TDEE for the Curious (or Why Don't I Lose Weight Faster?)

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TDEE for the Curious (or Why Don't I Lose Weight Faster?)

This topic contains 205 replies, has 61 voices, and was last updated by  MrsP2008 5 years, 11 months ago.

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  • Hi JoJo58, Ive, just read your post and feel much better. I’ve been doing 5:2 for 7 months and have lost only a few lbs. According to my TDEE I can eat 1700 cals! if I did I would be huge!! I’m going to try 4:3 and keep my calorie count to 1200.

    I hope the weight will come off soon.

    Thanks for your tips.

    Am I the only one who is slightly alarmed by the incredibly low number of calories for non-fasting days being bounced around here?
    I remember from the days when I read all about diets that you should never go below about 1500 cals a day – and that only for a short amount of time.
    Here I’m reading numbers below that and for the 5 days in between the 500-600 cal days.
    Take care people – don’t go radical. You will do yourself more harm than good and it could be outright dangerous for some.

    Hello Kirsten70 What makes you say that? There is a large and growing bank of clinical evidence that shows this diet has major health-giving benefits..

    Golly, I love danger!

    Only problem Im having is oodles and oodles of energy, I’m bouncing off the ceiling, swiped my son’s beat pill yesterday, surprised I dont have an ASBO, singing loud enough to take the roof off – and dancibg like no-one is watching – at least I hope no-one is! OH did point out I was cruxifying ‘Jerusalam’ when I continued today. Though he thought my Monkees entire hits was quite good.

    Dont think Ive hit 1500 calories more than three times in the past three months, I havent become beautiful in the meantime – such a pity – but my hair and skin is blummin’ good, and Im losing weight quite steadily, . Not bad for an old broad who is reaching 60 next year! Between 6-10 a day portions of veggies a day.

    Researching and seriously thinking of a longer fast than 36 hours, would love to know if anyone has done one! Not thinking of anything too drastic, a few days is radical enough for me.

    Im spot on four months today – Ill leave it go the maintenance crew to chip in how they are doing long term, because the longterm benefits are what is most important about this WOL!!!

    Hi Kirsten:

    Perhaps you might be interested in a very well written article on fasting – it may contain information you are not aware of:

    Hi Milena–

    I have fasted up to 10 days at one time. It was a personal choice and beyond 48 hours I experienced real energy–no hunger–and the best sleep of my life.

    It was water only– and I broke it with some yogurt–then very light eating for a couple days (1,000cals spread out over a couple meals)

    Right now I am doing 36 hours early in the week –then a 24 hour before the weekend. Omnly 10 lbs from my ideal weight, I do it to free myself from the snare of food– so I can realy think about what I am eating when I do actually sit down for a meal.

    Good luck!

    Hi Pastor Dave

    Im so tempted, been reading a lot about it. I work from home, so I think its doable. Think Ill extend my 36 hour on Monday to 48, and see how it goes. Im sleeping well too.

    Just 10lbs away? Brilliant – hss it been a long journey?


    My name’s Rick, I’m a GP and wanted to say this is such a good posting! Top point, well made, excellent communication.

    That’s all, really.


    I see to have very unintentionally ruffled a few feathers here. Please forgive me.

    I am not:
    – condemning or questioning fasting in any way (why would I be fasting if I was?)
    – condemning or looking down on anyone regularly eating only small amounts
    – trying to say I know better than anyone else

    I am:
    – expressing my own personal concern about the few people who would appear to be cutting back incredibly radically and to what could potentially, for some people and in some cases, be a dangerous level
    – expressing my own personal concern about at least 1 person who has posted in these forums who is still growing and consuming incredibly low levels
    – expressing my own personal concern for the 2-3 people who, when reading, sound like they could really do with confidence building and help in accepting themselves rather than following incredibly harsh, self-imposed regimes – and here I stress that I am talking about 2-3 people.

    I guess I am / was trying to reach out to those very few people to attempt to set an alarm bell ringing.

    Once again, I apologize very sincerely to any / all people who do not fall in that restricted category whose feathers I unintentionally ruffled.

    Who are the 2 or 3 people you are discussing? Your comment was 1500 calories was too low, some of us have a TDEE below that, or at least will at target weight.

    Although many of us stay within TDEE every day, not many going to 500 every day, though I often have 3 or 4 days a week well under 1000, in addition to fast days under 400, and quite often nothing. But some of us do. Is this radical? How do you know?

    Haven’t noticed a lack of self confidence. Though I am beginning to think a lot of what we have been taught about eating is tosh. Breakfast is the most important meal of the day, don’t skip meals, butter is bad for you, eat low fat. I could go on. But if it is dangerous to go below 1500 cals – except for a short amount of time, why have people fasted for centuries, and fasting for hours, days or even longer, might actually be good for you. Now thats radical thinking.

    Careful Milena! You could get locked up for such reckless thinking! The woman has clearly gone mad! Ergo fasting must be bad for you… 🙂

    A heartfelt post aimed at reaching out to a couple of people whose posts came across as potentially alarming has turned into a sniper’s field.

    I feel saddened that no one else would appear to care about the couple of people it was aimed at or even to consider that what these couple of people are doing could be potentially harmful.

    I also feel saddened that several people have reacted as if I am criticizing them. If you do not feel that you are one of the couple of people I was reaching out to, you can just ignore it or post helpful comments. Nastiness gets no one anywhere but in the dumps.

    Should you feel the need to reply to this, feel free. However, I will not be following this particular thread any more. It’s a shame though, there were some very good posts and supportive, helpful comments coming out along the way. Thank you very much to those who have been posting such wonderful material and thoughts. I appreciate it.

    One last comment before leaving this topic completely.

    I re-read my original post and see how it could possibly have been misinterpreted by some people. It was not restrictive enough in its wording. I apologize yet again if some of you think I was criticizing you, although I do not understand how. There is nothing critical in there.

    I will, however, not apologize in any way for expressing my concern for others.

    Hi Kirsten

    I certainly wasn’t sniping at you, thought it was an interesting topic, your comment was that you had read somewhere eating below 1500 calories – except for a short time – could be dangerous – I simply put forward the counter argument that 1500 calories was more than the recommended maximum for a lot of people, and that I was experiencing great benefits when eating regularly below this.

    You made this comment on a forum with a basis in fasting.

    You did not direct the comments at anyone in particular, though in your second comment you referred to some people without naming or talking to them directly. It was not at all clear that your first comment was aimed at anyone in particular.

    You commented about ruffling feathers -twice- and then expressed an opinion that some people – still unknown – needed confidence building and needed to accept themselves as they are.

    If this was not a criticism, it was certainly a little patronizing.

    Nevertheless, I didn’t snipe. I certainly didn’t take anything personally – even though I do fall into ‘that restricted category’.

    Sorry to see though that you feel sniped at – or had your feathers ruffled, as you would put it. It was not my intention to upset or offend, but I asked for longtermers to chip in, and one did. With humour too!

    Pity to leave now when there is an opportunity to discuss what benefits fasting holds for us all. Such a huge topic, and until recently I might have thought your 1500 calories comment was, if anything, on the low side. And that missing lunch was radical, especially as being a second breakfast hobbit is what brought me here in the first place.

    So the least you can do is stay on thread,stand your ground and make your argument, but do it by chatting and speaking directly to people, rather than throwing out comments meant for individuals.
    I look forward to chatting with you again soon.

    Hi Kirsten, although you haven’t directly named me, I would imagine I might be one of the 2 or 3 people whom you are expressing concern about, as I have stated that I consume on average around 1100/1200 cals on non fast days (generally).
    Like I said above this is totally normal for me, not since starting 5:2 but pretty much all my adult life… I’m 36 years old.
    As I also stated earlier, my TDEE is 1485 and BMR is 1237, these numbers are based on my current weight. So in fact my normal eating habits don’t come in much below.
    The questions I asked in my post were not based on lack of self confidence, and I can assure you I am more that happy with myself. But the fact of the matter is that I am aprox 8lb overweight, and wish this not to be the case. For health reasons, not vanity.
    I only wished to ask for a little advise from people who are more experienced in all things 5:2. (Which I got, and am very grateful).
    I have spoken to my GP and an endocrinologist about the 5:2, this lifestyle change, and my consumption, and they both assure me it is safe and healthy to continue.

    If you weren’t referring to me, then just ignore this post.
    If you were, thanks for the concern, but I’m fine.

    This has been the most effective and easiest diet I’ve ever done. I lost 2 pounds a week (2 stone, and 6 inches of girth, in total) like clockwork until reaching my target, which put me just inside my healthy weight range. On non-fasting days, I ate as much as I felt like and was surprised to find this ranged from only 1600 calories (which is about my BMR)to about 2400 calories a day. (Both this site and the Mayo Clinic give my TDEE as about 2250.) Among other things, I have noticed that my appetite is much less since starting the diet, and sometimes it even feels like a struggle to eat 600 calories on a fasting day (I now do it all in one go at dinner time.) My activity levels also fluctuate quite a bit — tennis and HIIT three times a week, but often quite sedentary on other days. This no doubt accounts for the variations in my appetite, though I haven’t noticed a direct correlation between high activity days and high appetite days — in fact, I have preferred to do my exercise on fasting days as that is when I have felt most energetic (!) and I want to enjoy the benefits of exercising in a fasted state.

    After several weeks of maintaining, I am now aiming to lose another 5 pounds, partly to provide more of a cushion, and partly because my cholesterol is still higher than I’d like and I want to see if losing a bit more visceral fat will have an effect. The thing is, I’m starting for the first time to feel drained on fasting days. This raises two questions: (1) could simply this mean that I am having more difficulty drawing energy from fat now that I’ve lost so much of it, and (2) more generally, shouldn’t TDEE and my target calorie intake vary according to how active I am from day to day? In other words, if my average TDEE is 2250, doesn’t this mean that on inactive days my TDEE is actually closer to my BMR, while on very active days it must necessarily exceed 2250?

    Hi Ian
    You’ve done really well so far. If you want to still lose weight, why would you need to eat more on some days? Your TDEE is the MAXIMUM, not the compulsory eating limit. On fast days, keep well below 1/4. No need to “eat up” to 600 cals. 🙂
    Feeling more energetic and wanting to exercise on fast days has always been our experience too. I’m not sure where in the world you are, but if the weather is hot (ie summer), perhaps this might explain your tiredness? I am more energetic in colder weather. Also, look at the foods you are eating. Are they encompassing a wide range of foods, meeting all your body’s needs? Eating too many starchy carbs can slow you down. Have a look at the patterns of you carb consumption.
    Just a few ideas. Cheers PVE

    Hi Ian:

    Congratulations on your weight loss – it really does work!

    To address your questions – you are not having more difficulty in drawing energy from fat. The average, normal/healthy weight person has several months of fat reserves available, and the body has no trouble using them if needed. If anything, after your weight loss your body is better at using fat than at the start of your diet.

    As for your TDEE changing by day – I would not worry about it. Even with the large number of calorie counters around that seem to give a precise number of calories burned (seem because all testing shows they are wildly inaccurate – 10 to 20% or more off), any TDEE number you might come up with based on calories burned that day is only an estimate. While you may burn more calories one day than the next, you really cannot know what the difference is. The average daily TDEE estimated by the calculators is all you really need – especially as you have lost weight quite nicely using the estimate given.

    I would guess your ‘feeling drained’ is a temporary thing. Your body has undergone quite a few material changes in a short period of time and it does take awhile to adjust to the ‘new you’. I would just keep doing what you have been doing to lose the last five pounds. If you feel that inappropriate, perhaps do only one diet day a week for awhile, understanding your rate of weight loss will slow.

    Again, congratulations!

    Thanks, PVE and Simon.

    First, I’m not looking to eat more calories, I’m trying to understand (and refine) the pattern. On non-fasting days, my natural calorie intake has been between 1600 and 2400. I generally have been eating what I want and do not overly restrict myself other than keeping to 2400 as a maximum, and my diet has been well balanced. Only now have I checked my TDEE and learned that it is 2250, not 2400 (acknowledging that this measure as well as my calorie consumption are at best only rough estimates).

    So one question is whether I ought instead to have been using 2250 as my maximum rather than 2400, or whether the fact that half the time I naturally eat way under the maximum means I should not worry about exceeding 2250 on some days. (I have been averaging about 1950 calories a day on non-fasting days, and 1450 overall, including fast days.) It seems logical that if the TDEE is an estimate of my average calorie needs that I’ll need less than that on some days and more on others. That said, I’m not complaining about my results so far, nor am I particularly worried about the relatively small difference between 2250 and 2400 — I am just curious how we should be treating TDEE.

    The other question is whether, now that I am no longer feeling the huge boost in energy I experienced when I started the diet and do in fact feel I’m running out of energy on high-activity fasting days means I ought to change the pattern and do my exercise on non-fasting days. It is easy enough for me to experiment and see how that works, but I’m interested to know what others say based on their own experiences and the theory.

    Hi Ian
    Two things:
    My understanding is that exercise is more effective on fast days. I know they are the days when I run everywhere and feel 12. 🙂 I’ve been doing 5:2 for 2 1/2 years now and it is unusual for me to run out of energy on fast days even though I eat only 350 cals in the evening and have very little fat on my body now.

    If you set your TDEE at the level it will be when you reach your goal weight, and set the activity level to sedentary, you gain maximum benefit from fasting and learn to eat as you will for the rest of your life. So, no, I would not be eating those extra cals if you can manage learning to eat less.
    All the best. PVE

    But what do you mean by “those extra cals”? If the TDEE is the average we’re meant to eat on non-fasting days, then some days will be more and some less. If I’m eating under the average, what is “extra”?.

    I don’t want to push my targets so far that dieting becomes a chore, as one of the many benefits has been that I don’t have to interfere with my social life beyond a few minor timing adjustments. I am already eating noticeably less on my non-fasting days than before I started (because my appetite has adjusted, not through conscious deprivation).

    I am encouraged that you don’t run out of energy on fasting days, but I do now, so I wonder if rearranging my pattern (without increasing the average calories) might correct that. (Also, I can still exercise in a fasted state without doing it on a fasting day — I would just eat normally afterwards, so I wouldn’t run out of fuel.)

    To expand a bit, my current pattern is to begin my fast at 11pm or midnight, do tennis and gym around midday the next day, followed by a small portion of complex carbs to replace my glycogen stores, then have a normal dinner. The next day, I do tennis and gym again after midday then break my fast and resume normal eating. This worked fine for a while, but I find I’m running low on energy before dinner on the first full fasting day, though I don’t feel hungry. I think it might be wiser to eat my one meal in the middle of the full fasting day rather than wait till dinner, though this would prevent me from having dinner en famille on a fasting day.

    While I enjoy the midnight to midday two days later pattern, which is the least disruptive to my social and family life, I think I may have been overdoing the exercise a bit. I thought perhaps the reason I was running out of steam might be that the generous store of fat around my middle is all gone, I still have 17% body fat, so it seems more likely it is stretching my fasting period a bit too long.

    Hi Ian:

    I’ll begin where I ended my initial post – if you are getting the results you want, ignore TDEE.

    You have obviously been on a very low calorie diet. To lose 2 pounds a week for 14 weeks you must eat 7000 cal. per week less than your TDEE. That means that in addition to your two diet days, you are also cutting about 6-700 cal. per day out of each of your 5 non diet day calorie counts.

    You are now complaining of a lack of energy. My simple suggestion was to eat more (do only one diet day a week). This will slow your rate of weight loss, but as losing weight does not seem to be a problem for you, eating a bit more, along with time for your body to adapt to your lower calorie intake, will probably take care of your lack of energy. Remember, when you hit your goal weight, you will be able to eat even more than you have been. This will probably be the biggest challenge you will face – ‘keeping it off’.

    Again, congratulations on your weight loss (and fitness efforts)!

    Thanks again for your thoughtful and helpful reply. I want to stress, though, that I only lack energy during part of a fast day (when I go 19 or 20 hours with minimal intake). I never used to lack energy while fasting (quite the opposite), so if insufficient body fat is unlikely to explain the lack of energy, it must be the eating pattern. Rather than add more calories on a fasting day, it makes more sense to rearrange them and have a small lunch and dinner, rather than one big dinner.

    I expect I will switch to 6:1 in a week or two when I reach my weight goal, but I still want to avoid any lack of energy on my one fasting day.

    Human bodies are complex organisms, Ian. You have clearly understood your body’s needs to this point. It is all trial and error. If what you are doing doesn’t suit, try something else. Life is an ongoing experiment. 🙂
    All the best. PVE

    So, I’ve lost my extra 5 pounds (a little over 7, actually), but just over half of the loss was muscle mass. I know this from the readings from a state-of-the-art machine at the office of a friend who is a state registered dietitian. Now that I have reached my target weight and body fat (16%), I do not wish to lose more muscle mass by continuing to eat way under my TDEE.

    Incidentally, the machine gives me a TDEE of about 2550, as opposed to the 2250 estimate given by the online calculators. I’m not going to worry about the relatively small difference between 2250 and 2550 and am happy to aim for the average of 2400. What I believe I should avoid, though, is eating only 1300 or 1400 calories except on my fasting day (and I’m now doing 6:1 for maintenance).

    I am aware that my decreased appetite makes it easy to undereat, but I think it’s important not to let my calorie intake drop so low that I lose more muscle mass. Listening to my body instead of my brain may not have been best after all.

    Just to follow up 6 weeks on, as I’ve reached my target weight and am not looking to lose more, I’ve been eating much closer to my TDEE and not (except very occasionally) doing any 600-calorie fasting days. Instead, I’ve been doing something like a 16:8 two or three times a week, skipping breakfast and exercising fasted (tennis and no more than 20 minutes in the gym). I do tend to eat fewer calories on the exercise days, but generally about 1,600-1,800. I have not been experiencing any sudden tiredness, nor the sort of 5-pound weight swings I had been experiencing. I have stayed 2-3 pounds under my target weight (which was already 5 pounds lower than my original target), and now the machine reading confirms that although my weight is slightly down from 6 weeks ago, there is no loss of muscle mass. Body fat is down to 15.7% (from 16%).

    Every now and then I have done the odd 600-calorie day (one meal in the middle) when I’ve noticed my weight creeping up a bit, and I am gratified that that sort of fasting is still as easy as ever, but I think that aiming for a couple of 1,600-1,800 calorie 16:8 days a week is a good and palatable maintenance regime that will still give me the benefit of IF.

    thank you for this post. I am new to 5:2, in my second week and just finished 3rd fast yesterday. I went to the Mayo clinic link and learned that my TDEE is 1800 calories a day, which translates into 450 calories on fast days. This means I consumed 900 calories less the first week, which does not even add up to a pound. This may be why I have still experienced no weight loss, but I did lose 3 inches of stomach fat and my pants fit better. thank you, J23

    Hi juno and welcome:

    You are welcome.

    Many know the definition of TDEE, and have even computed it on a calculator. But not many really understand the ‘numbers’ they have to confront to lose a lot of weight. I believe understanding the numbers can lead to less ‘quitting’ and more successful weight loss.

    What does BMR stand for?

    Hi qcfox:

    BMR stands for basal metabolic rate. That is the number of calories a body uses at complete rest – think coma. It is an unimportant number when discussing weight loss. The important number is TDEE. There is a TDEE calculator at the top of the page under ‘How It Works’.

    Good Luck!

    I always eat too many calories after my fast days but I eat natural foods rather than processed foods whenever possible and try to have sufficient fibre, fresh vegetables, iron and good oils etc. I count calories on my fast days and otherwise concentrate on nutrition. I find counting calories all the time too difficult to continue in the long term and find it an added complication. So far I am still losing weight but when that stops I will start looking at my TDEE if I want to go lower. I have been on the 5:2 diet for 6 months now and lost two stone.


    I completely agree with you and that’s how I approach it too. Interestingly, Dr. Krista Varady, began her research on that premise: people (and mice) who have no idea how many calories they’re choosing on food days would increase their intake but not enough to equal the decrease in their intake on fast days. What she found was that there was an increase but it was even less than she anticipated.

    Dr. Varady’s book based on that research is “The Every Other Day Diet” and Dr. Mosley based his eventual program, in part, on her research.

    I just find it simpler and more satisfying not to deal with the math of it all so long as I eat quality veggies, proteins, fats and beans and avoid what doesn’t help me stick to my program. Seems to work! And I feel as good about the process as I do about the results. I have been freed from life-long impulses to eat poor quality nutrition and massively overeat in the bargain.

    So..from what you are saying it really isn’t possible that this is the holy grail of dieting where I can fast two days and eat what I like … I.e a bit of cake if I want, eat out in a restaurant etc and not count calories which is what the book says …. so this diet is like any other diet which is based on restriction!?

    TishTash, we’re all overweight through eating too much of the wrong stuff too often! So no magic possible😥. But you can do any of those occasionally, which you can’t do successfully with other diets, as they are all wagons to fall off. Of course cake, restaurants, wine etc repeatedly would just negate the fast days. But if you eat healthily avoiding all added sugars and using lots of multicoloured veg, plus fish, meat, eggs, nuts, olive oil and natural fats in dairy etc. most of the time, fast two days in 5, you will lose weight even with the odd piece of cake or restaurant meal or glass of wine. You will probably also get stalls and plateaus in your weight loss. That’s the time to do the other things: counting cals on non FD days just to self check, reducing carby foods further, exercising more, using 4:3 and other good suggestions on here. My weight loss stalled quickly about three weeks in, probably because I’ve dieted before ( always more difficult as your metabolism has usually gone permanently lower), but by keeping going it started again and I’m now down 20 lbs in spite of several parties, weekends away, comfort eating days and odd treats here and there. Though if I’d not done those things I’d probably be at goal weight by now! No, you don’t need to count cals on non FD days, unless you’ve stalled, but eating healthily is a necessary part of it. This is sustainable precisely because of its flexibility, but that doesn’t mean you can just eat as much as you like of everything.. This weight took years creeping on and we are now having to make up for that, so there’s going to be some restriction.

    Tish Tash,

    You have to be realistic. There is no such thing as a magical bullet that will cure all your ills while allowing you to do as you please. I don’t think this diet is like other diets. It does allow you to eat what you want on the 5 days if that’s what you want to do. But then don’t expect to achieve the same results as someone that chooses to eat in a more healthy reserved manner. It just cant work like that?? I don’t count calories at all. My one fast day is water only. My six non fast days I don’t count calories but I choose not to eat foods that aren’t good for me. I avoid sugar like the plague. Chocolate no longer holds an interest for me. I do not eat bread, rice potatoes or any carb dense foods.

    That’s not to say I don’t have these foods sometimes but there has to be a good reason. A special birthday etc. The book says to eat up to your TDEE on NFD and 500/600 on FD. You don’t have to count calories if you have a sense of how much food 2000 odd calories looks like. Trouble is most people have no idea what 2000 calories looks like. You’d be stunned at how little it really is. So best to count calories to start with until you get a feel for how much 2000 looks like. The one thing I can say is that the longer you do this diet for the more you will tend to gravitate to a healthier eating style. Well for me at least it came naturally, it wasn’t like I was forcing the issue.

    Give it a genuine try. It works. If your expecting magic then no it wont work for you. Success doesn’t chase you, you have to chase it.

    Like BigBooty, I rarely count calories on nonFDs, but when I do, just to check what I’ve had, it’s never more than 15/1600 max. The advantage of keeping sugar and carbs down is that you usually stop quicker!

    I think some of the point is being lost here. Weightloss is only PART of the benefit of 5:2 (arguably the less significant part). There’s increasing medical evidence that Fasting for 16+ hours has alsorts of cario-metabolic benefits well beyound weight loss. Risk of heart disease; diabetes; cancer; dementia – which are the major killers in western society- all seem to be reduced by fasting. Add to that eating mindfully and healthily; getting sufficent sleep of good quality; moving around a lot and doing some strenght and some high-intensity exercise are additive. In combination these lifestyle choices give us the best chance of living into old age and being happy and healthy while we do. Try googling Blue Zones TED talk for more.

    Bottom line: This is about lifestyle choices and let’s not over-concentrate on weight-loss.

    Hi Tish and welcome:

    Sorry, but all diets are based on calorie restriction. You can eat as much of anything you want at any time on this or any other diet, but just don’t expect to lose weight, too. I feel the book did a disservice to many because it said people could eat ‘normally’ on 5:2, but then did not define what ‘normally’ meant. For overweight people, eating ‘normally’ means over eating and if people come to 5:2 and over eat five days a week they at best lose a small amount of weight or just stall their weight gain. Many have quit the diet as a result, and continued their over eating habit. It is usually easier to go back to eating ‘normally’ than to eat in a way that will cause weight loss.

    Your choice.

    Good Luck!

    Hi graham:

    Most people that come to 5:2 do so to lose weight. It is proven safe and effective for that purpose.

    There are no studies that show 5:2 provides any other health benefits, like longer life, less cancer or better health in general. Nor can there be. Studies to prove those claims would take decades and be almost impossible to monitor over that time period. People on 5:2 can eat anything they want, drink anything they want, exercise as much or as little as they want, smoke or not smoke as they want, and do anything else they want or not. So trying to say people that follow 5:2 will be healthier over time is easy to do but impossible to prove. But then, there is the placebo effect!

    Now ‘fasting’ is a different subject. But all studies to date show that to get material benefits from fasting you must periodically fast (water fast) at least four consecutive days. But that has nothing to do with 5:2 (or 16:8 or whatever). However, 5:2 can act as an introduction to fasting and lead to other proven, more healthy, ways of living.

    Hi Simcoeluv- I don’t agree! Take a look at the original programme which is is as fresh and relevant today as ever it was.. and there has been much scientific work done since

    Since I started on this, I’ve been reading huge numbers of scientific papers, and it’s clear that while weight loss itself can be as simple as restricting calories, it goes on from there to be much more complex, especially when you include other health aspects. Caloric restriction using IF and a small amount of food (translating to 500cals) extended the lives of mice and did other things too That’s what prompted Krista Varady (originally one of the researchers on longevity) to explore IF using 500 cals with humans, primarily for weight loss. The groups of humans that calorie restrict as a permanent way of life have very good blood tests and blood pressure, but they don’t smoke and drink either. They are not part of a scientific study, though I suspect they are attempting to keep some records, there being scientists among them.

    Simco is right in that there are too many variables in human eating and living habits. And nutrition is incredibly hard to study even in a project because of all the many variables. Some of this seems to be responsible for the controversy we’re in over fat (eg earlier researchers didn’t account for the fact that people being studied were eating high carb as well as high fat and they didn’t separate these two items adequately, nor the smoking). The whole issue of calories is complex; for example, take fats: Phinney showed that certain types of fat (short chain, saturated) are used immediately, not stored, while Polyunsaturates are stored if they aren’t needed immediately. If you are eating lots of carbs they will be stored in different places, some where they can be used fast, others for slower use and these last might not be needed if you go on eating lots frequently, so they mount up. But with eating gaps through fasting your body needs to draw on fat stores and can only do so effectively if your insulin has been allowed to subside (eg through no sweet or carby snacks!). So some of that info needs to be added to the notion of what to eat when you aren’t fasting.
    Calories are not equal in their physical effects: 100 cals of fats (about 11 grams) won’t spike your blood sugar on its own; 100 cals of sugar (about 25 grams) will, and insulin will be released to get it out of the blood into storage. It gets more complex when you look at mixing these things, but part of the problem is that sugar we often eat on its own or else with another carbohydrate, a double whammy as the body treats them as much the same. While insulin is high, fat won’t be taken from fat cells for use in the body, so you’ll start feeling hungry again instead, maybe with carb cravings too. So have your burger, but give the bun to the birds!

    Oh no Apricot!

    Please don’t give the bun to the birds! That carbohydrate isn’t good for us, it’s not good for the birds either! In excess it causes a whole host of health problems in birds, reduces their fitness and can result in disability and death.

    “Have the burger, but throw the bun in the bin” 🙂

    What about composting the bun? Will this result in obese worms? 😊 P

    Round where I am they are sea gulls, who seem to be well adapted to pretty much everything, including children’s ice creams with child attached!

    Being apparently well-adapted to something and that something being good for are aren’t necessarily the same thing of course… Hence the obesity epidemic in humans….

    Absolutely, Happy!


    Means for best health seagulls should leave the ice cream?

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