800 calories for everyone? Does that make sense

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• posted by Jeremy Fisher
  on 14 Jun 2020 at 11:37

  

  It doesn’t make sense to me why everyone is doing 800 calories a day when people are so different.

  I was thinking this while on my run today. I burnt over 800 calories on that run and so felt I deserved to eat a little more today! (And yes I am struggling a little (!!) – now on day 7!). I’m effectively on zero calories today.

  But compared with someone that never exercises I’m on way fewer calories than them this week.

  And what about the differences in people. Men, on average burn 2500 calories a day and women 2000. So men are 1700 calories in deficit and women just 1200. And then, if you’re a petite woman with a desk job, do no exercise and have a sedate lifestyle, then you’d need fewer calories a day (let’s say 1600) and so you are just 900 calories in deficit.

  If you’re a 6ft 5inch bodybuilder you’d burn way over 2500 calories in a day and are massively in deficit.

  I wonder if this is one of the reasons why some people report such different levels of weight loss here. They’re really not on the same diet at all! And perhaps why some people struggle much more than others on the diet.

  Perhaps the “800” is just for ease (rather than make everyone work out their right amount which is more complicated) and branding purposes – it is the Fast800 after all. Or perhaps I’m missing something.

• posted by Waitaminute
  on 14 Jun 2020 at 11:59

  

  Hi Jeremy,
  A lot of people on here, me included don’t count calories we stick to low carbs. It’s easier to lower your carb intake to 20g a day, by cutting out bread, rice, pasta, sugar etc ( all the nasties). Give it a try and see how you go. Oh and drink lots of water .
  😊🖐️

• posted by Waitaminute
  on 14 Jun 2020 at 12:08

  

  I forgot to mention you also need to eat full fat food rather than low fat and protein to help keep you full longer. 😊🖐️

• posted by DoubleDutch
  on 14 Jun 2020 at 15:42

  

  Hi Jeremy,
  As far as I kno, dr Mosley originally based his bloodsuger diet around 2 days ‘fasting’ a day. Since fasting can be severe, he changed this into 500 cals a day for females and 600 for men
  He later revised this to 800 for all because from his research, it didn’t influence the weightloss too much, and people could manage this for much longer. Hence, the fast 800 were you can do this every day for some time, depending goals, weight, etc.
  staying under 20 grams of carbs, will put you in fat burning mode, and in that case, is doesn’t matter how many cals you need, it will come from your own fat supply. So, the 800 seems to be chose as an amount what most people can handle, still enjoy their food and as a result, successful weightloss. I personally believe, the more you can manage to stay close to this 800, the better. The bigger your calorie deficit, the more comes from your fat supply. I agree, it’s weird on those days where you burn 3000 calories, and eat just 800, but simply put, this means 2800 cals deficit = over one third of a kilo of fat used to supply these 3000 calories you needed.

  For me, the ‘clean’ fast 800 ( staying on or around 20 grams of carbs, and 800 cals) has lead to fantastic weightloss, see my profile. However, if you don’t feel like measuring and weighing everything, or 800 is too hard, no one here will judge you. Your deficit will be a bit smaller and this might influence your pace in discarding weight, but it doesn’t matter. What matters is becoming healthy! I am struggling to stay under 800 myself right now, I’ve changed my tack and now aim for an avarage of 800. This works for me, but it may be different for each individual.

  Hope this helps 🙂
  DD

• posted by DoubleDutch
  on 14 Jun 2020 at 15:47

  

  My calculations are way off, 3000-800 should be 2200 of course. So after 4 days like this gone with more than a kilo of fat 🙂

• posted by DoubleDutch
  on 14 Jun 2020 at 16:08

  

  And yes, I agree with you, Jeremy, a person with a smaller deficit will discard slower than people with a high deficit Every kilo of fat has to be burned by your body and the more your body needs, the quicker it will be gone.
  I also feel like eating more when I’ve done some serieus workout, and sometimes i do allow myself to eat more. Listen to you body..

• posted by JGwen
  on 14 Jun 2020 at 17:36

  

  Hi Jeremy,
  You are right that at the simplest level, if your carb intake is low enough -> so that your insulin levels are low, -> so your body can use fat for fuel then calorie intake controls the rate at which the body uses up fat. – Each lb of fat = 3500 calories.

  However, in reality it is not that simple. –

  Our metabolic rate is dependant on our eating patterns, every time we have tried to diet by just calorie counting and ignoring carb levels we will have put our bodies into starvation mode and our body will have become more economical on the number of calories it needs. – Look at the research into the long term impact on metabolic rate of the program The Biggest Loser. – One of the long term successes with this WoE is Alliecat, who took up this way of eating 4 years ago, and had a substantial discard ( If my memory serves me right its over 100lbs) but to maintain that discard she was only able to increase calorie intake to 1400 a day when keeping carbs at the 20g level.

  Many of us who have been eating a high carb diet for years have a problem known as Insulin resistance, I think of that as my body having a hair trigger response to carbs. – Although I have been eating low carb for a couple of years now, its still not easy to stay in ketosis even with a target of 20g of carbs a day and an active lifestyle.

  Our gut bacteria change in response to our diet, while the bacteria which digest sugar does die off in response to a low carb diet, they are also able to multiply rapidly, so every time we step off the wagon they will multiply again.

  However, the biggest mistake people make is to focus on weight rather than body composition and fitness. . – When we eat a high carb diet our bodies store water to help process the sugars. – As soon as we reduce carb levels our bodies can release that water, and so there is a rapid weight loss for some at the start. But its not fat loss.

  Our hormone levels are interconnected signalling systems, so when insulin levels are high it blocks growth hormone and its growth hormone which controls things like the density of bones, and strength of muscles. – Therefore low insulin levels can result in an increase in weight but a loss in inches as fat is burned but bones and muscles become stronger.

• posted by DoubleDutch
  on 14 Jun 2020 at 17:54

  

  Thanks JGwen!
  I’m now reading about maintenance and I’ve read your posts with attention. You do thorough research and I trust your information! I might ask some maintenance questions at a later stage, great to have you still around! 🙂
  DD

• posted by Jeremy Fisher
  on 14 Jun 2020 at 18:26

  

  Thanks for the reply JGwen. That’s interesting and useful.

  But it doesn’t really answer my question.

  The programme is the Fast800. Why 800 for everyone? That just doesn’t seem right. In fact your points make it even more relevant – there are even more factors to consider than in my original post.

• posted by Britta
  on 14 Jun 2020 at 19:37

  

  Hi Jeremy

  I don’t know how many different diets you have been on, but in terms of individualised recommendations there’s not that much difference between these ‘off the shelf’ diets. Some offer different guidelines for men and women, few offer different guidelines for different ages, even fewer for different ethnicities and when you get into blood-types, genes, well then it just starts to get a bit silly. If you want a diet that is properly fitted to your individual metabolic profile, you need a whole heap of tests, measurements etc and even then it isn’t an exact science. There are not enough randomised trials, particularly not enough sex disaggregated data to make generalised recommendations like that. Men and women are different yes, but so are women and women and men and men and the levels of uncertainty that you end up with are too great. So yes, men tend to burn more calories, but there isn’t a simple algorithm that can tell you by how much. So in that sense 800 for all isn’t right for everyone anymore than ‘5 a day’ is or ‘6g of salt’ or a ‘bmi between 18.5 and 24.9’ or ‘10.000 steps’ is right for everyone. But it still works for most.

• posted by Jeremy Fisher
  on 15 Jun 2020 at 06:53

  

  Hi Britta.

  I absolutely agree with your points that everyone is different. However there are some things which are very easy measure and adjust for.

  Here is an excellent article which shows research into average calories burned per day. https://fitfolk.com/average-calories-burned-per-day-men-women/

  So… The median calories burned by men is 3076 and women 2365. This makes it completely crazy to have the same 800 for both men and women. These are not the same diets. Men will lose weight more quickly, which does reflect research (https://www.livescience.com/63324-men-women-weight-loss-difference.html), but are also likely to find it harder as their deficit is greater.

  But, as you see, the graph also shows the difference between everyone is huge as well. Taking out the extreme people – at the low end women burn about 2000 calories a day and at the high end 3000 calories a day. Although there can be other factors, the mostly likely reason for the difference is how active people are, and their current weight (the heavier the more calories burnt). So again, a 3000 a day woman on 800 calories will lose weight very quickly. A 2000 a day woman, much more slowly.

  That really wouldn’t be hard to estimate. And let’s be honest it’s easy to know how active you are to work this out. I have a very sedentary job, and general lifestyle. Yet I bodybuild, and so have a good muscle mass, and run regularly – so on balance I’m probably about average.

  And yes. Every individual is different, but the main factors are very easy to work out. So that still leaves me wondering why Michael will have stuck to 800 for everyone when it just doesn’t make sense.

• posted by WindyJulz
  on 15 Jun 2020 at 07:54

  

  JeremyF – I’m not disagreeing with anything you are saying, but i think you are over thinking it.
  The 800 phase is not designed to be forever nor is it designed (I dont think) for elite athletes). It is an optional phase to kick start the process and for very quick weightloss. (it also assumes you ahve weight to loose). It is not designed around how many calories you need or burn, as in theory you go into fat burning mode and so calories in are not relevant as you will use your fat stores therefore an extra 200 or 500 calories should have no effect on energy levels. It uses fasting principles and recognises that 800 is just as effective as 500 but easier to sustain. It is designed to be for 2-12 weeks. Exercise is encouraged but not essential. Again as you are burning fat not carbs you should have plenty energy for moderate exercise. It is not just about the calories in either – it is about the right calories from good fats and proteins and low carb.

  Based on that, I read it as 800 applies to everyone as it is an achievable number of calories given the med style food choices, to allow for 2-3 meals a day, to allow for a comfortable lifestyle whilst you go into fat burning, to ensure that everyone will loose weight no matter the lifestyle. It is simple, easy to follow and clear. OF course, given the variances you describe people will loose at differing rates…..but almost everyone will loose adn loose fairly quickly, compared to other ‘diets’.

  Does that help?

• posted by Jeremy Fisher
  on 15 Jun 2020 at 11:27

  

  WindyJulz – I suspect you’re right that that 800 has been designed for simplicity. I’m just not sure it does offer everyone the same comfort. Someone with a very active lifestyle is likely to struggle a lot more on 800 calories than someone who is small, female and has a sedate lifestyle. They’re simply need more calories during the day and they’re body will find it harder to cope.

  You say the following “in theory you go into fat burning mode and so calories in are not relevant”. That’s simply not true. If you eat a lot of protein and fat (and low carbs) they still get converted into fat by the body. You will put on weight. Eat 5000 cals a day of anything and weight will go up. If you only eat 800 calories of anything and everyone’s weight will go down. And yes perhaps low carb diets have the advantage of ketosis, but calories, of course, play a part. Also, someone who burns more calories in a day because of an active lifestyle or exercise will lose weight more quickly. Men do lose weight more quickly on diets than women (on average).

  ” 800 is just as effective as 500 but easier to sustain.” Yes it’s just as effective in terms of getting into ketosis, but you will lose more weight if you eat 500 calories a day than 800. Michael makes it clear in his book that he only moved to 800 because it was more manageable for people and that’s key to success long term.

  Low carb diets tend to be more successful in the long term than other diets. There’s lots of evidence for that: https://www.healthline.com/nutrition/23-studies-on-low-carb-and-low-fat-diets.

  The reasons are less clear. Perhaps part of that is burning fat. But a lot of it is that they help to control hunger and so people feel less inclined to eat a lot and can stick to it more easily. Ultimately calories in vs out is the most important factor in any diet and can’t be ignored. And Michael hasn’t ignored that either. The book is called the Fast800 after all!

  So I come back to: 800 for everyone does not make sense. Some should be on fewer and some on more.

• posted by Jeremy Fisher
  on 15 Jun 2020 at 11:52

  

  WindyJulz – I agree with you that 800 calories a day is probably just there for simplicity, and that people will lose weight at different weights for a variety of reasons.

  Do be careful though. Calories are always relevant on diets. When you say “in theory you go into fat burning mode and so calories in are not relevant “. Even in fat burning mode, those eating more calories lose less weight than those eating fewer. And those that burn more calories a day such as men, people who are heavier, and those with active lifestyles will also lose weight more quickly.

  It’s interesting that you say that ” 200 or 500 calories should have no effect on energy levels.” I do see what you mean by this. In theory we’re running on fat reserves so should have enough energy from that whoever we are – we should just burn more fat for our energy. Does it work really work like that though? Perhaps the body is best suited to getting some energy from your diet and some from fat stores, and people who burn a lot of calories each day struggle on the diet more than those who burn fewer. I don’t know about this one.

• posted by JGwen
  on 15 Jun 2020 at 12:45

  

  Hi JeremyF.

  I think that you may be getting caught up in the old myth of calories in / calories out method of weight loss. –

  I think for many of us the Fast 800 book was attractive because of the cover promising a dramatic weight loss in 8 weeks. – For many of us who had a lot of weight to discard as we came up towards the 8 weeks the question was what now, I am really pleased with the program but I still have fat I want to get rid of, I am not ready to go into maintenance. The benefit is that it has started many of us on a journey on understanding how our bodies work and we end up reading the research and watching podcasts by people who explain how our bodies work.

  I would suggest if you are into technical articles, the book why we get fat and what to do about it, is a resource that would answer all your questions. = If you prefer videos which include references to research papers then I would suggest Dr Fungs work. https://www.youtube.com/watch?v=tIuj-oMN-Fk is a good one with a section on why the calories in / out doesn’t work for weight loss. Or this is a longer podcast with more research studies listed https://www.youtube.com/watch?v=7nJgHBbEgsE

• posted by Jeremy Fisher
  on 15 Jun 2020 at 14:16

  

  JGwen – I loved the first video. Huge thanks for that – very interesting. And motivating too! Makes me convinced I’m doing the right thing!

  However….(sorry!!)

  Dr Fung doesn’t say calories in vs calories out doesn’t work for losing weight in the short term. In fact the whole video actually says that IS the basis for weight loss. He says that if you do it in the traditional way your metabolic rate goes down and you burn fewer calories each day, so you need fewer calories each day and that’s the problem with a traditional diet and why people put the weight back on.

  Fasting does not reduce your metabolic rate however and is why people do better on a fasting programme, because they continue burning more calories each day in the long term.

  And so that doesn’t answer my question. Why is everyone 800 calories per day? It still doesn’t make sense as 800 is so completely different for each individual in terms of calorie deficit. Or to put it another way… 800 calories could be considered a fast for one person, but 1300 could be considered a fast for another if that person naturally burns an extra 500 calories a day as the net deficit for both people is the same.
  e.g. John burns 3000 calories a day and eats 1300 calories. He’s 1700 deficient.
  Chris burns 2500 calories a day and eats 800 calories. He’s also 1700 deficient.
  If both enter ketosis then surely that’s fine. But perhaps John doesn’t enter ketosis because you never can if you eat above 800 calories.

  Sorry about the details here, but hopefully you understand my point.

• posted by DoubleDutch
  on 15 Jun 2020 at 19:59

  

  Hi Jeremy,
  What do you mean by “But perhaps John doesn’t enter ketosis because you never can if you eat above 800 calories.”
  Most people on keto are eating WAY over 800. Imho, it’s quite possible to enter / stay in ketosis and eat 5000 calories. As long as one stays under 20 grams of carbs, or whatever your threshold may be.
  DD

• posted by Jeremy Fisher
  on 15 Jun 2020 at 20:29

  

  Okay. Thanks DD. So ketosis is all about low carbs.
  And low calories is about losing weight – both together burn fat fastest.

  PS Your earlier post made complete sense to me. Thanks for your thoughts.

• posted by Jeremy Fisher
  on 15 Jun 2020 at 20:33

  

  Okay. Thanks DD. So ketosis is all about low carbs.
  And low calories is about losing weight – both together burn fat fastest.

  PS Your earlier post made complete sense to me. Thanks for your thoughts.

  And a huge well done for your success. Amazing!

• posted by JGwen
  on 16 Jun 2020 at 06:10

  

  Hi Jeremy,
  The principle behind the book is a short sharp weight loss program and then people would continue at a slower pace.

  When research is carried out on fasting for some reason they categorise fasting as being 500 or less calories a day. – But if my memory serves me, I believe you will find in the Fast 800 book the Dr MM decided that 500 calories a day would be difficult for people to stick with for 8 weeks. So he set the limit at 800 calories.

  I think you have subsequently picked up on the issue. – Its not about the calories its about the insulin levels. – If you keep insulin low your body can first of all access the “fridge” and then move on to accessing the “freezer” stores of fat.

  The rapid weight loss at the start of this program is not fat loss. – Its water loss. Our bodies need to store water to help it process the carbs, once you cut out the carbs that water is released. This can cause what is known as keto flu in the first few days of reducing carb intake. – Its caused by our kidneys releasing electrolytes when releasing the stored water. Low levels of electrolytes can feel like flu. The solution is to increase salt intake. You will find that eating low carbs does increase your need for salt anyway. Salt is often included in processed food and when you move to cooking from scratch your salt intake will reduce unless you take a supplement.

• posted by sunshine-girl
  on 16 Jun 2020 at 13:56

  

  If I can just go back to one of the original ideas behind the diet, the 800 calories was taken from the research by Prof Roy Taylor of Newcastle University. He worked with diabetics (and others) who were seriously obese and he was doing gastric surgery (bands and reducing stomach size). These people cannot eat solid food after the op and were put on a liquid diet which amounted to 600 calories as a very strict reduction in food intake so they would lose the weight quickly and also the stomach couldn’t take any more than that. Still with me… Okay. Suddenly Prof T notices that the diabetics are no longer needing to control their blood glucose with drugs and the strictness of the diet had reduced the need. Many of these diabetics no longer had diabetes at all. Don’t forget these people are in hospital and are being carefully supervised so they don’t get ill from the very low calories. Along comes Dr Mosley who has just discovered he is type 2 and has heard of Prof Taylor and takes an interest in his work. Between the 2 of them they come up with a diet that mimicks the 600 cal but is not quite so severe and it turns out that 800 cals is the optimum level. Also, it has to be a diet that people at home can do and for it to be sustainable needed to use real food. Also, the liquid diet used by Prof T was scientifically measured and balanced to provide all the nutrients etc. We don’t use liquid diets because the ones on the market are not nutritionally balanced and contain sugars etc (not all but most). Now more science. It was found that on just 600 cals (or 800 in Dr M’s diet) the body is shocked into shedding the most difficult fat of all. The hidden fat around our organs (visceral fat) and especially for diabetics, around the liver and pancreas. This dissolving of the visceral fat, in some cases, kick starts the pancreas to start producing insulin again, and the liver to stop pumping glycogen (a glucose) into the blood. Thereby reversing diabetes.

  Now my doctor still thinks it would be a miracle but has to admit that the diet works for me even though I have not reversed diabetes as I have had it for a long time. This works best with people newly diagnosed or not had it for more than 2 to 5 years. I personally have reduced insulin injection from 40 units to 24 units. Dumped a lot of my drugs and remain extremely well some 4 years on even though my doctor expected some deterioration in my health i.e. developing some of the problems diabetic used to expect to get. There are many people, past and present on this site who have completely reversed their diabetes. I won’t name them but if they are still around and posting often.

  Having said all that, the 800 calories was designed for diabetics and I wouldn’t expect anyone to go on such a strict diet for more than a few weeks if they didnt have diabetes. On the other hand, this diet works well in losing weight in general but it should not be a long term plan (as it is for me) but a kick start to healthier eating. If you are not diabetic or pre-diabetic I think the 800 number can be a variable. The most important part of the diet for me is the low carb aspect. Again for diabetics, carbs turn to sugar in the blood stream so for years we were told to avoid ‘sugar’ type sugar but never to avoid carbs, until Dr M.

  Enough of that but if you are interested in the science behind the diet please search for Prof Taylor, Dr Unwin and Dr Mosley for their studies in reversing diabetes.

• posted by DoubleDutch
  on 16 Jun 2020 at 14:49

  

  Yesss thank you sunshine girl! I knew part of this story but not all!
  Good work on lowering your medication! Very impressive. I want to tell my father in law about this, but he’s not ready for really low carb.
  I’m not diabetic of even pre, but Im happy I did the 800 very strict for 8 weeks, because I also prefer loosing the fat around my organs! I started to do days with higher cals after 8 weeks during my skiing holiday. Now I make sure to average the 800, because I still like to discard around 4 kilo. I’m nearing my 6 months anniversary of fast 800 and I think it’s time for maintenance. Or perhaps 5:2. Scary step though.

• posted by sunshine-girl
  on 16 Jun 2020 at 15:17

  

  Hi DD, It is very difficult for diabetics to get their head around the science of low carb when we have had it rammed down our throats that carbs should be eaten as the main glucose balancing mechanism in a diabetic diet. So I was told to eat cereal for breakfast, have a rice cracker for mid morning snack, always have a carb with a meal so rice with lunch and potatoes with dinner. No, no, no. That was the biggest load of rubbish until Dr M came along and saved my life. One reason why diabetics are told to eat lots of carbs is to keep their blood sugar high to stop them going into a hypo or coma, which to me is like telling an alcoholic to drink plenty of whiskey to keep their blood alcohol levels high so they dont get the tremors. As you can tell, it makes me so mad that they have been getting it wrong for years and some still are. With regards to your father in law, might he be persuaded to reduce the portion size of a carbs on his plate so it becomes a small part of the meal rather than the main event, think of spag bol, how many people have a pile of the pasta and some meat and tomato sauce. The best diet in the world is the Med diet which allows a small portion of rice or pasta with a main meal. Must get off my soap box, just give him a little nudge (or buy him the BDS800 book – not the Fast 800). Hope that helps.

• posted by sunshine-girl
  on 16 Jun 2020 at 16:53

  

  Just one more thing DD, if your father in law falls within the people who are too old and doddery to control BG and manage medication then they should not be going on this diet because they are the people I mentioned before who might become hypo. If he is a sprightly bloke who knows how to look after himself then he could maybe try the diet but moderating it to just lowering carbs.

• posted by Kevlondon
  on 30 Jun 2020 at 20:33

  

  I suspect the thinking behind 800 calories is that it’s low enough to ensure some weight loss, given how many calories our bodies burn just to keep us alive. And it’s high enough to ensure you can eat 3 times a day, or at least fairly substantially twice a day, to ensure that the plan is sustainable.
  The idea being, if you can stick to 800 calories for 12 weeks, most people will have lost a good proportion of the total weight they are trying to lose, meaning they can move to a more slow and steady and sustainable form of weight loss, e.g. maintain low carbs & sugar, but push calories up to 1200 a day, or even more if their lifestyle warrants it, and thus continue to lose weight at a slower pace to get to their target.
  This is just some brief thinking and the application of some common sense – I haven’t studied this, and I’ve only been on the plan for a week, but it seems a logical interpretation to me.

• posted by sunshine-girl
  on 30 Jun 2020 at 22:16

  

  The main thing is the shock to the body to rid us of visceral fat, especially around the liver and the pancreas to kick start the insulin production. This works to some degree depending on how long you have been diabetic. For me, 14 years was too long but it has reversed the continuation of the bad effects of diabetes. So no neuropathy or eye or kidney damage, which would have been expected after 15 years with diabetes and on insulin. The insulin also being most of the problem, so try not to go there.

• posted by JGwen
  on 1 Jul 2020 at 15:49

  

  I was listening to a podcast the other day on the dietdoctor website. – The person being interviewed did waffle on at times, but he did make one interesting point. He is a doctor who was obese himself despite watching what he ate and following all the “accepted” guidelines. – He mentioned that the evidence is a very low calorie eating plan at the start is statistically linked to long term success at maintaining the weight loss.
  Obviously that bit of data is not enough to work out cause and effect. – It could be that the rapid weight loss at the start inspired people to keep up. It could equally be that those willing to stick with 800 calories or less per day are more motivated / determined to loose weight and that’s reflected in the long term outcomes.

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