I have been doing this since new year and am doing 2 days Monday and Thursday,last meal 8pm then just sugarless tea until 6pm next day when I have a low cal cheese,water biscuits and cherry tomato “snack”after a 40 minute walk home at 8pm I will then have a “Nutriblast”then as I am not a breakfast eater go til early afternoon next day.(i work in a small care home and my hours are 1til 7)weight loss is minimal(I am 5ft6″and currently weigh 9st 12lbs)..the main reason for this post is confusion about how long it takes for the”health benifits to be activated,I have read several times that this starts to occur after 12,hours fasting but reading your post Sim completely blows that out of the water,so am I wasting my time? (I am a 62 year old female)

Thanks Sim,I am mainly doing this for the health benifits and I could do with losing a few pounds but have to be careful at my age because if I lose too much off my face I will end up looking “gaunt”!!..,,,as I find it quite easy to go from 8/9pm to following day at 3 pm with only water and sugarless very weak tea,(18 hour fast) could l do this every day,would it be beneficial to health/weight loss?…..I walk a lot and usually do at least 9000 steps each day,I also go on my vibration plate and cross trainer for about 20 minutes 3 times a week…Have to say I am gutted to read how long it takes for health benefits to kick in especially as I have read posts where people HAVE seen health benefits in a much shorter time frame than you say Sim,it’s all getting very confusing for me….. :(.

Hi Gail:

Guess I don’t know what ‘health benefits’ you have read others are experiencing in short periods of time, other than those associated with weight loss. To determine if 5:2 will reduce the incidence of cancer or heart disease will take decades, not months, to validate. There is evidence it will help diabetes patients, but you have not indicated that is an issue with you.

As I mentioned, you have to decide why you are interested in intermittent fasting. It won’t hurt you, but it takes self control and a certain amount of dietary self restraint. Only you can determine if it is worth it for you.

Good Luck!

The thing about Ketones is the EXCESS shows up in your urine. If you are not giving your body food for fuel it is likely using the ketones you are producing. Thus no excess showing up on your ketostix. At least that’s what was explained to me over a long period of low-carbing.

Making a vague point also to stay hydrated.
Though being fully hydrated won’t help burn or release fat. Being fully hydrated keeps from becoming dehydrated. When we’re dehydrated our metabolism can slow as much as 17% as body starts to conserve it’s resources. So as smith2015 points too. if dehydrated the body may be using or conserving them.

on a personal note I’m sold on the intermittent fasting.
after i adopted the 5:2 for 6 weeks I went on to 4:3 .
though there’s not as much proof that i personally am reaping the benfits. I can say it much better than the diet I used to consume. I have two 27 hour fasts a week now and one 600 calorie semi fast day.

thing is now that i have gotten used to it in 22 months .i feel as if im ready to have the 4 day water fast about every 3 months. So ill be talking to my dr about it.

Thank you both…..

I am still “tweaking” my “plan”at the moment I am doing 19:5 four days a week (the days I work a 6 hour shift at a small but busy care home,no time to think about food!!).. I guess this is a very individual way of eating as has been said before and what works well for one will not necessarily work for others.I lost a pound this week which I am quite happy with.Another concern of mine is that whatever plan of fasting we choose,surely in time the body will get used to it and therefore benefits will in time become negligible,is it a good idea to mix days up a bit?after all I’m sure Stone Age man did not have a regimented eating plan….am enjoying the wealth of opinions and advice on this thread…. 🙂

Have done 19:5 and am finding it quite easy as I don’t really get hungry in the day was going to do it 4days a week but think I can do it every day but will mix the 5 hour eating window up a bit…..

Hi Vickie:

Sorry, you are wrong. The body is designed to run on ketones if it does not have blood sugar, and there is even a ketogenic diet that has been successfully used for over a century for controlling epileptic seizures. There is absolutely no harm to the body from ketones generated from burning its own fat, or from eating a high fat diet. It appears the brain may function even better on ketones than it does on glucose!

You might watch this for some basic information, although it covers much more than ketones: https://www.youtube.com/watch?v=OFD2q5iqevY

Good Luck!

Hello Muddyone, It takes about 3 and a half days practically without carbohydrates for the ketones to show up in the testing strips.

Hi Vero:

Before I answer, I have to point out I am not a typical dieter. Although I am overweight, I have no particular interest in losing a certain amount of weight or losing weight in a certain timeframe. I travel often and make no attempt to diet when traveling. Additionally, I am as much interested in 5:2 from a research point of view as anything else. The 5:2 sites provide much helpful first-hand information from both people coming to 5:2 for the first time and from those that have ‘stuck around’ long enough to lose a lot of weight and are trying to figure out how to maintain their weight losses. In addition, many people collectively know more than a few, and I am able to pick up information I may not have found or found quickly from others who are kind enough to post new studies they have run across or articles about emerging issues in diet and nutrition that appear in publications around the world.

With that said, my interest in 5:2 started in early 2013 after seeing a five minute clip of Dr. M explaining the basics of 5:2 on a TV program. The weight loss concept was so simple and scientifically solid I immediately wondered why I or someone else had not thought of it decades earlier. I began doing 5:2 the next day. Over the next two years I lost 40 pounds. In 2015 I decided to experiment personally with weight maintenance and tried various fasting methods to determine which seemed to work best for me. At the end of 2015, I was one pound off my Jan. 1 starting weight and convinced that weight maintenance was easier using fasting concepts than it is with any other diet (or way of eating) I have studied. I have just returned from some travel and am going back on 5:2. I would like to lose about 20 or so pounds in 2016. My schedule will have an impact, but I have no doubt I can do it if I want to.

5:2 is not easy to do, but it is so simple that I am often saddened by all of the other confusing variations of IF people constantly propose. Many newbies get confused and fail as a result. I am intrigued, however, by the seemingly large number of people that return to 5:2 after trying it and stopping for whatever reasons. They seem to understand it works and they can do it. I hope in the future more and more come to that basic understanding – it works and they can do it if they want to. Until that ‘magic pill’ shows up, I think 5:2 is the best option of all of the diets out there and does not to be ‘supplemented’ in any way to be more effective. It is fine just as it is.

Heron,

I’d sure be interested to hear your results after a fast day. I’ve been doing two 48 hour zero calorie fasts a week for about a month and am curious if that’s long enough to go into ketosis. Every week I try to do 4 days in a row but haven’t been able to make it past 2.

Bronx

Hi muddyone (and Bronx),

It would be unusual to go into ketosis by the end of 24 hours unless you are really exercising a lot or are on a carb restricted diet. Especially if you had a large dose of carbs beforehand (i.e. home made chips). Maybe if you severely limit your carbs the day before you fast and eat mostly fat and protein, them maybe you will go into ketosis sooner. I do two consecutive days on Monday and Tuesday with zero calories. So my last meal is 6pm on Sunday and the next one is 7am on Wednesday morning. By Tuesday morning 36 hours fast Ive got a ketone reading of about 0.5mmol/L. By Wednesday morning prior to eating breakfast, approx. 60-61 hours fast my reading is 2.3mmol/L.

I don’t think you have to go into full blown ketosis to get the benefits of this diet. If you REALLY want to get into ketosis then there is no short cut. You go zero cal for a couple of days or you go on a very carb restricted diet 24/7.

Im not advocating either by the way. Everyone finds their own happy place using 5:2.

Bronx just by one of the many glucose and ketone meters that are on the market. Ive just recently bought one and they are better than using keto-sticks if you want an accurate number rather than a colour change. The meters aren’t that expensive.

I need clarification!!…..l have reached my goal weight and now do two back to back days with only a 500 kcal meal in the evening….(and that is mainly for the health benefits claimed in the MM book)From what “sim” is saying what MM wrote in his book about health benefits (little mechanics basically sorting things out in a relatively short fasting zone including cancer protection) is not true!!!……IF l have to do a 4 day water fast to achieve this then the information in the book is just wrong!!!

I am surprised so many people on the site are talking about ketones.
This was the centre of attention for the Atkins Diet. We are on the 5:2 site, which is focusing on a different method. Naturally, you have to wait until the food you have inside you has been digested before going for more, but I don’t think all this worry about ketones need be part of doing the diet for the long term. It is about naturally restricting what you eat without even thinking about it, not measuring calories, and just living a normal life.

Hi Bronx,
I think practically all of us in this forum have a mental image of ourselves that others may not necessarily share. We all hate the look of extra fat hanging over our belts, and have tried for years to get rid of it. Knowing that conventional diets do not work, we are all going for this last chance effort to be freed from persuasive negative thoughts about ourselves. I am treating this as an all out last ditch effort, after which, if I don’t succeed, I will give up for ever. (and buy a plain BURKA for day, and a sparkly one for evening wear!).

Hi Gail:

5:2 has been proven to be a safe and successful way of losing weight, and you seem to be an excellent example! All I have said is there is no proof that 5:2 provides health benefits other than those that normally come with weight loss. However, those benefits are substantial! Further research may show other benefits, but I am not aware of such research at this time. Nor am I aware of any research that shows any other IF regime provides more benefit than that coming from weight loss.

One problem with proving other benefits is that all IF regimes allow people to eat whatever foods they want to eat so the variations are infinite. How can you prove that 5:2 does this or that when one person successfully doing 5:2 eats nothing but low fat sugar filled products and another eats high fat very low carb products and yet another only eats vegetables? The variables are way to great in number and food content types to possibly sort them all out. The impact of the food being eaten in the diet could easily overwhelm any impact of not eating for a couple of extra hours a day or a week.

So it comes down to belief. If you think eating the way you are eating is healthy and helpful, do it! If you don’t, find what you think is a more healthy way for you. But please don’t go back to eating the way you were eating and regain all of your weight. 5:2 is a long term way of eating that provides proven health benefits that normally come with weight loss like lower blood pressure, better cholesterol levels and lower triglyceride levels. There is absolutely nothing wrong with those kinds of outcomes!

Good Luck!

Vero, I’m certainly not worried about ketones. I’m simply interested to see at what stage of fasting I approach ketosis. As I said, I think it may act as a small encouragement to fast longer and more strictly. I’d also like first hand proof that ketosis isn’t going to happen in a day as many people mistakenly think despite the wealth of information available.
The strips aren’t the greatest indicator anyway as they only test for one chemical and the colour will be darker the less hydrated one is but it will be interesting nonetheless.
I’m not expecting a reading of 1.5mM before at least 48 hours of water fasting.

As an aside, I have no interest in 5:2 until I reach my maintenance weight (or shape, more accurately). Until then I’ll stick with the far quicker, and just as easy, ADF upon which most of the science of 5:2 was based.

Simcoeluv,
I had to smile. Your response sounds like the man who said “I thank Thee, Lord, that I am not like other men”.

Heron, Well done! Two stone is a lot in 4 and a half months.
I have 10kilos to lose. I have only had vegetable soup today, and coffee.

I just got results back from a blood test I had done as part of my annual physical exam. The test was taken after about 60 hours of fasting, and on the chart Ketones are out of range, 2+, which I assume is a good thing.

I had the exam yesterday and went through the report with my doctor. BP is great, cholesterol is “Out of the park” great and most other tests are either normal or out of range on the good side.

One thing my doctor is a little concerned about (but not too concerned) is that my sodium level is low. He thinks I might be drinking too much water and asked me to back off a bit. I’m mentioning it here for others to remember you don’t want to drink too much water; too much of a good thing can be as bad as not enough, so be careful.

Bronx