The Basics for Newbies – Your Questions Answered!

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The Basics for Newbies – Your Questions Answered!

This topic contains 537 replies, has 177 voices, and was last updated by  Kay-50kg.goal 3 years, 2 months ago.

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  • Hello Newbies and welcome!

    Somehow, you have run across 5:2 and this site. Many of you come with questions, doubts and skepticism. Most of your questions have been asked and answered many times by many people, but they are new to you. You may ask a question on this site and not get an answer, depending on the thread you choose to use or create.

    So this thread is for you. Ask and wonder, and we will try to get an answer for you.

    To start out, the way 5:2 works is you go to bed, get up, eat 5/600 or fewer calories during your waking hours, go to bed, get up and eat to your TDEE or less – twice a week. On all 7 days of the week you can eat foods you want to eat – there are no forbidden foods, or foods you have to eat. For the first month or so focus on doing your diet days correctly (5/600 calories or less) and most everything else will fall into place.

    That is 5:2, pure and simple. Anything more is not 5:2, and is not necessary to get started and succeed.

    There are several posts that answer your most common questions. You can read them now, or when the question comes up. But in the following posts, well over 95% of the common questions are addressed. Here goes:

    (1) The basics: Two additional warnings that I would add to the post if I could are these: (a) You might get cold. About 10% of your body energy is used to digest food. Digesting food creates heat. If you don’t eat because it is one of your diet days, you are not digesting food and heat is not created. Some, but not all, people on their diet days report they feel cold. I put on socks and add a blanket at night. (b) You might get a headache. Your body gets up to 40% of its daily water needs from the food it eats. If you don’t eat, you are shorting your body of water. Most headaches can be prevented by drinking additional water on your diet days. If that does not work, a shortage of salt is a secondary cause. Drinking some bouillon, which is mostly salt, or putting some salt on the food you are eating will usually do the trick.

    (2) You are not losing weight consistently: This is for people that either start out OK and then stall, or don’t lose weight right away at the start.

    (3) You have not lost any weight for a month or more (if your timeframe is less, see 2, above): This will show you what you need to do to resume your weight loss.

    (4) You are not losing weight fast enough – this will explain why, and how much weight you can reasonable expect to lose over time: Unreasonable expectations of how much you will lose on 5:2 (or 4:3 or ADF) can cause you to quit for no good reason.

    (5) You have started your diet and started exercising, too, and your results are not very good: It turns out that while exercise is the single best thing you can do to improve your health (unless you are a smoker – quit), it does not really help you lose weight faster. If you think it will, and you are not losing, you might quit when you should really keep on the diet.

    (6) You are confused about how much time should pass between meals: Bottom line, this is a weight loss diet and time between meals is irrelevant.

    (7) You go off 5:2 because of a great weekend or holiday and come back having gained quite a bit of weight: Just keep doing 5:2 and don’t worry about it.

    The above address most of what comes up. Many people have many personal answers that work for them but not necessarily for everyone else. I believe you should start with the basics, and worry about other things only after you have done the basics correctly and they don’t seem to be working for you.

    Good Luck!

    Please can you tell me if it’s okay to have fruit tea on fast days?
    I believe they are nil calories, many thanks

    Read simcoeluv’s third paragraph, the answer is right in there:

    “On all 7 days of the week you can eat foods you want to eat – there are no forbidden foods, or foods you have to eat.”

    You can drink full fat coke and eat ice cream on your fast days – as long as you stick to the calorie limit. If you want to drink something calorie free it’s even better because you have more calories left for food.

    On why eating fat is good for you, not bad:

    Dr. Longo on fasting and cancer treatment, cancer prevention and 5:2:

    Drs. Stephen Phinney & Jeff Volek outlining the research on low carb diets:

    A wonderful post on 26th – thanks simcoeluv… On week 7 and regularly read forums for continued inspiration and a reminder of why I am living this WOE – and it’s doing ‘what it says on the tin’ 😉

    started yesterday with a fast day, not too bad not weighing till I’ve on this for a week or two going to measure my gut however and start working out again. Moved from Florida back to my home state of Oklahoma don’t laugh it’s a long story. I’m happy here because I found a great guy, but the way people cook out here is not healthy (chicken fried everything)! Wish me luck! I really like having a forum to share with others who are going through the same things as I am.

    PS I’m a LOACA

    mitziday, what is a LOACA? I keep seeing this in the Forums but I don’t know what it is.

    On fast days can I do a full fast and not eat at all, would this do any harm?

    Hi judy
    LOACA is “Ladies of a certain age”, one of the most popular threads

    Hi Who and welcome:

    On 5:2 you eat 500/600 calories – or less – on your diet days. Many people do not eat anything on their diet days. Some call it a ‘water fast’ because they only drink no-calorie liquids. The TDEE post shows how many fewer calories you can eat doing a water fast on your diet days and how that might impact your weight loss.

    Good Luck!

    A clinical study on a variation of 5:2 that concludes it is safe and effective:

    Hi guys. What are the best apps to download for android.

    Hi girley:

    Last I heard, an android app was not available: – see 12 Jul 14 post

    Hello, Maybe I am missing this in the FAQ’s or some of the other posts. What about diet softdrinks like Coke Zero with no calories or Pepsi Max for example? Can you have these on fast days?

    Thanks, it’s also my first day!

    Hi Bellie:

    While there is much discussion about diet drinks in general, from a 5:2 standpoint they have no calories, but even if they did you could drink them if you wanted to.

    Good Luck!

    Thank you!

    Thankyou Simcoeluv 🙂

    Wow great.

    If the 5:2 premiss is extended fasting is the way to go, for overall health and not just weight loss, how can spreading the 500 / 600 calories throughout the day be ok? Even herbal teas have about 5 calories a cup.
    So by spreading the calories throughout the day instead of consuming in one go, one isn’t truly fasting surely?

    Judycin asked me what LOACA is it is lady.of a certain age menopausal or post. I’m 53 and have gained 20 pounds in the last.3 years that doesn’t sound like much but when you’re 5′ 2″ it’s 2 dress sizes. On my second week of 5/2 haven’t seen a loss yet, but I believe it will happen. This is something I can do for the rest of my life. Next week Vegas for a friends wedding. So no fasting then but I’ll get right back on it when I get home. Tried Beyond Diet for a week I’m sure it works it’s low cal low card and low fat, but who are they kidding no bread no pasta no wine, life’s too short, I’d rather be fat, so I hope this works for me I have a closet full of 2s 4s and 6s it makes me sick when I look at them.

    Hi Vet:

    5:2 has nothing to do with extended fasting. It has to do with calorie restriction. See #6.

    Good Luck!

    I thought the whole Michael Mosley documentary was about IT? That was sort of the point?
    I’m not talking extensive fasting. Just the 24 hour fasting. Grazing through the day on few calories is surely, in no way, fasting?
    Genuinely confused

    IF not IT lol

    Hi Vet:

    You are bringing your definition of fast to the table, but there are many definitions. Another is the willing reduction of calories (in this case) over a period of time. You are speaking of what is known as an ‘absolute fast’. 5:2 is not an absolute fast. The research from which 5:2 came was on severe caloric restriction. That is defined for 5:2 purposes as 25% or less of a person’s TDEE over a one day period. The short hand is 500/600 calories, which are based on ‘average’ TDEEs for women and men (2000 and 2400). A ‘day’ runs from midnight to midnight.

    If you read the post I referred you to, you know that 5:2 was not designed as a weight loss diet. The author and editors have caused much confusion by calling it a fast diet, not only because it is not an absolute fast, but also because it is not a quick weight loss diet.

    Some people like to overlay the absolute fast concept on 5:2, in any way they feel is correct for them. However, all of the research to date is on caloric restriction. Of course, if you don’t eat anything at all, you are severely restricting calories. But as the post points out, if you do a ’24 hour’ fast, say from 2 pm to 2 pm, and eat your TDEE before 2 one day and after 2 the next, you have done no caloric restriction and you will not lose any weight – despite having ‘fasted’ for 24 hours.

    If you are interested in 5:2, it is as explained as above. It is not confusing at all, and it works quite nicely. If you want to go into the jungle of 16:8, 21:3, 24 hour, only eat after 5 or whatever, it is up to you, but unnecessary to lose weight, and in fact may be detrimental.

    Good Luck!

    Thank you for such a fabulous response!
    My interest in the 5:2 is about the benefits surrounding both dementia and cancer prevention as opposed to weight loss.
    I agree the term ‘diet’ now lends itself to weightloss as opposed to a way of eating.
    The maintenance model also has my mind blown! I take it this is for people purely on a pounds to lose journey rather than other benefits.
    Good luck also!


    Your interest is shared by many, and 5:2 was originally created in search of a viable way to bring those benefits to the masses. Four and five day absolute fasts and constant caloric restriction are not feasible for a vast majority of people.

    It turned out that people who tried 5:2 for the ‘health benefits’ also lost weight. The market for a weight loss diet is much bigger than for a life extension diet. And that is where the ‘Fast Diet’ began.

    The research is very promising, but it is unclear whether 5:2 will be a player in that area. Fasting seems to have some extremely beneficial results, but the weight loss side effect is not helpful to someone already slim!

    Simcoeluv, your dedication to this site and it’s participants is outstanding.

    I would concur with your last comment. I expect the way to negate the weightloss effect would be to consume above needed calorie requirement on the non fast days?

    I myself, am hoping to fast alternate days. Dr Krista Varady made some very interesting points regarding the benefits of two day fasting as opposed to the alternate approach she herself researched. Did you manage to read any of her research?

    IF is amazing in its potential benefits. Any negatives are completely out weighed in my very humble opinion.

    Enjoy your evening.

    Hi Vet:

    I have read her research. Research on IF in general is at an exciting time. I believe Mattson is involved in a two consecutive day study now, and Harvie’s study on two consecutive days is posted above. I’m going to be interested to see if the ketogenic effect caused by not eating and/or not eating carbs over a period of time is an important factor in any benefits that may accrue from IF.

    One interesting thing to me is that 5:2 seems to work regardless of the food eaten. By that I mean if a person adheres to the 500/600 and TDEE or below pattern, they seem to lose weight and get improved blood work results regardless of the food in their diet. This was observed by Varady in her studies to date. Another interesting aspect is that most people that adhere to the guidelines over time report they start to eat in a more healthy manner. Of course, everyone has their own definition of healthy eating, but it generally seems to mean eating less junk food (sugar/processed carbs) and just eating fewer calories. The battle now is what food do you use to replace the calories no longer supplied by sugar and refined carbs?

    Whether a person chooses two consecutive or non consecutive diet days really depends on their schedules. Life gets in the way of plans sometimes. But both seem to work equally well. People that go for ADF, 4:3 or longer fasts usually are in a hurry to lose weight faster than 5:2 will allow. My observation is that when you are just starting, it is best to go with 5:2 and migrate into the other ones once you have been successful on 5:2 for a couple of months. By then your body has adjusted and you have confirmed it works and you can tolerate the diet days without too much discomfort. As with any diet, many people judge its effects quickly and abandon it if it does not immediately meet their expectations, whatever they might be. 5:2 is pretty slow acting and requires some radical changes in normal eating patterns that many find difficult. The drop out rate seems to be about the same as any other diet.

    I wish you success, and only counsel that you give it time to work. Those that have are quite happy!

    I’m new to the 5:2 after delaying starting it because I couldn’t find any validated evidence for it. So it’s a mark of how desperate I am that I’ll try it.

    On the face of it, it seems that 5:2 is just calorie restriction made more palatable by restricting the real suffering to just 2 days a week. What that means is that unless there is an increase in metabolic rate due to the eating pattern, the weight will return immediately one stops the 5:2.

    In my own case I have to reduce my calorie intake under 1000 calories a day to lose any weight. On 1500 a day I put on weight very quickly, despite being very active in martial arts (5 sessions a week) and tennis. I dread to think what would happen if I ate my TDEE of 1725. I have physical fatigue and a low mood most of the time.

    I’m hypothesising that my weight problem is due to leptin resistance and/or a (known) testosterone deficiency and hoping that 5:2 might help correct that so eventually I can eat normally without piling on fat.

    Does anyone have evidence of 5:2 resetting metabolic rate?

    Hi suthers:

    I am not aware that much of anything except starvation can reset a metabolic rate. Starvation will cut the rate by 30 to 40% once the body hits about 5% body fat, but that is about it. Research shows it can go down a little with fasting because energy is not necessary for digestion, but that it is not increased with, say, exercise. Basically, the research I am aware of shows that IF has little impact one way or the other on BMR.

    As you know, the metabolic rate is determined with the body totally at rest. It has little to do with weight loss. The key rate is TDEE, which includes the BMR but adds on the impact of movement.

    I don’t know why your TDEE is so low, and I’m not sure how fasting would impact it.

    Good Luck!

    suthers again:

    I missed your first comment. See my 15 Sep post above for a clinical study on 5:2 with two consecutive fasting days and a Med diet. It finds it safe and effective.

    Thanks simcoeluv.

    Hi today ..simcoeluv you’re a great wealth of information …thank you !
    I suppose the weightloss is different on everyone ? What would be the average loss for say ..a month .

    Suthers, have you had your body composition evaluated by Dexa scan, hydrostatic weighing or such?

    Your TDEE reads very low, unless you’re very slight and very elderly which I don’t think you are?

    I learned that I’m clinically sarcopenic from a Dexa scan (abnormally low skeletal muscle mass). My BMR was last formally calculated when I had my Dexa scan and estimated using my measured amount of skeletal muscle mass (rather than an estimate) and the Miffin St Jeor formula. At that time it was <1100kcals for the BMR with a proposed TDEE multiplier of 1.5 for days on which I kayak/strength train, and 1.2 otherwise. (I weighed 117lbs at that time.)

    I recently re-ran the calculations for my present weight of 108lbs (assuming no loss of lean body mass: this will be confirmed/otherwise at my next Dexa scan in 2015).

    BMR is now <900kcals because of my low levels of muscle mass.

    Projected TDEE is approx. 1000kcals on a sedentary day and 1275kcals on an active day (such as one when I kayak for 2 hrs or more).

    However, that’s for my very low Baumgartner sarcopenia score (<5.45 for a woman). However, the Baumgartner sarcopenia score is <7.25 for a man so I wonder if it might be worth you obtaining a body composition report to have some data on whether your skeletal muscle mass is low and this is influencing your TDEE – otherwise, your low TDEE is baffling for someone with your level of activity.

    Hi food2:

    No number I can give you as all are different, not only in TDEE but also in their diets – what they eat.

    If you go to #4 above (TDEE) you can estimate a figure for you. TDEE really determines what your estimated loss might be. For instance, if your TDEE is 2000, you will be cutting 3000 cal. per week from your diet (2 diet days times 1500 per day reduction), and can expect to lose about 3/4 of a pound. But if your TDEE is 1500, then you will only be cutting 2000 cal. per week from your diet, so the loss will be less.

    These small numbers (as opposed to some newbie’s expectations of losing pounds per week) also explain why scales may not tell the whole story, especially at the start. As your body can easily go up/down in weight two or more pounds a day, if you weigh yourself on a ‘heavy’ day you might even show a weight gain when in fact the diet is working just fine.

    You also have to remember that the TDEE the calculator gives is an estimate, not set in stone. You develop an idea of how accurate it is over time. If you follow it strictly and lose weight, no worry, but if you don’t lose, then it is probably high and should be adjusted down to set a new guideline. The one pound a month average includes men, and as the TDEE post explains, men lose weight faster than women.

    Lots of info also in the ‘Warnings’ and ‘Really’ posts.

    Good Luck!

    Ever wonder what would happen if you took a bunch of skinny people and force fed them for a month? This BBC doc answers the question, but may also give you a clue about why you are having weight problems. You may be surprised (and perhaps relieved that it may not be all your fault)!:

    ssure thanks – have not heard of this one but looked at it via the nhs web site and extremely interesting. I am very slight and not very old, but old (59). I’ve definitely noticed a lot less muscle strength. So for me some very good clues here, and some ways to turn things around as well.

    simcoeluv – thanks again for the link. I try to keep up to date with weight loss research and I was aware that examination of large populations of obese and thin people showed nil significance in variables in relation to caloric intake or output. In other words a skinny person could be a couch-sitting junk food glutton, and a fat person could be a celery-eating gym junkie. In that major study there was only one variable that the researchers found was significant, and that was the difference in rate of faecal fat excretion. Interestingly, the use of so-called fat absorbers like chitosan made no difference.

    Certainly there’s more to the equation than calories in/calories out. Really looking forward to watching the whole 58 minutes of the doco 🙂

    Hello Simcoeluv, I was wondering if you could do me a huge favour and answer the following questions with a yes or no answer. I am a lazy reader and you seem to know what you are talking about and I don’t have the focus to read the why behind the what as I am on day 1 and my head hurts hehe.
    1. Is it better to graze on fasting days as opposed to eating two meals? Yes/no
    2. Will starting the fast at dinner time be less effective than starting the fast at breakfast? Yes/no.

    Thanks heaps!!

    Hi Sitash
    If you read the book and watch the program, grazing all day is a no no. Drink water instead.
    Cheers, Bay 🙂

    Q1 No
    Q2 Yes
    Now go and read the book 🙂 P

    Hi Sitash and welcome:

    I don’t disagree with PVE’s answers, but having not seen the program everyone is talking about, I guess I don’t understand the term ‘starting the fast’. So I will answer with a few more words:

    “the way 5:2 works is you go to bed, get up, eat 5/600 or fewer calories during your waking hours, go to bed, get up and eat to your TDEE or less – twice a week.”

    So I would say the fast starts when you go to bed and ends when you get up 2 mornings later.

    Good Luck!

    Just reading the above post about 25% of the TDEE. My TDEE is 1395, so being female on my fast days I should only eat 350 calories not 500? I know everyone can do whatever they feel is right for them but Im just trying to get my head around it. 🙂 And when I said earlier if I lose a kilo I’ll be hooked I dont necessarily mean it has to be a whole kilo, just any loss would be positive for me as mine never seems to shift. 🙂


    We have a large number of 5:2 Newbies. Results have been mixed for you Newbies, but many of you have rejoiced in your initial, large weight losses. Some of you have seen me show up and remind you that much of that initial weight loss is water weight – I am raining on your parade, making you less happy about your admirable weight loss.

    I am doing this so you don’t quit 5:2 when your weight loss slows.

    For those of you not experiencing large, initial, weight losses – don’t worry. If you do 5:2 correctly, you will succeed.

    I have been working with nutrition and weight loss for decades. I have never seen anything as simple, effective and even elegant as 5:2. I am as positively enthusiastic about 5:2 as any poster on this or any other site. So why do I rain on your parade?

    I know that it takes a lot of time for most people to lose a lot of weight. You don’t do it in a couple of weeks or months. You just have to, as SAMM says, ‘Keep on keeping on’.

    Be happy with your results, enjoy the journey, but please, please don’t quit when you hit a plateau or don’t lose weight as fast as you think you should. As I said in another post, a year from now you will have wished you started today. If I would have quit, I would not be down 40 pounds and counting. I have seen reports of people down over 100 pounds on 5:2, but 40 isn’t bad, and I’m not close to the finish. But the finish is in sight, and I know how to get there. You do too, even if you don’t realize it yet.

    Good Luck!


    With a TDEE of 1395 you have a very basic issue of how fast and how much weight you can lose in a given time period. If you look at #4 you will see what I mean.

    The bottom line is you can lose weight on any diet, but slowly unless you starve yourself (not recommended). As the phrase ‘the less you eat, the more you lose’ is operative, eating 350 on your diet days will help.

    I have seen a few women with TDEEs as low as yours, but it is not common. It usually is the case when the woman has very little weight to lose or is extremely short. If neither of these is an issue, I suggest you ‘recompute’ to see if there was an error in the math.

    Good Luck!

    Hi Simcoeluv yes I am short (4ft 10 or 146cm) and weight 60kg. Thats what I put into the calculator and 1395 came up. I am very overweight for my height as I should be about 43-45kg. It says my BMI is 27.8 and my BMR is 1163 (with a sedentary lifestyle). I am a nurse who is on my feet all shift but I dont work everyday and the options state sport/exercise so I just chose sedentary to be on the safe side.

    I also went to the calculator on that myoclinic site which told me 1600 calories. Big difference but Im happy to try to manage which the results from here. Do you have to have the big break in between meals on the fasting days or as long as I stay in the range can I sit/nibble several times across the day?

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