Skip to Content

Fast 800 Results – Week 2 (Complete Update)

I tested out the fast 800 diet because I wanted to lose weight quickly at the start of my weight loss journey and having done lots of research into the diet, it seemed like a good place to start.

I tracked everything on a daily basis, for accountability and so I can help to motivate fellow fast 800’ers who are just starting out.

Having learned what works and what doesn’t, I’ve put together weekly updates, including lots of tips and tricks which might help you as you progress through your own journey.

In this post, I’ll be taking you through my experience of week two on the fast 800 diet, along with weight and measurement facts and figures.

Important Info

Before I begin, it’s important to know that the information on this page is purely my own experience and I am not a health professional. A rapid weight loss diet isn’t suitable for everyone, especially if you have an existing health condition or history of an eating disorder. (For more information check the Fast 800 Medical Disclaimer Page).

Just to let you know some of the products on this page have Amazon Associates affiliate links. I only recommend products which I feel might be helpful for a particular topic. I may receive a small commission for the recommendation however, I only link to quality products and in most cases those, I have tried – for more information please see my privacy policy.

Fast 800 Week Two Weight Loss

I weighed and measured myself on day one and then again at the end of week two and found that by sticking to the fast 800 plan for two weeks I lost 10lb/4.5kg in weight and my waist measurement dropped by 9cm/3.5in.

Below are all of the figures and conversions in both metric and imperial:

MeasurementStarting figuresFigures at the end of week two
Weight13st 10lb/
13st 0lb/182lb/82.6kg
Weight loss so farN/A10lb/4.5kg
Waist measurement107cm/42in98cm/38.6in
Waist reductionN/A9cm/3.5in
BMI30.1 (obese) 28.5 (overweight)
Milestones metN/AHalf a stone lost in 8 days
Fast 800 method usedN/AThe Very Fast 800 (800 calories per day)
Time-restricted eating (TRE)N/A16-20 hours (4-8 hour eating window)
Carb/protein/fat macrosN/AAround 30g carbs/60g protein/49g Fat

Although rapid weight-loss diets are sometimes frowned upon, this rapid weight is what I need to stay motivated. Personally, losing 1-2lb a week for me isn’t motivating because I like to see instant results or I’ll get bored and give up.

Michael Mosley recently showcased the fast 800 diet in a show called ‘Lose a Stone in 21 Days’ and the results from the participants of the show were consistent with mine.

This new way of eating not only shifts the pounds, but the evidence of health benefits from various medical trials is becoming stronger over time.

What I Ate to Lose Weight in Week 2

The fast 800 book and the recipe books contain lots of recipes and these are really good for making sure you’re getting the right amount of nutrients.

Some people follow this to the letter, but some choose to follow their own plan based on the principles of the diet.

I like to cook, so I do a mixture of both my own recipes and those from the books, which I tweak to my taste. If you like to know the full details, then here’s what I had on week two:

DayFood eatenCalories Kcal
Monday lunchGreek yogurt, blackberries & milled flaxseed & one scoop of Huel in the afternoon450
Monday dinnerLemon & garlic roasted chicken thighs (from the book)357
Tuesday lunchChicken and bacon salad525
Tuesday dinnerHomemade chicken curry with cauliflower rice430
Wednesday lunchScrambled egg, smoked salmon and tomatoes plus one scoop of Huel in the afternoon302
Wednesday dinnerHomemade chicken curry with shredded sprouts & almonds529
Thursday lunchSmoked salmon and cream cheese salad234
Thursday dinnerGoats cheese frittata (from the book) with bacon & salad537
Friday lunchGoats cheese frittata (from the book) with salad345
Friday dinnerhalf a sirloin steak with mushroom pizzas & salad450
Saturday lunchGoats cheese frittata (from the book) with salad345
Saturday dinnerHomemade chicken curry489
Sunday lunchGreek yogurt, blackberries, milled flaxseed & pistachios308
Sunday dinnerHomemade low carb Chilli con Carne with cauliflower rice462

The images below show an example of a chicken curry portion and a smoked salmon and creme cheese salad as a lunch portion, both of which make up around 800 calories for the day.

I also include lots of green vegetables with each meal, these are usually a combination of:

  • Broccoli
  • Cabbage
  • Green beans
  • Sprouts
  • Spinich

I found that eating two larger meals rather than three smaller ones, definitely works for me, but this is really down to the individual and how your day is structured.

Meal Replacement Shakes

The founder of the diet, Michael Mosley recommends meal replacement shakes now and again for those days when time is an issue.

Depending on the shake you choose, they generally contain a high amount of added nutrients, but you need to make sure they’re not high in carbs.

Fast 800 have their own balanced shakes and soups which are higher in protein and low in carbs and you can buy these directly on the fast 800 website.

I trialed using Huel shakes this week as an afternoon boost so I didn’t feel so hungry, I used the black version which is high in protein and lower in carbs.

While it is helpful to have a shake now and again, I don’t think I’d use this option too often because you can’t beat the feeling of being filled with food, especially when your daily portions are already restricted.

Changes in Week 2 of the Fast 800 Diet

Week two on the fast 800 diet is definitely easier than week one, for the following reasons:

  • Keto flu (caused by a low carb diet) generally goes away after the first week.
  • Your body gets used to smaller meals and less calories per day.
  • You have more enery as things settle, even when you’re fasting.
  • Food preparation gets easier, especially if you’ve been making and freezing extra portions.
  • You start to understand what works and what doesn’t and you can ajust your eating accordingly.

Personally, I felt a million times better in week two, and my energy levels were so much higher than before. I could see the results which motivated me to push on through the tough days.

I even had comments from people (who I’d not told about my diet) after only one week on the plan, saying how I looked like I’d lost lots of weight.

Although I’d already lost half a stone at this point, I think it was probably more noticeable because I’d lost a lot of bloating by cutting out sugar and carbs.


I’m not going to lie, the cravings can be tough on this diet and there are moments where you just want to crack and eat a sandwich or a pile of chips.

This is to be expected in the early days because your body is probably used to running on sugars found in carbs and you’re used to a much larger calorie intake per day than 800kcal.

Cravings do get easier as time goes by, especially if you eat filling foods such as high protein foods and high fiber veg, nuts, and seeds.

The best way to deal with cravings is by making sure you have like-for-like foods, for example, if you love pizza, a flat mushroom topped with tomato and mozzarella makes a great replacement.

Below are some other useful replacements depending on your tastes:

FoodHealthy replacement
Full English Fried BreakfastBacon, high meat sausage, egg, mushroom, tomato (no bread, beans, or potato)
Ice-creamMix frozen berries in greek yogurt & blend
White riceCauliflower rice (or brown rice but not on fast days)
PastaCourgetti Spaghetti (or brown pasta but not on fast days)
Mashed potatoMashed cauliflower (or carrot, swede, or squash better for non-fast days as higher in carbs)
Indian foodHomemade curry dishes are generally low in carbs (without rice or bread)
Chinese foodHomemade stir-fries are generally low in carbs (without rice or noodles)
Chips/friesCeleriac chips tossed in olive oil are much lower in carbs
High sugar fruits (bananas, tropical, etc)Berries, apples, and pears are better options (used sparingly)
Sausages/burgers (with added carbs)Choose high meat, gluten-free versions with no added rusk (bread)
ChocolateVery high cocoa content lower-carb dark chocolate (small piece on non-fast days)

Staying in ketosis

If you’ve been tracking your carbs and you’re keeping your daily carb intake under 50g per day (ideally lower), then chances are in week two you’ll be in a mild to moderate state of ketosis.

This means you will be burning stored fat more efficiently, which should speed up your weight loss.

You can check if you’re in ketosis by using a simple and inexpensive urine stick that shows the level of ketosis from none through to high.

I recommend and use the keto sticks available in the following Amazon link:

Ascensia Ketostix Reagent Strips (Ketone)

In week two you should see the reading getting darker and it will probably be in the mid-range.

I check every week to make sure I’ve not slipped and I’ve been in a moderate to high state of ketosis permanently from around day three of the diet. I’ve achieved this by setting a target of under 30g of carbs per day.

It’s recommended that you only stay in ketosis for a maximum of 12 weeks, although some people do go for longer.

Time Restricted Eating (TRE)

If you’re using TRE as part of the fast 800 plan, then you’ll probably find that it starts to get easier in the second week.

TRE is a bit like working out, in that the more you do it the easier it gets to do longer periods and this works well to help boost the effects of the fast 800 plan.

In week two, I found it easy to do an 16-20 hour fast each day and by shortening my eating window I felt fuller for longer.

Weirdly, the longer I fast the more alert and productive I get, compared to sluggish and exhausted pre-diet.

If you fancy giving TRE a try, start low at about 12 hours and work your way up. It’s really helpful to use a fasting tracker app too, so you don’t have to keep working out your times.

Tips for Getting Through Week 2 on the Fast 800 Diet

Here are some of the main things that I learned in the second week of the fast 800 diet, which you might find helpful:

  • Don’t worry if you have a few days where the scales go up or maintain for a few days, this is normal and you will lose weight if you stick to the plan.
  • You will have days where you want to give up, but try to push through because this diet really works.
  • Keep freezing extra portions to make food prep easier on busy days.
  • Use lots of spices and flavors to make your food more exciting.
  • Eat plenty of filling low carb veg and protein to keep you fuller for longer.

Key Takeaways

Navigating through the second week of my Fast 800 diet journey, I witnessed tangible results, not only in terms of weight loss and waist reduction but also in the efficacy of this low-calorie, potentially ketogenic, and time-restricted eating plan. The journey, albeit sprinkled with challenges like managing cravings and adapting to smaller meal portions, was also punctuated with victories, such as noticeable physical changes and enhanced energy levels. My meticulous tracking, strategic meal planning, and utilization of resources like meal replacement shakes and low-carb alternatives not only facilitated my adherence to the diet but also provided a framework that could assist and motivate others on a similar path. I found that while the Fast 800 diet can be demanding, its results can be significantly rewarding and perceptible even within a short timeframe.

Related Articles

For more information on what the fast 800 diet is and how to do it, take a look at the articles below:

The Fast 800 Diet – Review & Week By Week Weight Loss Updates

Fast 800 Results – Week 1 (With Tips and Food Ideas)