Frequently Asked Questions about Fast-5
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Can I move my window to 3-8 or 1-6?
Yes. Any five-hour window should work. The primary reason for having the window late in the day is to avoid having a time after the window is closed during which one must resist temptations (and limbic hunger) until going to sleep. For some, this presents no problem, while for others, it is a significant one. Fast-fivers have been successful with all sorts of windows, from morning to mid-day to evening.
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Isn’t eating late supposed to be bad?
Eating late in the day is not a good idea if you eat breakfast, lunch, and dinner, because it takes away the last opportunity your body has to reach a long interval of low insulin, as shown in the graph on page 49 of the book. Low insulin levels are good for burning fat rather than storing it. If you’re fasting 19 hours a day, it doesn’t matter whether you eat early or late – your body still gets the opportunity to burn fat.
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I was losing weight steadily for a while, but now it hasn’t changed in the last few weeks. What can I do?
This time of holding steady is called a plateau. Your body has lost some weight, but isn’t willing to let go of more. The following techniques may help you break through the plateau. Once broken, weight is lost at about the same rate as before, and you may reach other plateaus before getting to your goal weight.
Plateau-breaking techniques:
• For a short time (two weeks or so) increase your exercise by 20% or more.Consciously cut your calorie intake for about two weeks. Consistently cutting half a serving of one item in your meal can be enough
• Temporarily cut your window duration from five hours to two or three.If you’re feeling up to it, extend your fast on one or more occasions by 12-24 hours.Try a schedule holiday – a day or two off of the Fast-5 schedule, then return to your usual schedule.People holding at a plateau weight using Fast-5 have reported having increased hunger just before the weight loss begins, so try to think of increasing hunger as a good thing.
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I’ve been on eating on a Fast-5 schedule all week and I’m still eating everything in sight. What do I do?
Give yourself time to adjust. Compensatory overeating is a normal part of the adjustment, and typically subsides after a week, but sometimes it takes up to three weeks. Weight loss is not to be expected until you’ve been on a steady Fast-5 schedule for at least three weeks.
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Is a shorter eating window okay?
Yes. Fast-5 is designed to be as easy as possible and still work. If you find yourself comfortable with a five hour window and want to try a shorter one, or if a shorter window fits your schedule or preferences better than a five-hour window, shortening the window may improve the long-term benefits of Fast-5 by reducing the time that your insulin level is elevated above the fasting baseline.
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Can my window be a different time from day to day?
Success with a sliding window is likely to vary from person to person and schedule to schedule. This is one of the many places where one should start with a fixed schedule, and after achieving a comfortable “steady state” of weight loss, make changes to tailor Fast-5 to schedule and preferences. If your weight loss stops, it’s easy to go back to what worked. If your weight loss continues, then you have found extra freedom in tailoring the program to your lifestyle.
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What can I drink during the fasting period?
Any beverage of zero or negligible calorie content is fine: water, flavored water, seltzer water, club soda, coffee, or tea. Decaf coffee is suggested in order to reduce the stimulant effects of caffeine. See the “Artificial Sweetener” question below for information on artificially sweetened beverages.
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What should I eat?
Decide what you think is the healthiest diet, much like any parent would choose for his/her kids if they would eat anything and everything offered.
– A variety of fruits and vegetables with a generous amount of fiber
– A variety of protein sources: fish, eggs, meat
– Nuts or sunflower seeds.-A balance of carbohydrate, fats, and protein with no extremes. Reducing carbohydrates (bread, pasta, rice, potatoes, cereals) may enhance weight loss by an additional effect on appetite moderation. -
Can I combine this with low-carb (Atkins, South Beach)?
Yes. Fast-5 can be combined with diet programs that specify content, such as a low-carb diet, an ADA diet for diabetics, etc.
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Can I chew sugarless gum or candy?
Sugarless gums and candy often contain calories because they contain sugar alcohols such as sorbitol, so this would not be fasting. Chewing and/or the sweet taste, even without calorie content, may trigger gut activity and increase hunger. If it’s important to you to have gum, you can compare Fast-5 with gum and without gum for a couple of days each way and see if you notice any difference. For candy sweetened with artificial sweeteners, see the artificial sweeteners question.
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How can I see quick weight loss with your plan?
Fast-5 is not a quick weight loss plan. It’s powerful, effective, and sustainable, but it’s not quick. A pound per week is the typical sustained average weight loss. In the tortoise-and-hare tradition, it is more likely to get you to your goal than a “quick” solution. For most people, a pound per week is much faster than the rate at which the excess weight was gained.
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What about artificial sweeteners?
Artificial sweeteners are acceptable but should be minimized. Even though they’re artificial, they may trigger insulin release through taste receptors, which can lead to reduced fat burning. If their use helps with weight loss, then the overall health balance of good vs. bad favors using them, but it would be best to get used to drinking beverages without them.
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What about stevia?
Stevia is a natural non-caloric sweetener widely used around the world. One should not conclude any product is safe simply because it is natural—the deadly toxins ricin and botulinum toxin are completely natural too. Recent toxicity studies have shown no significant threat in using stevia. When hundreds of millions of people have used it thousands of times, as they have with Nutrasweet and Splenda, hidden problems may become evident. Like the artificial sweeteners, the sweet taste may elicit some insulin response, so minimizing use would be a wise choice.
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What about putting lemon juice in my tea or water?
No problem. Not enough calories to have an effect.
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I’m hungry all day some days. What can help?
Fast-5ers report that high carbohydrate (bread, rice, pasta, potatoes) intake usually lead to more hunger the following day. You may want to trim your carbs. Increased hunger may also mean you’re about to start dropping weight again after a plateau period.
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If you ate everything you needed to in order to get all the nutrients you need to survive, wouldn’t you be extremely stuffed?
No—consider this: What do we need nutrients (food) for?
1) fuel – energy to supply bodily functions
2) structure – spare parts to replace what’s used
As for #2, the body is very, very good at recycling. When cells or parts of cells grow old, their parts are largely reused. For someone who is not growing, pregnant, or breast feeding, the need for these spare parts is tiny compared to our need for fuel.
For #1, fuel, yes we need fuel, but if it is stored on our bodies already as fat, then we don’t need to be eating fuel. For those wanting to lose weight, the idea is to “eat” the stored fuel — as Carrie of the Fast-5 Yahoo group put it, she wants her body to go “eat” her thigh.
There is a lot of exaggeration about how much nutrient intake we need to live. Much is due to marketing and some is planned in order to avoid vitamin deficiency. The US RDA, for example, was developed based on micronutrients, not total calories, when obesity wasn’t much of a problem. It used a 50% excess of content to make sure sufficient micronutrients (vitamins, etc.) are available in an “average” diet for the “average” person. -
Can I eat ___________ during the fasting period?
Many people have asked if they can eat various no-carb foods such as olive oil or protein shakes during the fasting period. Eating anything during the fasting period, even if it does not produce an insulin surge, may impair progress on Fast-5 because eating calories of any sort may activate limbic hunger which instinctively prompts a person to eat more once the first bite is taken. Limbic hunger (p. 12 in the book) can be difficult to resist.
However, no two people are alike and what is a problem for others may not be a problem for you. What works for you is all that matters, so you can try any modification of Fast-5 you wish. If your modification works, you keep losing weight. If it doesn’t, you stop losing weight. You can always go back to what worked, and all you risk by trying something new is your rate of weight loss. Once you’re started on Fast-5 using the traditional style (no calorie intake during the fasting period) and see some steady weight loss, you know what works. After that, you can experiment and see what modifications work for you.
See also: Fast-5 Summary, The Skinny on Fast-5
70 comments
Would it be effective to do 19:5 5 days a week with 2 43 hour fasts on non-consecutive days twice a week or is that too rigid?
It’s not too rigid, but it’s fairly austere, so whether it’s right for you or not depends on your goals. It may be a difficult schedule to maintain long-term, but that’s a question of personal fit and whether you’re doing it to meet a short-term goal or a long-term one. It’s also important to remember that a healthy diet doesn’t contain only food; it contains activity (social, mental and physical), so your eating schedule has to balance with those other needs. Can you do that on 19/5 x 5, 43 x2 schedule? I’ve done 43 x 1 as a weekly thing, and it’s been okay.
My question is: is ‘bulletproof’ coffee acceptable before the breakfast? That would be w/grass fed butter and heavy cream, maybe a hint of stevia.
Thank you😊
What’s acceptable and what’s not depends on what works for you. That’s the “study of one.” There’s nothing morally or ethically wrong about “bulletproof” coffee, but when you add fuel to your coffee, that means you’re adding it to your body, so it will burn that fuel before it burns the fuel stored in your fat cells. The oil and stevia are not likely to signal “break fast” to your brain, but in some people, just a spoonful of cream has been the difference in seeing weight loss progress and not. This doesn’t apply to everyone and that’s why what really matters is “Does it work for you?” This concern is addressed in more detail on page 62 of “AC: The Power of Appetite Correction.”
Hi! I just learned about fast-5 and was fascinated by the different benefits it might bring. However, I do not need (and want) to lose weight as my weight is already in the normal range. Can I do the fast-5 diet without actually losing weight?
Yes, many people keep going with Fast-5 after losing the weight they want to for various reasons: they feel better; they save time; they save money; there’s some evidence it may help them live longer.
How do you incorporate weekends off? My doctor said I should stay on 5 hr window during the week and go off on weekends… so confused. If last meal ends at 9 on Friday, when do I eat on Sat? Sun?
There’s no rules set in stone about how you schedule your fast. The only thing that determines whether your schedule is good is whether it works for you or not. If you want to take weekends off, then you would break your nighttime fast at whatever time you did before you started fasting — maybe 8AM for a Saturday breakfast?
Hi. Great books I have read both of them. Even though I’ve been fasting for 10 years now I still picked up a few new tricks and insights. And reflecting on a few things, I’ve noticed over the years, but never could really embrace.
Question 1
how is sleep affected by fasting on a 19;5 program. Do people who have insomnia suffer a little more of insomnia, when fasting for longer periods during the day. Do you know of any research on this?
Question 2
Is there any research on kidney stones and fasting? For example, do some people who fast 19:5 end up with more kidney stones as a result.
Thx.
Mark
A1 – Many people have a transitional change in sleep when they start an IF schedule. This change underscores how profoundly what looks like a minor schedule change can impact our bodies and minds. Changes include vivid dreams, insomnia and increased sleepiness at bedtime (yes, opposite effects in different people).
A2 – I haven’t seen any studies noting an increase in kidney stones. If a person has had kidney stones, it’d be important to maintain hydration throughout the day, since fasting might decrease a person’s usual fluid intake. It may also increase it with the intake of beverages instead of meals.
In your books you mentioned that sometimes adopting the first five can affect your sleep patterns. If so, how long does it normally last for?
Sleep changes typically last for a week or two, and can include vivid dreams, insomnia, early awakening, and other changes.
Can I still do a Fast-5 lifestyle if I am pregnant, focusing on having at least two nutritious meals during the eating window? I never liked breakfast anyway and it’s really easy for me to have a late lunch. Thank you so much for your help.
I don’t recommend Fast-5 or other IF during pregnancy because it hasn’t been studied and determined safe. There no obvious reason it wouldn’t be, but if something were to go wrong, one would have no way of determining whether it was fasting-related or not.
Hi Doctor,
I do Fast 5 and I’m down from 253lbs to 238lbs now in a matter of 3.5 months or so. Right on track I think with your math. I walk a lot now and my eating window is 0900-1400 earlier in the day. (I sleep at 830pm and wake up at 430am) I do cheat on Saturdays generally and have dinner which is usually NOT good for me and a drink or two. Am I slowing down progress just from that one day? Or will that not impact the fasting if I continue with the 6 days a week? Long question short, does this have to be a 7 day a week thing?
As long as you are seeing satisfactory progress (that’s yours to assess, not me), your schedule is great. If progress is slow, it’s still progress and I take the approach of maintaining the livability of the schedule as much as possible. Sometimes that means eating a meal with friends, or going out for breakfast. It’s just a matter of learning what your body does and savoring the times that matter.
Hello Dr. Bert
I already have my “dream body and weight” but i wanted to ask if i keep doing my full body workout 4x a week but instead of eating 3 meals a day and do your method will i loose muscle mass ?
Or should i eat the same amount of protein in the 5 hour window?
I just want to maintain my muscle mass but have the benefits of your method.
I couldn´t find an proper answer for people who are active, fit and also do weight training etc but also maintain the fast 5 method at the same time,
so in short, if i do regular weight training and martial arts, can i do this method without getting”smaller”?
Just for the healthy benefits that comes with it and to maintain my body weight / muscle mass?
Thanks for the reply 🙂
Our bodies are efficiency-driven, so they don’t support muscle mass that’s not used. If you maintain your activity, I would expect your muscle mass to be maintained. Many bodybuilders apply intermittent fasting schedules, so there’s not direct cause-effect connection. Since every body is different, I suggest you verify your own outcome using strength and bulk measurements every month or so. You can compare them as long as your activity stays the same.
Hi!
I’ve been fasting anywhere from 12-16 hours a day for at least 7 years, unintentionally. I just really dislike breakfast. When I attempted actual proper fasting, I made no changes though I was eating clean, low carb and working out much more. My weight stayed the same. I’m going to start 19:5 now, currently 4 hours in, but I’m worried I’ve ruined my chances of successful fasting and weight loss after so many years of so much yo-yo “fasting” and restriction. Is it still possible 19:5 could work for me since it’ll be more hours than my body has done before?
Yes, it’s possible. Some people adopting an intermittent fasting (IF) schedule have had to narrow their window to only an hour (one meal per day, often called OMAD for one meal a day) to see progress. Most, however see results with a longer eating window. Since your typical window has been 8-12 hours, I’d say there’s an excellent chance that with a shorter window, you’ll see appetite correction. It may take a little longer to start with your up-and-down history, but others have been through a similar series of efforts and found very satisfying results with the simple consistency of Fast-5.
Hi –
I apologize if this has been asked already. I searched through all the FAQ’s and wasn’t able to find it. I have several medications I take at bedtime (on an empty stomach). My question: Will this break my fast? My window usually ends about four in the afternoon.
Thank you.
I would not consider medications a break in your fast. Technically, the starch binders could be considered caloric intake, but it’s a tiny amount. If you got to the point that you saw no appetite correction, I might wonder if they were complicating your appetite center’s measurement, but my first bet would be that your body and brain can handle it. There is a lot of psychology behind appetite and as long as you don’t think of it as a meal, or the beginning of one, your gut-brain axis will probably go along with that and do nothing more than it does with water, tea or coffee.
Thank you Dr. Bert for your reply. I believe you have the best solution for the weight reduction, because nothing is off the menu, no cravings. I just started on November 26, eating from 11AM to 4 PM, and it is not hard at all.
Than you again for all you do.
Hello Dr. Bert, may I ask you if you tell us what you eat in your 5 hour window?
It would be helpful just to have an idea. Thank you in advance.
Thanks for your comment/question. I eat mostly vegetables, often starting with a large salad with a variety of ingredients, often including eggs. I occasionally eat fish. Sometimes, when I feel particularly interested in meat, I’ll eat some, but don’t otherwise.
Hi! I just started the 5 hour way of eating and I love love love it. It helps me control my eating and compulsive snacking. I do have a question tho… My stomach starts growling at different times each day and is constant until I eat. I only drink water and lacroix water until my eating window. No coffee or tea. Is there anything I can do or will this get better? I started this way of eating about 2 weeks ago and I’m 45 year old female that has had a full hysterectomy about 20 years ago. No other medical issues. I wanted to start walking but I was afraid it will make my hunger pains worse.
Everyone is different, so I can’t guarantee anything, but if I had to bet, I would bet on it getting better. Your gut has years of experience with a certain schedule, and you’re asking it to change. It’s a primitive system, but complex, so it learns and can be slow to adapt to a new schedule. It does, though, and over the next few weeks, I expect that you’ll see the growls subside. Sometimes consciously reminding your stomach/gut what time you’ll be eating helps. It may sound weird, but the brain and gut are intimately linked. In terms of evolution, the gut came first, so it’s the system on which the brain developed, not the other way around. Distractions of any kind can be helpful, including walking, can be helpful. You’re not telling your gut “no,” just “not now.” Best wishes to you on your journey!
Question I am 54 year old woman who jas been taking Metformin 1000mg for metabolic syndrome fir around 4years, I check my fasting BS every morning at 5am, my 19/5 fasting starts at 6pm and in my 4th week of fasting my BS have been higher than usual like 111,107,105? Why? At 1pm I have a pea protein shake with raw spinach and sugar free coconut milk and than at 5pm a small dinner, drinking at least a gallon of water a day, exercising high cardio have lost 8lbs. Do you think there is something I am doing wrong for my sugars? And my BP is down to 130/70 pulse 50. I am wanting this wait off so bad.
It’s not unusual to see some changes while your body’s in transition. If I were your doctor, I’d be encouraged by the weight loss and keep an eye on the fasting sugars to see what they do when your body’s back to a steady state (when you’re not losing weight anymore). There is a normal rise in blood sugar levels in the morning called the dawn phenomenon that you may be familiar with. This dawn phenomenon rise may be bigger with fasting, particularly with a late eating window, so you may want to experiment with an earlier eating window. Please speak to your doctor about this. Together you can look at the big picture, including your HbA1c, to decide whether your overall metabolic state is improving or not. With the 8 pound weight loss and lower BP, it seems likely, but this decision should be made by you and your doctor, who can see you, knows your history, and can see all your lab data. When the weight comes off, it is likely you will be able to stop the metformin, too.
Hi there, will you please explain appetite correction. I still don’t understand fully. I have noticed since I have been doing fast 5 that when I do eat I just naturally not want as much as I would have in the past.. I eat two meals in my 5 hour eating window, but have noticed that at those meals I am not eating as much. Is that what you are talking about?
Thanks. I love doing this. My window is 11-4. I eat whatever I want at those two meals. I don’t eat sugar or coffee since I cut those out before I started.
Yes! Appetite correction means that you eat the right amount that your body needs. If you have surplus fat, your body doesn’t need to balance every calorie of energy that you use, so you eat a little less. Over time, that adds up to losing the surplus fat. When it’s gone, your appetite remains correct, but with the surplus fat gone, it increases your intake a little so you balance the calories you spend in energy so that your weight stays the same and you don’t lose too much.
Hello Dr. Herring,
I am prescribed a GLP-1 drug for weight loss (I don’t have diabetes). Is there any reason I can’t do the Fast-5 Diet, as well? I will talk to my doctor, of course, but I wanted to understand if Fast-5 might be compatible with someone who is taking a GLP-1 (since both impact insulin).
Thank you!!
If your weight loss is proceeding at a satisfactory pace with a GLP-1 drug alone, you have to evaluate the personal risk/benefit balance of adding an intermittent fasting regimen like Fast-5 with your doctor’s input. There’s no reason I know of that you can’t do both, because GLP-1 drugs are “known” for not dropping insulin too low. However, there are 3 things to consider: (1) The choice to do both must be a decision you make with the advice of the prescribing physician. Your doctor, by seeing you, talking to you, knowing your history, etc., has much more relevant knowledge to help you make the best choice. (2) You may not see any greater effect of appetite correction and no increase in your rate of weight loss with the combination of GLP-1 drug and Fast-5, because they both work to correct the appetite center’s function. Fast-5 may provide other benefits you may decide are worthwhile, including an anti-inflammatory effect, saving time and money on meals, etc. (3) As the recent and accidental discovery of GLP-1 drugs’ weight loss effects shows, we do not know everything there is to know about the endocrine (hormone) and appetite systems. Unexpected, unpredictable (“idiosyncratic”) reactions are possible with any drug. If I were in a situation that prompted me to try the combination, I would start gently, stay on the lookout for problems and report any unusual symptoms I might have to my doctor. In summary, I know of no incompatibility, but it’s unexplored territory. A more rapid journey to your goal must not outweigh your safety. You and your doctor are best equipped to decide if the potential benefits outweigh the risks.
Hi Dr. Bert,
I read through the physiology section in your book, as well as the FAQ here, but I have a question that I haven’t yet been able to find an answer to. Are you able to speak to why the recommendation is specifically for a 5 hour eating window?
Of course, there has been a lot of talk of intermittent fasting diets since the book was originally written, but I’m not aware of any other source that recommends 5 hours specifically. As a point of comparison, I’ve personally seen a lot of benefits with a 6 to 8 hour eating window in the past, so I’m wondering if there’s anything special about 5 hours in particular. I understand the overall benefits, of course!
Thank you!
-John
Thanks for commenting. The reason for the 5-hour window is that it leaves a 19-hour fasting interval. After someone eats a meal, insulin peaks and then tapers off. It can keep dropping for a couple of days if the person does not eat another meal, but almost all (>95%) of the drop (from active to inactive concentration in the blood stream) happens in the first 18 hours for most people. Having a 19-hour fasting interval makes sure that almost everyone taking on the schedule will have a fasting time long enough to drop to their lowest insulin level, which likely helps regulate appetite properly and achieve appetite correction.
Dr Bert I wanted to drop you a note to say THANK YOU. I have, over the some 20 years when I found I had high cholesterol, been using your AC along with changing my diet to eschew statins. I am into my 70’s with rude good health [statin free] but decided the extra pounds put on – mainly due to the aging process I understand – had to go! I commenced AC June 1 and have lost just over 5 lbs. I remember from earlier fasts: the lbs shed do not matter as much as the change in the shape of my body; I am reinvigorated; sleep better; not be concerned when a plateau is reached; not check the scales every day! My clothes just look and feel better. I actually was not sure AC would work for me at this age but I find it the easiest way to look and feel better. Yup. The first 3 days are tricky for me but I focus on other things and stay out of the kitchen. I do take a variety of vitamins – zero meds – and find that taking them with my fast-breaker, saving a couple for evening meal, works well. I point out to friends who are interested in adopting AC but fear they have no willpower that they did manage to stop smoking years ago, thereby demonstrating more than enough self-discipline right there. Keep on keeping on!
Good Day Dr. Bert
My question is how to combine the diet with Sport. Not to eat after äa run or a work out is suppsedly not good for the muscles. I would like to have my 5 hours window between 1 and 6 pm. since i have a family and i enjoy eating together with them. But my time schedule just allows me to work out or run early mornings and i would not want to “spend” my eating window in the morning. What should i do ?
Your answer is very much apreciated!
The key is in your question: “Not to eat after a run or workout is supposedly not good for the muscles.” The research pointing to an increase in muscle growth with eating soon after a workout is based on resistance exercise, not running, and it is a relatively small difference in muscle growth in immediate eating versus eating after a longer interval. It does not mean that there is no muscle growth or no benefit to exercise without eating immediately afterward. The emphasis on eating immediately afterward has probably been exaggerated to enhance smoothie sales in gyms. The small difference in muscle growth may be meaningful to bodybuilders and Olympic athletes, but need not change how or when a person focused on whole-body health and longevity chooses to run or work out.
I have one prescription that must be taken twice a day, morning and night, which would BOTH be outside of any realistic 5-Hour window. The prescription shouldn’t be taken on an empty stomach. I generally do not take it with a full meal of course, but instead a small fruit or a half cup or so of unsweetened applesauce. How could I incorporate this with this way of eating?
Thank you!
Please ask the prescribing physician if you can take the medicine on an empty stomach. Many prescriptions include a recommendation to take the medicine with food because the medicine may cause some stomach discomfort in some people (but not all). Other medicines are better absorbed when taken with food. If you’re not noticing any discomfort when you take it with the small amount of food as you said is your routine, it’s unlikely to cause significant discomfort when taken alone. Your doctor can tell you whether the take-with-food instruction is a suggestion or a requirement. Best wishes to you!
Hi Dr Herring, I’ve been a Fast Fiver since maybe 2008! The biggest change for me was that I became appropriately hungry and then satisfied instead of being hungry all the time. I guess people who don’t experience this have no idea what it’s like to never feel satisfied. So I’m happily eating mostly in a six hour window as that how life works and I didn’t see a weight change between five and six hours (after being on five for years).
The frustrating thing is that after a gradual but nice weight loss, I quit losing after about two years. I noticed that I had about a natural ten pound fluctuation probably with the seasons which is fine. I’m a woman in my 50’s and I don’t have unrealistic expectations of weight, but I wish I could lose another 50 pounds. I’m happy with what I eat and changing my diet doesn’t affect weight unless I really reduce my calories which has me feel too tired and is unsustainable. I’ve also experiment with longer fasts which don’t work for my body although an occasional three or four hour window is ok.
My question is have you come across people like me who seem to have a set point that is a good deal higher than they like? To be honest, I don’t like the weight but I’m okay. It’s not stopping me from enjoying life. Thank you!!!
Yes, some people have higher setpoints, and some have very long plateaus before their body decides it’s safe to drop more surplus, but the first thing I’d look for is a change in stress. There’s a seasonal influence too, which should be wearing off as the days get longer. But back to stress, which is one of the most powerful factors affecting weight loss and gain because it’s linked to real-life survival. In ancient times, it helped protect us from starvation by making sure we ate more when things got tough and didn’t wait until we were actually starving and too weak to find food.
If you look at your recent life and see an increase in stress, you probably have the best explanation of why the weight loss stopped. Your body has no idea what stress means these days—it still thinks you’re either starving or running from a predator. If you identify an increase in stress, you have two general tools: (1) eliminate or reduce the stressor (best, but often not possible or practical) (2) vent the stress through exercise, meditation, yoga, affirmations, etc. I hope this helps!
Dr. Herring, I take vitamins, supplements, and a couple of prescription medications each day. I usually take them in the morning. Some of them do not cause stomach upset, but others do. Would you suggest I take all of them during my eating window?
Thank you.
Yes, as long as that’s compatible with the instructions from your doctor on taking your prescription medicines. Taking some at the beginning and some at the end of the window may be more comfortable than all at once.
Hi Dr Bert
Some clarity please – is the Fast 5 diet a OMAD plan or not?
Gin Stephen’s ‘Delay Don’t Deny’ suggests it is and your book mentions both ‘once-a-day eating pttern’ and also ‘you’re only eating one meal a day, so it’s worth making it a good one!
However, you also state that you can eat whatever you want in the 5 hour window which is where the confusion arises. (I appreciate the need to consider carlorie ‘creeps & bombs’ etc. but are two smallish meals at the start and end of the 5 hour window permitted please)?
Thank you.
James Smith
Thanks for your comment. Fast-5 is not exclusively an OMAD plan, but it’s compatible with OMAD. The basic rule is “Eat within 5 consecutive hours,” so some people choose to eat that as one meal. Others snack, then have a meal. Still others have a meal then snack, some split their intake into two relatively even meals, and some graze through the 5-hour window. From the gut’s perspective, these are all essentially the same, since insulin is not falling back to its baseline level during the window. When I wrote the book back in 2005, I imagined most people would prefer a larger portion at one end or the other of the window, as I didn’t think one would be hungry enough after the first to be wanting the second. However, people have tried it and it works fine. This makes sense, given the gut’s perspective I mentioned above. Many people wind up varying their intake somewhat, both from day to day and changing over weeks to months as they settle into a schedule that feels right. As long as there’s a long interval with a low insulin level from the end of one window to the beginning of the next, it can work. Activities, such as social engagements or changes in work or family schedules can also prompt a change in how a person eats within their window. I hope this helps, and you have my best wishes for your success.
Can I eat 2 small meals during the 5 hour window (1pm to 6 pm)? For example, eat something like a small chicken salad at 1 pm and then eat another small balanced meal at 5:30 pm. Close the window at 6 pm. Thanks
Yes. The basic rule is “Eat within 5 consecutive hours,” so some people choose to eat that as one meal. Others snack, then have a meal. Still others have a meal then snack, some split their intake into two relatively even meals, and some graze through the 5-hour window. From the gut’s perspective, these are all essentially the same, since insulin is not falling back to its baseline level during the window. As long as there’s a long interval with a low insulin level from the end of one window to the beginning of the next, it can work to correct your appetite. Best wishes for your success!
Hi,
I am a 53 year old post menopausal woman and I have accumulated a huge amount of fat around my belly, abdomen, legs. Energy levels are low and motivation for life has decreased. Up until a few years ago I was able to lose weight relatively easily and had a defined waist and abdomen. I have previously been to weight gain clubs like slimming world and weight watchers. Now I look at the changes in my body shape, and what I see I do not like. There is no expectation of gaining my 21 year old body again, just to be able to lose the excess fat gained. I have purchased your book and am waiting for it to arrive, but I am wondering how often I am meant to do this fast? Surely not every day? Intermittent doesn’t mean every day in my head. If you can please advise on how many days in a week to start with plan, (or is it in the book)?
Thanks.
Yes, it is daily. It’s easier than it may sound, and many people are surprised how easy it is after they’ve adapted to the new schedule. Exceptions for special occasions are allowed, too. The frequency of exceptions depends on the individual, and there is no way to know just how often a given person can have a skip day and still see progress—it requires individual experimentation. Some people have been successful fasting only on weekdays and maintaining their usual schedule on weekends, but others have had to be more strict to see progress. You can start with a weekday/weekend schedule if you like, but if you don’t see appetite correction and weight loss after three weeks on that schedule, it’s time to try an every-day plan and see how it works for you. Either way, it takes your body three weeks to adapt and begin correcting appetite, so don’t expect weight loss during the first three weeks of any new schedule. Some people see effects more promptly, and if you do, that’s great, but usually the human body takes some time to adjust.
Is there ANY carb that is OK to eat during the eating period window? Thin rice or corn Stackers that have between 60-100 calories for 4 cakes. What will be the amount of brown rice with lentil portion should be when it’s mixed up? I love bread but can I have some with my meal? how many calories should it contain? and what kind of bread is allowed (If at all) ?
Yes, any carb is ok to eat during the eating window. One need pay special attention to carbs (and consider combining a low-carb or keto plan) only if there’s no progress after 3+ weeks of eating on the Fast-5 schedule (19-hour fast, 5-hour eating opportunity). Minimizing sugary foods is a good idea in general, but most people don’t have to eliminate them entirely to see progress with Fast-5. Appetite often changes after a few weeks to reduce the interest in high-carb/sugary foods, which helps moderate calorie intake and makes sugary items less tempting.
How long can a person stay on the fast five diet? I’ve read conflicting reports about fasting long-term and that it’s not healthy to do so.
It’s funny that someone is being critical of long-term intermittent fasting when there’s virtually no data on humans doing it long-term. I’ve been doing it for over 15 years and remain happy with it. Long-term primate (chimpanzee) studies on intermittent fasting found it either neutral if the primates were fed a healthy diet and better than the control group if both groups were fed the equivalent of a fast-food (high carbohydrate) diet. If you want more information, please cite the source that indicates it’s not healthy to do intermittent fasting long-term. If you mean long-term fasting (fasting for more than a few days, no eating at all) then yes, risks increase with longer fasts. Eating every day (or every other day) and not eating at all for 30 days are clearly not the same thing and can’t be expected to have similar risks.
Anyone who’s following an IF schedule can follow its effects on their health by tracking weight, blood pressure, and how they feel. A doctor can help with other measurements such as HbA1C and HS-CRP. Comparing these values to measurements made before starting IF is the best way to look at its long term effect on you. There is unfortunately no way to compare your own results with what they would have been on a regular eating schedule (unless you have a twin), so we can only compare to where you were before, take aging effects into account, and compare with what’s typical of the general population in your region.
How about alcoholic beverages during the 5-hour window or after the window?
Alcoholic beverages during the window, with usual moderation and with a variety of other foods is fine. Breaking a fast with alcohol (before eating) is not recommended because the absorption may be more rapid than usual. Outside of the window, drinking alcohol would be a fast-breaker, so it’s not on the list of fasting-compatible drinks.
Loved your AC book! I found it informative, easy to read and you’re actually pretty funny 😉
Question/ If longer fasts are more effective for Autophagy, should I try and incorporate (1-2) 36-40 hr fasts/week, appropriately refeed and then do 22/2 the rest of the week? Or am I making this harder than it needs to be and could potentially over fast resulting in a stall? I have less than 15 pounds to lose and a lifetime to achieve the loss. Thoughts?
The benefits and timing of autophagy are not clear in humans. While it seems likely that there is some benefit to longer fasts, we don’t know exactly how much fasting does what. With their long lifespans, humans are quite different from lab animals and may already have one or more of the lifespan-lengthening effects seen in rodent-based studies already in place. My best guess right now to cover all the bases (and it is just a guess) is the longest daily fast you find comfortable with a monthly fast of 3-4 days. While the daily fast comes easily with Fast-5 (19/5), I find that 3-4 day fast hard to schedule and rather boring, so for me, it’s much easier said than done. I often wind up with a couple of one-day extensions (43 hours fasting) instead. Your approach sounds similar. The bottom line is that we won’t know for many years what the ideal schedule for humans is.
If I break the fast for unavoidable social reasons one day, but resume the next day with the usual schedule, will my body need another 3 weeks before seeing weight loss again? If not, how long?
Is hazelnut or French vanilla, black coffee allowed during the fasting window (not with syrup, just flavored beans)?
Thank you!!
Your adaptation doesn’t disappear instantly if you go off-schedule. Most people can have a skip day/special occasion day once in a while and go right back to their regular schedule without seeing a dip in their weight loss. Flavorings such as vanilla beans or hazelnut may be okay for some people, but not for others. Everyone is different, and there’s no way I know of to tell who will have trouble and who won’t. Once you get started and see steady weight loss on a schedule without using flavorings, you can experiment to see what works — and what doesn’t — for you. By doing that, you find the schedule and restrictions that fit your body best.
Hi. I’ve tried intermittent fasting (18/6 and 16/8) but had to stop because it was causing the worst insomnia ever! My doctor said the fat burning was causing the increased energy that was making me manic. What do I do? I really want this to work but can’t live without sleep either! How can I do this if the hunger also keeps me up at night (or is it that I can’t sleep because of the increased energy and then start to feel hunger pangs after 1 or 2 am?). if I could just sleep through the night it would be easy to fast!! What can I do? I really want this to work. (I’m eating protein, veggies, fruit, limited breads, not snacking, getting about 1,500 calories.) Thank you!!
Sleep disturbances when starting an intermittent fasting schedule are fairly common and usually go away within a week, much like the schedule changes encountered with jet lag or daylight savings time changes. If you’ve tried keeping the schedule for more than a few days and the insomnia hasn’t improved, you may want to try a much more gradual adjustment — the progressive start described in AC: The Power of Appetite Correction
In a progressive start, you start by narrowing your eating window only slightly–an hour, or even a half-hour. You maintain that schedule as long as it takes your body to adjust, then narrow your eating window again by the same amount. Then, again, give your body as long as it needs to adjust. Continue the process until you’ve reached your desired eating window and maintain that schedule for at least three weeks to see if you’ve achieved appetite correction. If not, you may need to narrow it more using the same small adjustment intervals. The Fast-5 schedule (19/5) provides appetite correction for most who adopt it, but if you see AC at 16/8 or 18/6, that’s great! When your body’s well adapted to an IF schedule, you won’t feel hunger pangs at night and any that you have during the day are usually much easier to ignore than when on a conventional 3-meal-per-day eating schedule.
Would using a sugar free fiber supplement during fasting time be a problem? Something like Metamucil sugar free
Anything that the body or brain thinks of as a meal can be a problem — for some. That doesn’t mean it will be a problem for you. The only way to know for sure is to try it, because your body, brain, genes, environment, diet, social system is unique. You can avoid putting it to the test by taking the supplement in your eating window. If your goal is to stimulate bowel movements, I’d expect similar results.
Hello, so can I eat 2 meals during the 5 hours or is it supposed to be 1.
Many thanks
How you eat during the window is up to you. People have been successful with 2 small meals and with 1 large one, with other snacks as desired during the window.
hI, can you address the use of coffee in the diet… like having coffee in the morning during the fasting time. I have a a cup of coffee with some 2% milk is helpful for me in a lot of ways. sometimes this is all I drink or “eat” til about 3-4pm. maybe another cup of coffee around 12noon or 1pm. I don’t know if I can go without coffee in the morning): Is it possible to have my cup of coffee with 2% milk and then eat from 4-9pm? I don’t usually have coffee after 5pm not because it keeps me up – it just doesn’t taste right then.
Coffee without milk is flavored water, and any flavored water without significant calorie content is ok. Some people have been successful with cream in their coffee (not milk or cream substitutes, which have more sugar than real cream, which has virtually none). Others have found they didn’t see much progress or hit a weight-loss plateau until they dropped the cream. So, it’s really a very individual thing. If you’re having milk in your coffee and it doesn’t seem to make you hungry during the day, it may work for you. You can try it for a few weeks and see. If you’re not seeing satisfactory progress, switch to real cream and use as little as possible. Try that for a few weeks. If you’re still not seeing progress, see if you can taper off the cream to black coffee and give that a try. I’m not a coffee aficionado, but some brand are bitter and others aren’t. You may be able to find one that has a smoother taste without adding milk or cream. It may cost a little more, but getting to your goal is worth a lot, too.
Hi,
I just finished reading your AC, I am a bit confuse that in the book, you sometimes said to need 3 weeks to check whether the plan suited me (but sometimes at least a month)?
If I try to view the mirror or try clothes to check my slimness, is it anytime ok? If yes, even after meal? If no, what are the best times? What are the “ ‘right time’ difference” between weigh-in and view the mirror for checking the slimness?
In your book, you mentioned that it was good to check the belt (and/or the pants) to see the weight loss change – is it possible that the hole of the belt and/or the belt itself will get loose after wearing it frequently? If so, is it possible that it does not tell the truth of whether I loss weight or not?
Thanks
Weight loss is not to be expected until after 3 weeks, so the fourth week allows some time after that 3-week adjustment period for weight loss to happen.
You are welcome to check your slimness in the mirror whenever you like. There is no best time, but for consistency, it should be the same time each day.
The belt tightness comparison requires the use of a belt that does not stretch. Belts made of leather or other nonelastic material do not stretch enough in typical use to cause a misinterpretation of weight loss. Comparing one day to the next with a stretchy (elastic) belt will not be helpful.