Fast 800

Yes, I read about this last week: East London hospital to treat Type 2 Diabetes with protein shakes


This is an interesting article from the NHS website

From my experience, opinion is divided in the medical world, with some doctors recommending a total 3 day fast (whilst in hospital and being monitored, post chemo - I have a friend who did this, and felt she benefited, although its hard to know for sure). Other doctors think fasting will weaken your already weakened system and is a bad idea post chemo, or post recovery.

I’ve been someone with a life-long belief that fasting is not a sensible thing to do (in ayurvedic medicine there is a saying ‘you should only fast between meals, and you should always fast between meals’) as it weakens your system.
But, I’ve more recently changed my view completely and have personally reversed my own pre-diabetes through fasting (a few years ago now), and actually find it beneficial to my digestive system, immune system and overall health to fast for 24 hours occasionally.
I personally believe however that fasting should be done on days when you are able to rest (not completely but just not on days you have to work or be stressed or be really active).

Ultimately, everyone is different, and some people will find a short term very low calorie diet, will boost their health and weight loss and motivate them to continue more long term on a slightly less restrictive and more realistic calorie deficit. Other people are able to choose a reasonable daily deficit from day 1 and maintain that long term, producing steady weight loss results.
We all have different constitutions and psychological make-ups, and different methods will work for different people.

Just wanna say good luck @climbergirl ! I hope Huel and your new diet plan helps you improve your health. Keep us posted, it’ll be really good to know how you are getting on.


Thank you Christina

I’m a big believer in fasting for health and congrats reversing your pre-diabetes! I have family members with the condition and it’s something I’m keen to avoid! (Sadly can’t convince them of the potential benefits of fasting).


Losing weight to be within healthy weight range works for many people in reversing prediabetes. I know several people who this has worked for. Also lowers blood pressure for many.

It’s not necessarily about losing weight @hunzas
When I had pre-diabetes I was a perfect weight for my height, actually really slim.
It’s about reducing calorie intake enough to desensitise your body to the insulin response. Which fasting does really quickly, or dieting does also but a little more slowly.

Ah ok. All I know is that the losing weight aspect has worked for several peiple i know. Diabetes is more complex than I understand and also rising dramatically here and in USA.

My dad is diabetic but again not through usual way. He has never been overweight…in fact he is underweight. He has never been a drinker. Has had a reasonably good non junk diet all his life. Alas as a result of pancreatitis…cause not known.

1 Like

It’s usually a high sugar or high GI diet that causes type 2 diabetes, as (in really simple terms), the body loses its sensitivity to insulin so produces more and more and more every time you eat, this insulin resistance is termed ‘pre-diabetes’. Eventually the body’s ability to produce insulin fails due to this constant over-production, and that’s then type 2 diabetes.
There’s also other genetic and disease driven causes however - endocrine system disorders, hormonal imbalances, and yes pancreatitis.
The high sugar diet cause is the easiest and fastest to fix especially if caught early.
I’m guessing in your dad’s case, a fasting or low GI diet or low calorie diet isn’t going to reverse his condition?

Whilst I agree that you cutting to 800 thus creating a calorie deficit, you are not just doing this. You are eating 800 calories worth of food that is low in carbohydrate and your body deals with this differently to 800 calories worth of gummy bears.

I could argue that most ‘diets’ do not support dieters long term, that’s why so many pile the weight back on after they ‘come off’ e.g. weightwatchers or slimming world. I went to ww once, the focus seemed to be on eating as much foot as possible even if it was crap, eg. puffed wheat for breakfast. That is now how I eat or how I want to eat. The Fast 800 is mainly cutting out sugars and high carb foods such as potatoes, pasta etc, it’s also about portion size (a big downfall for me, Im a real greedy guts). Moving to 5:2 means you can introduce these back but fast for 2 days. For me, giving my body a rest feels good. Putting my body into a state of burning fat feels good and doesn’t seem to make me feel hungry.

I think Huel can be a good support to this plan as it fills you up and is quick to make.


BTW meant to say good luck Climbergirl, I hope it works for you and you get stronger and stronger :slight_smile:

Personally 800 calories of Huel for me is pretty easy to survive on for a day.
I couldn’t do that for more than one day in a row with any other kind of food.
I am fairly little however, and on a sedentary day only burn 1200 calories so its not a massive cut for me.
Regardless - its way easier maintaining a calorie deficit of Huel than a calorie deficit of any other food, in my experience

1 Like

Nope. He is now so underweight he can’t have a low calorie diet. His blood sugar is all over the place…he had his first ever diabetic coma in October. The readings maxxed Out his consumer bloodtester…

I’m sorry to hear that. I thought that was probably the case. When diabetes isn’t caused by being overweight or having a poor diet, it’s so much harder to treat. It also cannot be reversed.
It’s then just a case of managing it as best you can. Horrible disease to suffer from xx

I tried the 5:2 diet 2 years ago to combat 10lbs weight gain caused by a couple of months of steroid treatment. It really did work and reduced my appetite after the first couple of weeks. I was just about eating my own arms the first 2 weeks though. Really psychologically difficult!

I was aiming to reduce to 6:1 to maintain as it had benefits for my IBS and eosinophllic disease but, after about 5 weeks I started to become really ill on fast days - multiple fainting incidents and eventually a hospital visit. Turns out I have hypoglycemic episodes if I don’t eat every 3-4 hours. The cause is still unknown, I’ve been tested for diabetes and a lot of other things and they just don’t know why. So, not more fasting for me! Thankfully my weight had stabilised to my normal and healthy level in just those 5 weeks so that wasn’t an issue any more.

In summary, you don’t know if you’ll take to fasting unless you try. It does work but just be careful in case your body pushes back! It’s not for everyone.


So anyway, I’m nearing the end of day 2. Feeling pretty good, had a very mild headache but that’s gone now. Carrying on with my normal exercise routine so climbing yesterday and pole fitness this evening. Energy levels not too bad.

This definitely feels more like fasting rather than dieting, apparently 800kcals is low enough for your body to believe a fast is taking place. I’ll test tomorrow morning for ketones as this w.o.e. is supposed to trigger mild ketosis.

I was down 2.3lbs this morning, although likely to be mostly water weight.

Thanks @Foxykiwi hope you’re getting on okay!


I don’t think you need to necessarily stick to super low carb or a rigid Mediterranean diet, a vegan diet is pretty healthy (as long as its not packed full of processed vegan stuff).

I have a recipe for really yummy lentils that I make twice a week if you like, its delicious and really filling. That with some roasted vegetables is a good option. I’ve also got a good risotto recipe. Tofu with stir fried vegetables (use olive oil), guacamole and tomatoes on toast, bean chilli, homemade humus salad, none of these things are unhealthy. They might not fall under the banner of “Mediterranean diet”, but it’s the same concept: priority given to fresh veg and olive oil.

1 Like

Hi, Happy New Year.

Just reading your thread, and I’m in a similar situation. Following cancer treatment a number of years ago, I have been getting bigger.

It’s so inspiring to hear your I’m going to try again, I actually like Huel and have been using it on and off for years.

Thanks for inspiring me to try again.


How is everyone getting on ? I only started on Sunday and so am only on day 4. I have been having 900 calories of Huel a day rather than sticking strictly to 800 and starting to eat at 2pm. I have my glass of ACV first thing which I find keeps the hunger at bay.
So far lost 5.6 lbs…

@B7YEN hey! Sorry only just saw this message - how are you getting on? Treatment certainly takes it toll on the body but you got this!!

@Juke How’s it going? Grats on the weight loss!

I lost 7lbs in the first week then was a bit bored so started back with keto. I am intermittent fasting from 7.30pm to 10am, keeping carbs under 50g per day and about 70-80% calories from fat. Calories are naturally coming out at about 1100 - 1300 without ever feeling hungry, weight loss is pretty steady and body fat% falling as well!

1 Like

I’m attempting to spend a couple of weeks following a strict variation of the Fast 800 diet using 100% Huel. I’m 39, male, with a couple of stone to lose.

The Fast 800 diet recommends a low carb approach (not keto) and I notice that the new Black Edition of Huel has fairly similar macros to the official shake product sold on the Fast 800 website:

Fast 800 vegan vanilla shake

  • 370 calories
  • 43.9g protein
  • 16.1g fat
  • 11.2g carbs (5.8g as sugars)
  • 13.1g fibre

Huel Black Edition

  • 400 calories
  • 40g protein
  • 18g fat
  • 17g carbs (4.4g as sugars)
  • 6.6g fibre

I’d much rather use a product from Huel for this sort of thing, so I’ll be going with the Black Edition for this. I’ve been eating standard Huel for the majority of my breakfasts and lunches over the last year and have a lot of trust in the product and team from Huel.

I also plan to top up my vitamins and minerals with a quality supplement every other day, and to stay well hydrated.

Has anyone else tried something similar recently?


You of course won’t find anybody with long term experience with the black edition, as it was released just a week or so ago.

That said, I did 7 weeks of standard huel only (~210g per day, mainly pure UU) this summer. I calculated the vitamins and minerals lacking from what a full replacement low calorie diet-shake legally has to contain and chose supplements accordingly. Plus I recommend to add some salt from time to time, as it turned out to be too little for me. (Salt hunger showed me the way out of muscle symptoms.)

In week 7 I became a bit bored taste-wise and appetite-less, so afterwards I did 5 weeks of only 1-2 huel per day and the other meals with different shakes. Then again huel in decreasing amounts in combination with food in increasing amounts with a structured eating plan for 8 more weeks. Did all of this according to the optifast 52-plan, never heard of your plan before.

Did another 3 weeks of huel only as LCD this december for the last few kgs. Am done now.

1 Like