Is Intermittent Fasting Right for You?

Elizabeth Millard
by Elizabeth Millard
Share it:
Is Intermittent Fasting Right for You?

Considered one of the top eating and fitness trends, intermittent fasting sounds like just one more deprivation-driven eating plan that leaves you wistfully glancing at other people’s plates while you hunker down over yet another glass of water. That’s likely because of the word “fasting” right in there.  

But intermittent fasting is more about strategy than starvation. It’s meant to reset your body in different ways, hopefully with fitness and nutrition changes as a result.

Like any big switchover, though, results may vary when it comes down to the individual level. What works for your friends may not work for you, or vice versa. That’s why it’s helpful to play around with variations on intermittent fasting and find what works best for you.

WHAT IS INTERMITTENT FASTING AND WHY DO IT?

Intermittent fasting doesn’t involve specific foods, but rather, a strict schedule regarding when you eat. Also called “time-restricted eating,” the tactic has been praised for its contribution to weight loss, improved body composition, decreased cravings and even athletic performance and endurance. Preliminary research also suggests it may be beneficial for glucose tolerance, hormone regulation, better muscle mass and lower body fat.

Part of its appeal is the simplicity of the effort. Unlike some other trends like “if it fits your macros” plans or keto-focused eating, there’s no calculations to intermittent fasting.

You simply eat within a certain block of time, usually a window of 8–10 hours, says nutritionist and personal trainer Jamie Logie, author of “Taking Back Your Health.” In the other big block of time — about 14–16 hours, including when you’re asleep — you don’t eat anything, not even snacks. You can drink water, coffee, tea or any other beverage that doesn’t have calories.

For example, if you like having a late dinner, you might skip breakfast and have your first meal at noon and your last meal of the day at 8 p.m., and then not eat until noon again the next day.

There are other variations as well, according to Dr. Luiza Petre, a cardiologist who practices intermittent fasting herself and advises the strategy for patients. She notes that some people do the “5:2 eating plan,” which means two nonconsecutive days of a strict 500-calorie diet, and five days of a normal, healthy food. This on-again-off-again method can be tweaked to 7:1 or 1:1, she notes, based on how someone wants to implement intermittent fasting into day-to-day life.

You can also extend your fasting time or do an occasional longer fast, adds Dr. Jason Fung, author of “The Complete Guide to Fasting.” For example, you may eat only between noon and 6 p.m. and fast the other 18 hours. Or you could do a 24-hour fast once or twice a week.

IDEAS FOR GETTING STARTED

“One of its advantages is that it may be added to any diet you are normally following,” says Fung, “including low-carb, ketogenic or Paleo. Although some people have said there are risks, those have been largely myths. Intermittent fasting has been used for millennia without difficulty.”

If you’re new to the strategy, it may be helpful to eat within the typical circadian rhythm and keep eating within daylight hours, says registered dietitian Lauren Harris-Pincus. This can be especially beneficial if you’re looking at intermittent fasting for weight-loss goals.

“We know from extensive research that those who eat breakfast have better metabolic outcomes than those who skip,” she says. “And eating at night can be detrimental to cardiometabolic health.”

The easiest way to try intermittent fasting is to do the most common variation first, advises Harris-Pincus. Determine which eight-hour block of time works best for you, and plan all your meals and snacks to fall within that time frame. Then, fast for the other 16 hours, which includes sleep.


READ MORE > SCIENCE INVESTIGATES: FASTING VS. CALORIE RESTRICTION 


Fung suggests trying that for about a week or so to give your body time to adjust. After that, you’ll know better if you have to tweak your time block to some degree or if you’d prefer to switch to a different variation like the 5:2 eating plan or a similar on-off fasting schedule.

Giving yourself at least a few days — and ideally longer — every time you switch strategies is important because it allows you to see improvements in non-food areas such as more energy, deeper sleep, happier mood and better digestion. Try logging changes like these so you can track what works best for you.

Like any major eating and fitness shift, it can take time to find the perfect fit, so don’t be afraid to experiment with different options — including ditching intermittent fasting altogether if it’s simply not your groove. But if it is, you may be surprised by some of the benefits that come along with the strategy.

About the Author

Elizabeth Millard
Elizabeth Millard

Elizabeth is a freelance journalist specializing in health and fitness, as well as an ACE certified personal trainer and Yoga Alliance registered yoga teacher. Her work has appeared in SELF, Runner’s World, Women’s Health and CNN.

Related

35 responses to “Is Intermittent Fasting Right for You?”

  1. Avatar Bernie says:

    Can a person Cary the time frame?
    One day eat 9-5
    Next day 10-6
    Dependant on social activities

    • Avatar Tinaja says:

      Yes, definitely. My schedule changes frequently. I prefer eating between 11-6, but sometimes I need to eat at 9:30 because I’ll be in a long meeting or have a presentation starting at 10:30. I just adjust my last meal accordingly. Likewise, there are days I won’t get home until after dark, so I eat breakfast later. It’s the length of fasting that matters. It triggers autophagy which is very healing.

      I also like to mix up things to keep my body “alert” and not get too adapted to something to the point that it loses its effectiveness. Some weeks I’ll fast according to sunrise and sunset (circadian rhythm fasting), other times I’ll switch to 14 hrs, 16, maybe a simple 12 hrs for 2 days, then back to 17. I listen to my body. It has different needs depending on my hormonal cycle, the seasons, my activity levels, even if I’m coming down with a cold.

  2. Avatar Judith Finlay says:

    Can my fitness pal be adjusted to count fasting days? At the moment if you don’t eat 1,000 calories or so and you try to complete your diary for the day, it gives a warning about underrating! Seems odd if their now seeing the benefits of intermittent fasting, thanks!

    • Avatar Brian Neary says:

      If you have a premium membership you can set daily goals
      (More-Goals-Calories).
      Otherwise you could adjust your weekly goals, and focus on that rather than your daily numbers.
      Or just focus on your current weekly average. 5:2 might give you 5 days under your goal & 2 days over.

      IMO: If your goal is fat loss/healthy weight, being a little under your weekly goal is okay with Intermittent Fasting so long as the calories you eat are good quality, high nutrient value.
      Achieving Ketosis means your body starts burning stored fat for fuel, so there isn’t an energy or caloric deficit.
      Achieving Autophagy means your body starts recycling old or defective cells into new ones, which again can help negate a reasonable deficit.
      Again, my opinion based on the research I’ve done & my experience so far. I’m still new to this.

      • Avatar Kimberly Garner says:

        Can you still exercise while doing the fasting?

        • Avatar Sue Lash says:

          Yes. and once you’ve adapted to IF, it’s really the most beneficial to exercise in a fasted state. So exercise right before you’re going to break fast.

        • Avatar Lisa says:

          Absolutely! It’s actually best to work out in a fasted state after a certain number of hours (12?) you’re burning stored fat instead of fat from the food you just ate.

  3. Avatar JS333 says:

    I love this plan. I try to keep my schedule the same, 8-6, but adjust as needed. Having said that, if you aren’t eating healthy foods you aren’t going to see much of a difference so I still use My Fitness Pal to count my calories.

  4. Avatar LJ says:

    I learned about intermittent fasting from the book “The Alternate Day Diet” which recommends a partial fast on alternate days and eating “normally” (not actually restricting what you eat) on the other days. The partial fast consists of very low calories based on your current weight, height, and age. For me, the fasting days are 400-calorie days. At present I’m trying to stay at 1200 calories on the alternate days until I reach my next goal and then increase to 1400 or 1500. I won’t stay on this a long time because I would become malnourished, but it has helped me get momentum, which I really needed. I am making all my calories count, eating healthy foods and zero junk except for our monthly ice cream date. I’ve lost 19 lbs in just under 2 months.

  5. Avatar Sandra79 says:

    Can you combine this with calorie reduction? I’ve been doing 1200 calories per day for the past 3 months or so now and I’m liking the results, but I’d like to try out intermittent fasting as well (mostly to get my insulin levels down and permanently reset). Is that still healthy, to eat about 1200 calories on regular days and 500 or so on fasting days? (I’m looking at the 24-hour version, where you eat normally one day, then skip breakfast and lunch the next day.)

    • I’m eating 1200 to 1500 calories a day, and I find that the fasting makes it easier. I’m not sure about the 500 calories on fasting days, though. I stick to the higher calorie count and so far…23 pounds gone.

    • Avatar Logan Miles says:

      I’d recommend combining the 18-6 Fast protocol with caloric restriction.
      Long-term caloric restriction often leads to a slower metabolic rate. IF increases base metabolic rate so the two have great synergy when it comes to weight loss.

  6. Avatar Michelle says:

    My Naturopathic dr recommended this for me. 16/8. It has totally changed my life. My energy level is 100% better, my body fat is lower. My overall mood is great. It also takes a lot of the stress of food prep away. I love it and suggest more people give it a try.

  7. Avatar Grady says:

    I want to start by saying that intermittent fasting is great and has incredible health benefits but there are a few flaws I think when reading this article. First off looking at fasting as a way of weight loss is a terrible way to approach it!! You are taking away 99% of what intermetint fasting is for and you boil it down to one thing of losing weight which is truly just coming from having a healthier body. Intermintent fasting however does not garuntee a healthy body. In fact something that they didn’t even talk about in this article is how to determine if you are healthy enough for fasting. What do you’re hormones look like, do you have a healthy metabolism , what does your exercise look like as far as intensity, how is your sleep, how is your stress in work/personal life. These are all things that need to be considered since fasting is another form of stress on your body and all the other factors should be taken into account in determining if it’s right for you. Second and what I think is the biggest misinformation in this article is the part where it says there is no tracking or calculations needed. If we understand what weight loss truly is, it is a calorie deficit, which means you have to understand where your calories are at and how to cut them. Now if you have been tracking for a long time and paying attention and understand what your calorie consumption looks like then yes I agree you don’t need to track 100% of the time BUT if that’s not the case then nothing is changing. If I eat 3000 calories a day and am not losing any weight so I decide I’m going to cut my eating window down to 8 hours from 12 hours but don’t change anything else as far as from a calorie prospective it’s not going to make a noticeable difference because I cut out 4 hours of eating time.

  8. As a writer who spends most of the day pounding the keys, this was the easiest and most successful method I ever tried. I’ve lost 23 pounds thus far with no craving or discomfort. I’ve always “fasted,” I just didn’t realize I was doing it. So along with making sure I eat healthy foods that I really, really love, this has been a joy, and I’ll probably do this forever without relative ease.

  9. Avatar Lisa says:

    I highly recommend the book Delay, Don’t Deny by Gin Stephens. It’s an easy read and so informative! She also has some amazing Facebook groups which can keep you motivated. If you want the benefits of autophagy, it’s important to fast clean…black coffee, black or green tea, or water only during fasting times.

  10. Avatar JEP says:

    I’m an old man. I hike (or snowshoe or X-country ski) in the mornings. I don’t eat before my hikes. I start about 8:30 AM. The hikes take between 1.25-4.5 hours with elevation gains ranging from 800-2700 feet and distances ranging from 4-10 miles. I don’t eat anything until I get back home from my hike. I didn’t know this was the latest thing but it works for me. It does seem to improve fitness as my time on my standard routes is decreasing while my heart rate is staying the same.

  11. Avatar Sarah L says:

    I feel like this matches my natural rhythm. I’ve never been a ‘breakfast person’ and tend to eat my first meal around 10 am. It’s hard to get the family around the table as early as 6 pm or even 7, but that’s my goal. Even if we eat later, I’ll try to push my breakfast until at least the 12 if not 14 hour stretch. However… I do love my lattes… so my coffee during fasting actually has about a 1/2 cup of soy milk… does that negate the whole effect? I’ll note that I am NOT losing weight, but would like to… (much more that I need to do besides this). Also, I do wonder how in the same article they can say to basically skip breakfast but then also that breakfast is the most important meal for improving metabolism. Why is it that with IF the body doesn’t go into starvation mode and reduces metabolism making it harder to lose weight?

    • Avatar Logan Miles says:

      The breakfast comment was based on research that showed people who skip breakfast are more likely to binge eat at lunch and often choose unhealthy options. It does not slow down metabolic rate but rather makes people more likely to make poor food choices (if you are disciplined this would not apply to you).
      Soy milk will break your fast. Try moving on to black coffee if possible (if you want the benefits)

    • Avatar Evanna Alvis says:

      I love my coffee as well, so I would recommend trying to switch to cold brew during your fasting hours. It’s super easy to make and way less acidic so it goes down much smoother than regular drip coffee. It is the only coffee I have been able to drink without any additives.

  12. There are no physiological advantages about intermittent fasting when it comes to weight loss, it’s just a tool to help people stay within their daily caloric requirement. And with regards to fat loss, that means caloric deficit.

    I’ve fasted daily (16:8 for those that care) for roughly five years now but that’s because it works for my schedule and it helps me from overeating throughout the day – especially when my stress levels rise.

    On those days it’s a struggle to get to your break-fast try coffee, tea and/or sparkling water as they all help with satiety until you get to mealtime.

    • Avatar Logan Miles says:

      That’s not true.
      We know fasts of 16 hours or longer increase autophagy, improve insulin sensitivity and several studies have shown a correlation with increased base metabolic rate.

      • Correct, and I should have been more clear above, those benefits are also present with caloric restriction. Regarding fat loss, IF is just a tool, at this point in the research, nothing more, nothing less.

        • Avatar Ben Richardson says:

          That’s not right, Nathane.

          5:2 dieting consistently demonstrates benefits with increased growth hormone levels, autophagy and insulin sensitivity that are not present in traditional calorie restriction. Also, long term studies show that although overall weight lost is the same whether we use calorie restriction or 5:2, the type of weight lost if different. Around 25% weight lost through traditional calorie restriction is lean body mass, so muscle and healthy organ weight, compared to 11-14% healthy body mass lost through 5:2 dieting. So we lose more fat than other tissue using 5:2.

          Logan is correct.

  13. Avatar Gina Bisaillon says:

    I was doing this without realizing it, unaware that this contributed to my keeping my goal weight for 5 years after losing 45 lbs. Then I read about it and this has encouraged me to keep going. A good trick to avoid eating in the evening is to brush my teeth once I’m done eating for the day because one should never go to bed with food residue in the mouth. Oh and don’t forget the mouth wash!

  14. Avatar Katrina Wray says:

    Its just a shame that the MFP app doesn’t allow you to show that you eat Keto or are fasting. I do a combination of fasting regimes and it would be useful to be able to identify these

  15. […] eating is sometimes referred to as intermittent fasting, but depending who you talk to they’re entirely different. Whereas during time-restricted […]

  16. Avatar Kristen Morich says:

    Incorrect on not tracking. If you exceed your daily caloric intake you will not lose weight, no matter what time of day it is.

    • Avatar MudouSetsuna says:

      Yeah, I’ve definitely binged when I had too much junk under the excuse of ‘it’s ok, I’ll just fast it away!’…. doesn’t work.

  17. Avatar Brenda Kalchbrenner says:

    Interestingly, the article I read right before this one (also on MFP) said that skipping breakfast is “Bad Habit #1 that’s killing your metabolism”. But this article states, “or example, if you like having a late dinner, you might skip breakfast and have your first meal at noon and your last meal of the day at 8 p.m., and then not eat until noon again the next day.” It seems the more info you have, the more confused you become!

    • Just about everyone who writes an article has an agenda. I see articles all the time that have sensationalist headlines, hard stance recommendations, bogus claims and even links to studies that “look” to support their claims.

      How is the general public supposed to know what’s good, bad or ugly? They can’t unless they know how to read research. Look for Randomized controlled studies, meta-analysis or systematic reviews in the title.

      Many of the things you’ll come across can work, and if they fit your lifestyle then give it a try. Once you find something that you think can work, ask yourself, “can I see myself following this diet/protocol/etc five or ten years from now?”

      If the answer isn’t a yes, then you probably won’t stick to it when life gets a little hectic and stressful.

      As mentioned in a previous reply, I intermittent fast but not because of some magical fat loss benefit, but because it fits my schedule and helps me stay within my daily caloric intake. I have many clients who also fast and just as many who don’t and all have the same rate of success.

  18. Avatar Danie says:

    My wife and I have been practicing IF for the past 4.5 years, are hooked and will do this for the rest of our life. We do the time restricted feeding (TRF) version with fasting between 19h00 – 13h00. Our observations to date are:
    1. Significantly increased HDL cholesterol
    2. Significantly reduced Tri-glycerides
    3. Total cholesterol and LDL unchanged
    4. I lost 9kg relatively fast to get my BMI<25. About a year ago, I slowly regained this weight, possibly due to new bad habits with ongoing TRF. I have now started clawing this back again. My opinion is that TRF will assist you to lose weight but be careful, it is not robust enough to withstand bad habits.
    5. Significantly improved blood sugar control – In the past it was impossible to skip a meal and regularly experienced low blood sugar symptoms (shaking, sweating etc). This is now something of the past. I don't find it challenging at all anymore to have extended periods without food.
    6. Strangely enough, both of us experienced an increase in fasting blood sugar levels that we do not understand.
    7. Lower levels of inflammation – this is my perception and I do not have hard evidence to support it
    I find it easy to skip breakfast and to build my fast overnight. This schedule works for us. It is more difficult for us to skip dinner. We became aware of recent research that one should rather not eat after dark but has not yet find a way to incorporate it in our approach.

  19. Avatar MudouSetsuna says:

    Haha, I like how this article outright dismisses keto as an approach, when keto is how I came to intermittent fasting to begin with. Eat low carb and your hunger goes away, you start to intermittent fast naturally. In fact, it’s often reccomended to do both! You don’t HAVE TO, but let me tell you, I always fail at my fasts when I eat junk food. So you can’t just ‘eat whatever you normally do’. You need to eat healthy, whether that’s keto or not, so that you’re not crashing and ‘hangry’ during your fasting hours.

  20. Avatar MudouSetsuna says:

    Autophagy cannot start if you continuously spike your insulin with snacks whenever you’ve started to go into it. You can restrict calories all you want, but have too many tiny snacks late at night even if they are under 100 cal each, and you’re not going to go into autophagy while your body is using the glucose for energy. Autophagy hits after a certain period of not eating.

  21. Avatar Sharon Williams says:

    What does one do if they are on medications that must be taken with food, and must be taken in the morning and the evening (Breakfast and dinner times)? Whenever I try to talk with doctors about intermittent fasting, they quickly dismiss the practice as a negative. Any recommendations as to what I could do to get around the medication issue?

Leave a Reply

Your email address will not be published. Required fields are marked *

Never Miss a Post!

Turn on MyFitnessPal desktop notifications and stay up to date on the latest health and fitness advice.

Great!

Click the 'Allow' Button Above

Awesome!

You're all set.

You’re taking control of your fitness and wellness journey, so take control of your data, too. Learn more about your rights and options. Or click here to opt-out of certain cookies.