Intermittent Fasting for the Vegan Athlete: Is It Right for You?

Intermittent fasting is all the rage—but is right for you?

Fasting has long been a common practice in many cultures, used to promote mental health and longevity. More recently, it’s gained popularity as a weight loss tool.

But significantly restricting your calories for a long period of time can be dangerous. Not to mention incredibly difficult, scary, and simply not fun.

That’s where intermittent fasting comes in. Intermittent fasting refers to dietary patterns that cycle between fasting and and non-fasting, to help you experience the health benefits of fasting without many of the downsides.

And studies have shown that it can help you lose weight, boost your metabolism, reduce the risk of certain diseases, and even improve your mood.

The best part? Intermittent fasting is completely natural.

According to a 2014 article in the journal Cell Metabolism authored in part by Valter Longo, the director of University of Southern California’s Longevity Institute, intermittent fasting may act as a low-grade stress, which triggers the body’s cellular defense mechanisms, repairing damage and fighting disease.

It’s a tool that helps to trigger our bodies’ own natural healing processes. And speaking as someone who has practiced it for over five years, I can tell you that it works.

 What is Intermittent Fasting?

Before we go any further, it’s important to explain what intermittent fasting actually looks like. It’s confusing, in part, because when people refer to intermittent fasting, they could be talking about several different approaches:

  1. The 16:8 method where you eat within an eight-hour period each day and fast for the remaining 16 hours. When you’re fasting you can’t take in any calories, but you can consume non-caloric beverages, including coffee, herbal tea, water, and sparkling water.
  2. The 5:2 method where you eat normally for five days of the week, and restrict your calories to 500 (women) or 600 (men) the other two days.
  3. The eat-stop-eat method where you do one or two 24-hour fasts each week; for example, not eating after lunch until lunch the next day.
  4. The alternate-day fasting method which involves eating normally one day, and then eating very low-calorie (500 calories) the following day.

As you can see, none of these calls for more than two days of complete fasting per week, and most allow for calories every single day.

In my opinion, as long as you stick to one of these four options, there’s no wrong way to approach intermittent fasting. Which option you choose has more to do with your preferences and needs, but I’ll get to that in a few minutes.

Intermittent Fasting on a Whole Food Plant-Based Diet

If I were to poll ten vegans about the ideal diet, I’m willing to bet at least nine of them would say “whole foods plant-based.” In our circle, the whole food plant-based diet (WFPB) is what most of us strive for.

It’s the top dog. The (vegan) crème de la crème.

But for some of even the strictest WFPB followers, it may not be enough. They may still struggle to find their ideal weight, or want to take their diet one step further.

I’ve had many people come to me in my practice and say that they feel they must be doing the WFPB diet wrong. That despite following it (and feeling great), they can’t seem to lose the extra weight. That’s relatable, because that has also been my own experience.

Even though I eat a WFPB diet—with the rare vegan treat, of courseand I am very active, I still have to rely on intermittent fasting to prevent weight gain.

But how do they work together?

As a vegan Registered Dietitian, I’ve see many people in my practice get the benefits of a WFPB diet combined with intermittent fasting. In fact, combining WFPB and IF is a highly anti-inflammatory way to eat, and may reduce your risk of disease even more than either approach can on its own.

5 Great Reasons to Consider Intermittent Fasting

Now that we know what it intermittent fasting is, and that it can work together with a whole foods plant-based diet, let’s talk about the why. That is, why intermittent fasting may be right for you.

Here’s what we know:

1. It’s simple. There are no extra supplements to take, and your meal prep and planning will be simplified because you’ll eat less often. As a result, it will likely reduce your food costs too.

2. It is effective. Intermittent fasting can be just as effective (if not more effective) as calorie restriction in promoting weight loss.

On top of that, studies have shown that intermittent fasting may:

3. Improve your mood and your focus. I know some of us get hangry when we don’t eat, but, with a little practice, fasting can actually improve your mood and focus. In fact, intermittent fasting may be successful in helping to treat depression.

4. Help you lose fat while preserving muscle mass. Unfortunately, when we lose weight, we don’t just lose fat, we lose muscle too. But intermittent fasting is more effective than calorie restriction at preserving muscle mass during weight loss.

5. Reduce your risk of disease, and possibly help you live longer too. Calorie restriction is one of the few things that has been proven to extend lifespan. Interesting … but are you now just going to be hungry and miserable for a longer period of time? intermittent fasting helps to alleviate that concern.

Some researchers argue that you can get may of the same benefits through periodic restriction, like intermittent fasting. It may also improve insulin sensitivity, reduce inflammation, and reduce risk of diabetes, cancer and heart disease.

Weight Loss Results: What to Expect

Weight loss with intermittent fasting is similar to the results with calorie restriction. If you are consistent, you can expect to see a loss of 1 to 2 lbs per week.

For some people, intermittent fasting may appear to work much better than calorie restriction or other similar methods, however this is likely to be because you’re able to be more consistent with it. I hate to break it to you, but if you’re not consistent, just like with any other diet, it won’t work.

Think of intermittent fasting as a lifestyle change, not something you will just do for a few weeks to get to race weight or to fit into a bridesmaid’s dress. It’s something you can do for life—just like going plant-based or picking up running.

When you reach your “happy weight” you can maintain it by fasting less often, or in a less restrictive window. This is what I do, and I love the results.

Who Should Try Intermittent Fasting

I believe that most people can benefit from some form of intermittent fasting, and that some people seem to really thrive with it.

If you’re an “all or nothing” person who finds moderation challenging (just how many vegan brownies is a once-in-a-while treat?!) then intermittent fasting may be perfect for you. That is one of the many reasons I myself love it.

It just makes eating and meal planning and snacking simpler. You’ll need to organize and prepare fewer snacks and meals and that reduces decisions and time spent in the kitchen.

And who knows, you might just save some cash too.

But Proceed with CautionIt’s Not for Everyone

Have I sold you on intermittent fasting yet? Before you dive in, let’s make sure it’s a good fit.

Fasting is not for everyone. It’s not a good strategy for if you are diabetic and take insulin, or if you are pregnant or breastfeeding. People who have a history of an eating disorder should be cautious with fasting because it might be a trigger for them.

Or, if you’re just the type of person who gets really hangry when you don’t eat (yeah, you know who you are), you probably shouldn’t practice intermittent fasting. If not for yourself, then for the sake of everyone who has to live or work with you.

Finally, some people just don’t like fasting, even after getting used to it. And if that’s you, that’s okay. Good for you for giving it a try.

How to Get Started with Intermittent Fasting

When I first tell most people about intermittent fasting, their eyes glaze over thinking about all the rules and complications. But it’s a lot simpler than it looks, as long as you’re smart about your approach to getting started.

1. Make a plan: For fasting to work it will require structure and rules, because as you can guess, there are times when it’s going to be hard.

But there are a number of ways to set those boundaries. When trying to select which protocol will work for you, follow your instincts. People usually have a sense of what might fit well into their lifestyle, and for some, trying to eat only 500 calories in a day seems too restrictive and they would rather try eating within an eight-hour window using the 16:8 method.

It’s less about which is best, and more about which is sustainable.

2. Ease into it: Going all-in on day one could result in no day two. Ease into it.

For example, It‘s fine to start with a twelve hour feeding window (say 7am to 7pm) and then move to a ten hour window before ultimately dropping to that eight hour window when you’re getting in that day’s calories. If you start with eight hours right off the bat, chances are it will be too hard to sustain.

3. Set a target: Like with any health and lifestyle improvement, intermittent fasting takes some time to have an effect. It is important to give a good try before deciding if it works for you. Set a target of trying it for 30 days.

Although fasting can be difficult at first, many people actually report that it gets easier with time. And after your target date, if it is not working out, don’t feel you need to give up on fasting entirely. You can always experiment with a different fasting protocol.

4. Plan to succeed: Meal planning while fasting? I know, I know …

But I still recommend it. We often make healthier choices when we plan in advance and have all the ingredients we need on hand; even better if we do some of the prep in advance. This is particularly important when you are fasting, because once your feeding window opens you’ll likely be hungry and want to eat whatever is fastest.

Instead, you should be focusing on healthy, fiber-rich meals that will sustain you when you are fasting.

My Top 3 Tips for Success

1. Don’t be afraid of a little hunger. Hunger tends to come in waves, and even if you are feeling very hungry now, you might not in 30 minutes if you can keep busy and take your mind off of food.

Many of us have become accustomed to continual snacking, and that is a habit that we need to break if we are to become successful at intermittent fasting. We can use our energy stores to support our activities when we are not fueling, and that will help us burn fat.

Of course if you are feeling lightheaded or can’t concentrate, it’s time to break your fast.

2. Stay hydrated. You will find fasting much easier if you drink lots of water or herbal tea. People often mistake the feeling of thirst for hunger, and drinking will keep your hands busy and help you feel fuller.

3. Once you know the rules, you can break ‘em … a little. One of the great things about intermittent fasting is its flexibility. If you are following 16:8 and your usual eating window is between 11:00 am to 7:00 pm, and you know you are going to a party in the evening and you would like eat and drink at that party, then you can adjust your window to later in the day: say 2pm to 10pm.

You could also try for a less restrictive window that day, like an eating window of 10 or even 12 hours. Finally, you could just take a day off from fasting. If you were faced with the same situation and you follow the 5:2 pattern, just move your fasting days around so they don’t fall on the day of the party.

Training while Intermittent Fasting:

Okay, now to the question I’m sure all No Meat Athletes have in the back of their mind: How will this affect your training?

Intermittent fasting can be successfully combined with running, swimming, walking, zumba, martial arts, Crossfit, and just about any fitness activity. We have enough glucose stored in our liver to support moderate intensity activity for 90 minutes or so, and 30-60 minutes for high intensity. You can do these workouts without fueling.

Keep in mind, however, that not fueling may impact your performance. If you find that’s the case, try doing your workout during your eating window or on non-fasting days. You may also decide that for the moment weight loss is more important to you than gains in performance. For most people the difference in performance with or without fueling on shorter efforts is marginal. Give it a try before deciding that you need your pre, during, and post workout snacks.

The one possible exception to this is long efforts.

If you are a marathon or ultramarathon runner or a distance cyclist, and your workouts last several hours, you will almost certainly need to fuel during those workouts. In that case, try to workout during your eating window, or don’t fast on the days when you do your long run. If that seems impossible to coordinate, then maybe intermittent fasting is not for you. You can perhaps try it at a later time, when your race goals and workout plan has changed.

Ready to Start Fasting?

I’m the first to admit that the idea of fasting can seem a bit crazy—even scary.

… What if I’m hungry all the time?

… Will it leave me tired and weak?

… What will other people think?

Intermittent fasting can take away many of the concerns around fasting because it offers so much flexibility, while at the same time acting as an effective health tool.

If intermittent fasting sounds interesting to you, give it a one month try and see what you find. It could but just the boost you need to drop a few pounds and jump start your long-term health.

About the Author: Pamela Fergusson is a vegan Registered Dietitian with a PhD in nutrition. She and her husband Dave have four children, and she loves to speedwalk ultramarathons. Read her nutrition blog and find her on Facebook.



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  1. I tried the 8:16 method, and actually found as a 48 yr old woman that i could go 14:10, 9:15 and 8:16 and still get great results. My last remaining vice is plain , natural potato chips (otherwise it is WFPB eating with no refined sugar) and I was still managing to gain weight ( slow metabolism – medically tested and proven) and I.F keeps me at a healthy weight.

  2. I was WFPB for over a year and WFPBNO for over 7 months but couldn’t shake my extra 20 pounds. I even stopped drinking the occasional glass of wine and beer, but that didn’t help either. 5 weeks ago, I started a plant-based 5:2 intermittent fasting plan and I’ve already lost 12 pounds. I’ve also found that it makes me less hungry and more aware of my mindless boredom snacking on non-fast days. It has also cut down on our food bill and number of weekly trips to the grocery store. That was an unexpected, but welcome side-effect. It’s working great for me and it was much easier than I expected it would be.

  3. Just wondering if this can be done long term? Also wondering, if anyone uses this to maintain their current weight?

    • Hi Alicia,

      Yes, this can be done long term. I am using fasting to maintain my current weight. You can just extend your eating window a little, or fast fewer days per week.
      Great question!

  4. S. Downs says:

    This is the breakdown article I’ve been looking for! Thank you!

  5. I like to do two days of sensible but adequate eating (for back to back powerlifting days) & then back off for GPP / cardio day & repeat – works to maintain & grow muscle, increase strength & reduce fat at a sustainable rate without any hardship

  6. Sharyl Masuyama says:

    Nice write up. I am going to try IF for 30 days. I just did a 10 day detox from social media, alcohol, processed foods and oils. Feel great and wanted to continue with a little more challenge. What you’ve presented here seems like a smart approach and very doable. I have a dinner date with a friend, then focused forward I go with IF (16:8 method). Thank you for sharing this. Aloha! 🙂

  7. Thanks for this. All really interesting.

    Do you think this works equally well if you change your “Food window” times every day, according to activities? I’m a personal trainer, and sometimes have clients from 6am, but sometimes from 10am. Other days (as an ultra runner) I might have a training run that begins at 4:30am and lasts until 9:30am. Obviously, the demands on my system on these different days don’t fall within the same times! Having said that, I find it relatively easy to eat only within eight-hour windows, most of the time (except possibly on ultra-distance days, when replacing fuel used can be tricky even over a longer time.) Would it still be as beneficial to my body and mind, if my food window was, say, 5:30am-1:30pm on one day, then on the next, from 9:30am-5:30pm and so on?

    • Hi Ruth, Yes, that is still beneficial. The key is doing whatever will work for you on a consistent basis – even if that consistency varies from day to day. Good luck!

    • Great questions! Some days for work I am up at 4:15 and other days I’m working till 2 am. I also run and cycle – this is a perfect articke for me to read. I am in my first week with this. Also trying to follow no flour sugar or snacking.

  8. I have a thing with being hungry. I hate it! I fear it. So this would probably be good for me because I eat often. Any tips for sleeping on an empty stomach? Is it something I’ll get used to?

  9. Thank you for the article!

    I would like to do some form of IF, but I don’t know which version to try. I have thyroid issues, and don’t wanna mess that up with longer fasts. I already do about 14 hours between supper till 8pm and breakfast around 9-10am. Also I find it it really hard to workout or to do my job (sedentary) on an empty stomach. I should add that I eat WFPBNO so I guess this is already a very clean diet. My motivation is to lose the last 12 pounds that I cannot shed and to improve energy levels rather depleted last year. Any tips for beginners? 🙂

    • I also have thyroid problems (hypo). You are almost there! 14 hours is so close! I have just started skipping breakfast (since we have to wait to eat after we take our medication anyways!) so I have time to process the meds. Drink a lot of water! It helps curb the hunger (and usually when you feel hungry your body is really trying to tell you that you’re thirsty). I have been doing this for about a week and I really feel great! Good luck! ?

  10. Should I stick with a certain amount of calories in the 8 hour window? I’m looking to lose 30 lbs and was thinking about eating 1200 calories within the window.

    • Yes. Since you are looking to cut (i.e. lose weight), find out your TDEE calorie amount, subtract it by 500 cals, and eat that amount of calories during your eating window. For e.g. your TDEE is 2500 cals. You need to eat 2000 cals or below during the eating window to lose 1lb of weight per week. If you eat more than 2500 cals during the eating window,you will still put on weight. The eating window has to contain the right amount of calories to support weight loss. What IF does is, it shrinkes your eating window and gives more calories per meal to ensure that you are satisfied while eating within your required range.

  11. Awesome article! I’ve gone from 330 pounds down to 280 pounds in 2 months. I’ve gone full vegan and daily strength training followed by hiking or kayaking. I do the 16/8 method and works great. I’ll have a decent size lunch of brown rice, salad and baked veggies. For “dinner” ill make a green packed veggie & fruit juice. That holds me to the following day around 2pm.

  12. Hi I have ever a question.
    I’m doing the 16:8 with vegetables and fruits with lots of water and tea. I’m eating them through out my window and juicing like small mandarin oranges in my juice of celery and carrots. Will this hinder me from losing?

  13. Sonia Gomez says:

    If I want to do the 16/8 method and my last meal is at 7
    Can I have a green juice en the morning or that’s considered as meal and break the fast ?

  14. To try to lose weight should this be done everyday or how many times per week approximately?

  15. I have heard that women should be more careful with fasting. As someone with PCOS and a 10 year vegan (low fat, no added sweeteners including no stevia/maple syrup, almost 98% WFPB) who has 150 lbs to lose, I worry about messing with my hormones. I’ve been playing with this for about a week doing the 24 hour window on some days and the 18 hour window on others. I really like not eating breakfast and have found the 24 window isn’t so bad. I just don’t want to make sure I don’t screw myself up.

    • I have problems with hormones as well – hypothyroidism and take BC for cysts, which has resulted in mild depression. I’m vegan and started IF more to build muscle and lose extra fat and have reaped a ton more benefits – depression has been helped a ton and energy levels have increased. I think everyone is different, so if it’s been working for you definitely continue!

  16. Bailey Elliott says:

    I have been trying IF for the last week, and was surprised at how easy it was to skip breakfast. I grew up with “breakfast is the most important meal of the day” adage, but I am learning that this may not be the case. I have been watching videos on YouTube from a doctor who promotes IF on a ketogenic diet (high fat), and Keto only, as if it’s dangerous to consume any more than 5% of your calories from carbs. That got me worried due to the high level of carbohydrates we WFPB eaters consume. So, does anyone have any thoughts or opinions on the subject?

    • Iwan Effendi says:

      Hi Bailey,
      In my experience high carb low fat diet (I believe vegan diet falls into this category) just works very well. The most important thing is the total calories. In fact, I believe ketogenic diet is bad in long term for the kidneys and liver.

  17. Eliot W. Collins says:

    I’ve been doing intermittent fasting for many years. When I started, it was just called “skipping breakfast”. Now I typically “fast” between 9:30 p.m. and 11:00 a.m. I always start races on an empty stomach as well. Does it get me into “fat-burning mode”? Who knows? So far. so good.

    • Hey Eliot. I wouldn’t mind some advice on this. I am an emerging long distance runner. I always did 5 and 10k’s but took on the challenge of a HM a year ago and this past December did my first Marathon. I’m still running and working to improve speed, endurance and what not. I am a vegetarian – but, I am a believer in eat to live not live to eat and really feel I don’t need to eat 5-6 small meals a day. Any advice you an give me for the 16:8 method for an endurance athlete? I am also training for a triathlon in October and another Marathon in December. Any advice would be great!

  18. I’m a big fan of IF. Been doing it for a little over 5 years using the 19/5 window. I train daily for 1-3 hrs in a fasted state and my body performs better than in a digestive state. Anything over 3 hrs of intense exercise and I’ll introduce calories.
    I’m also a vegan, 90% WFPB. I’ll be 48 this year and feel and look great. Not sure why people feel hunger doing IF…after the initial 3 week transition I never had another hunger pang. That’s for the write up!

  19. is the water with fresh lemon juice ok?

  20. This is great!! Thank you for the helpful tips! I’ve done the 5:2 diet for a year (started this 3 years ago) and lost about 30 lbs on that and before fasting, I only lost 14lbs with a calorie deficit and training. So I have collectively lost 44lbs and I’ve kept off the weight for 3 years now. I’ve been up and down my whole life with extreme weight loss or gains and nothing has helped me or made me feel as good as intermittent fasting. I no longer do the 5:2 diet since I just want to maintain and had gotten too thin at one point but I maintain now by fasting 16:8 and some days 14:10 and I am completely vegan. For a while, I was fasting too much and not eating enough during my window and it would really mess with my hormones and liver. I found that 4-5 days a week or fasting is perfect for me and my hormonal balance and on the weekends I just eat healthy and work out of course (crossfit 4-6 times a week). I feel great, fit and a super strong athlete for 5’2 and 108lbs and I think any form of fasting is excellent for anyone, plant-based or not. I feel better than ever! Thank you for this article, it’s extremely helpful! I will share this with many. 🙂

  21. Would you recommend intermittent fasting for gaining muscle mass?

    • When done correctly it is perfectly fine. Muscle mass gain comes from nutrition, resistance exercise, fat burning, etc. So yes, many athletes (including vegans) use IF to increase their performance at the gym.

  22. Would this be a good program to lose a lot of weight? I have about 60 extra pounds that I would like to lose.

    • Most certainly a good and natural program to follow, provided that you don’t have any pre-existing conditions (upon which case you may want to consult with your doctor first). Otherwise, it’s a great way to achieve those goals and get rid of those 60 pounds! The fundamental key is to come to the true belief in your 6th sense and brain that you are “not” following just another diet, but that you “are” changing your life-style.

      From that starting point you could lose a pound a week and in just over a year those 60 pounds are gone. Imagine, just one year from now you could be your new you!!

      Want to speed it up a bit? Try straight 3 day water only fasts every month, and see if you can build up to a 7 day water fast by month 6 or 9. Continue your Intermittent Fasting thereafter and you’ll see amazing changes in your life.


      By the way, this is exactly what I did to loose 60+ pounds. I’m a male, 42 years old, 6′ feet and went from 240.0 Lbs to 175.8 Lbs that I weighed myself at this morning so I truly know that it works.

  23. Krisztina says:

    I just started IF 16/8 but noticed that I am struggling to eat even the 1500 kcal as I am not hungry. I would need 1800 kcal a day to maintain but just want to eat 1500 to lose some weight. I am afraid I am not eating enough. Any ideas?

  24. Rebecca Moore says:

    Great help, this article!
    New to this. Does it matter what times you eat your calories during the 8-hour window? Better in two meals, or snacking? Does it matter at all?

  25. Jeff Smith says:

    How do I go about getting my recommended protein on an ADF diet? My daily protein target is about 70 grams minimum at my weight of 195 lbs. Therefore in an alternate day eating regimen, I need eat about 140 grams on my eating days. Any recommendations on how to achieve this amount on a WFPB diet? Thank you.

  26. I’ve been fasting and eating healthier during my feeding window for over three months now.

    I have more energy, my workouts are better, and I’ve lost fat (total of roughly 20 lbs to date)

    It’s not for everyone as you have to train your body to eat in smaller windows but it’s worth a shot if you have talked to your doctor.

    Download the zero app. On iPhone it’s much better than android. This helps you track fasting!

  27. Good article. I do not agree that a vegan diet is the ‘creme de la creme’. In fact it is rated as the 16th best diet (of the top 100 diets) by scientists at the longevity institute in California. The best diet for human health and longevity is the Mediterranean diet that is mostly plant based but includes small portions of fish and eggs per week. If you Google that you will see that is fairly consistently accepted. This is the diet I follow and I am ripped muscle and super healthy at almost 50. Everyone guesses my age at 35. Sorry Vegans 🙁

    • In support of that, the longest living people in the world come from an island off the coast of Japan and the Sardinians off the coast of Italy. Their diets include fish

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