fuel


What's happening?

Metabolic health is improving. Your body is using energy more effectively and is able to switch between glucose and fat for fuel. Weight loss may stall for a few weeks, which is normal as the body continues to adjust.

Blood sugar

You should see a stabilisation

How you feel

Sleeping well. Sustained energy and motivation

Weight loss

Sustainable weight loss

Body fuel


What's happening?

You're in a good routine and have sustained energy for exercise. Your metabolism switches between glucose and fat burning easily. You may see a return to stable weekly loss of around 1lb/0.5kg a week.

Blood sugar

You should see a stabilisation

How you feel

Strong and motivated to continue with your health goals

Weight loss

Overall, significant weight reduction

Body fuel


What's happening?

Your body can now use the energy from your food efficiently. Insulin sensitivity has improved, meaning less insulin is required to control blood sugar levels. Your health is on track and you can feel the difference!

7-day trial

Join today!

Typical results from The Fast 800

Based on data collected from 23,000 members

Weight loss

6kg 3 mths

Members following the online programme for at least three months lost 6kg

7.3kg BMI > 30

Members who started with obesity (BMI >30) lost 7.3kg after three months

Long term sustained weight loss

Waist circumference reduction

Improved blood sugar levels

Lower HbA1c levels

Frequently Asked Questions

Browse through our most commonly asked questions

7-day trial

Join today!

How much does the programme cost?

What's included in the Programme?

How does the free trial work?

Who should avoid a low calorie diet or fasting?

How much weight will I lose?

Can I re-start the 12-week Programme after I start?

When does Week 1 start? Why is there "prepare" time?

Why 800 calories?

Do I have to give up coffee, smoking or alcohol?

Still got questions? Please visit our full FAQ page here or contact us and we’ll get back to you!

7-day trial

Join today!

7-day free trial

Join today!
    Your Cart
    Your cart is emptyReturn to Shop