Learn how to intermittent fast with this easy guide for beginners, including intermittent fasting benefits, types of fasting schedules, how intermittent fasting on keto works, and answers to common questions.
By Maya KrampfAffiliate links for products I use help keep my content free. Ads are not my endorsements. See my disclosure and how I develop recipes in my kitchen. For an ad-free experience and more perks, try Wholesome Yum Plus.
Intermittent fasting is one of the most popular dieting trends in the last several years, including intermittent fasting on keto. However, much like the keto diet itself, intermittent fasting for beginners can be difficult to understand and carry out correctly. This guide will tell you everything you need to know: how to intermittent fast, intermittent fasting benefits, and how it aligns with a low carb lifestyle so you can enjoy everything this way of eating has to offer.
Intermittent fasting is an intentional approach to eating that cycles between periods of eating and periods of fasting (aka, not eating). It doesn’t tell you what to eat, so it’s not a diet — it influences when you eat instead. That means you can not only practice intermittent fasting on keto, but on any kind of eating plan.
Although humans have fasted for thousands of years out of necessity (in times of food scarcity) or for religious reasons, people now use intermittent fasting for weight loss and other health benefits.
Is it practical to do intermittent fasting for weight loss? Absolutely. Studies show that intermittent fasting can naturally restrict calorie intake and appetite, which can lead to weight loss [*].
However, intermittent fasting also works on a hormonal level by releasing more norepinephrine, a fat burning hormone. This hormonal shift can increase your resting metabolic rate [*, *], which means you can burn more calories, more efficiently — even in a resting state.
By restricting calories and increasing the rate at which you burn calories, an intermittent fasting schedule can lead to weight loss.
Although an intermittent fasting plan works for weight loss, it also kickstarts other biological processes depending on how long you do it:
Fasting, especially intermittent fasting on keto, allows you to gain an array of key health benefits:
Fasting lowers insulin levels and triggers fat burning mechanisms in the body [*]. After a short period of hunger while your body adjusts to fasting, this approach also stabilizes blood glucose levels [*].
Fasting is linked with better markers for heart health, including lowered cholesterol and blood pressure [*].
Fasting “turns on” a cleanup process in the body called autophagy, which protects against oxidative stress and can help keep your cells younger [*].
Through autophagy, fasting reduces inflammation [*], defends against Alzheimer’s disease in the body [*], and may even assist with killing cancer cells [*].
Studies show that intermittent fasting targets and burns more visceral fat, the tough-to-lose fat around your midsection [*].
Fasting helps you think clearly by boosting brain-derived neurotrophic factor (BDNF), a protein linked with learning and better mood [*, *].
Intermittent fasting cuts down on decision fatigue over what to eat, time spent on cooking, and food cleanup. When you don’t stop to eat as much, you can spend more time on other things.
Intermittent fasting on keto is easy, as long as you follow a few simple guidelines.
Wondering how to do intermittent fasting for the first time? Start with a smaller fasting window, such as 12 hours, before exploring longer fasting times.
With an early dinnertime or late breakfast (and no snacking), you can easily achieve a 12-hour fast. Then, you can experiment with the fasting schedules below.
There are no intermittent fasting times that work for everybody – experiment to find the best one for you! Here are some of the most popular ones, any of which will work as an intermittent fasting keto schedule:
16:8 is one of the most popular ways to practice intermittent fasting for beginners. This keto beginner meal plan provides a way to practice keto and intermittent fasting with easy low carb meals for your eating window — just omit the breakfast to practice fasting.
Intermittent fasting for beginners comes with a lot of questions. Here are the most common ones:
Yes, you can and should drink water! You can also enjoy any zero-calorie beverages.
Intermittent fasting coffee is fine to drink, but make it plain. (Same with tea!) Avoid adding anything to it that will add calories, and thus break your fast.
Cream contains enough calories to potentially break a fast and lose out on the benefits, so it is not recommended.
The general rule is that anything with calories breaks a fast. The main exceptions are supplements, electrolytes, and medications:
During your fasting window, you shouldn’t eat anything. 😉 During your eating window, enjoy nutrient-dense keto foods like healthy proteins, vegetables, and fats.
Avoid breaking your fast with processed foods, carb-heavy meals, and dirty keto foods, as these can hinder the health benefits of fasting in the first place.
Research shows that people can fast successfully with mild, minimal side effects. Dangerous intermittent fasting side effects are more likely to occur when people undergo long-term fasts, continue fasting despite feeling serious side effects, or re-feed with unhealthy foods [*].
Intermittent fasting side effects are minor for most people. You may feel mild hunger or weakness, and these are normal. Generally, electrolytes can minimize these side effects so the transition into fasting is not so harsh.
For the average person with no health conditions, fasting is generally safe and aligns with human biological processes for waking, metabolizing food, and repairing cells [*].
However, you should check with your healthcare provider before fasting. Fasting is also not recommended for children, pregnant or breastfeeding women, or anyone with a medical condition a history of disordered eating.
How long is intermittent fasting sustainable? When it comes to intermittent fasting for beginners, 24 hours or fewer is a safe limit.
Those more experienced with fasting may go 48-72 hours, or even longer — however, you’ll have to experiment and work up to a long fasting window, and stop if it doesn’t feel right or keeps you from doing daily tasks.
You can incorporate some form of fasting into your schedule every day, as long as you stay healthy and nourished with the right foods during your eating windows.
This way of eating can align with keto, and some research shows that it can help you achieve better fasting results [*].
Rather than thinking of these approaches as “intermittent fasting vs keto,” they can work together to ensure you don’t feel hungry since you’ll enjoy healthy and satisfying fats during your eating widow.
As long as you are generally healthy and have no underlying medical conditions, learning how to intermittent fast can help you gain all the amazing benefits of this dietary approach. Try intermittent fasting on keto to stay nourished with healthy fats, and feel less hungry during your fasting window.
Published Jan 25, 2021 Filed Under: Keto ArticlesKeto Recipes Keto
I’m a recipe developer and USA Today best-selling cookbook author, and I’ve been creating easy, healthy recipes using whole, real food for more than a decade — all with 10 ingredients or less! Learn about how I develop recipes here.
I love vegetables, a perfectly cooked filet mignon, and a good cup of coffee. I’m passionate about healthy eating without refined sugar, so I created Wholesome Yum Foods, a line of zero sugar ingredients for cooking and baking.
Very helpful, as I have been on Keto for a while now, and I have diabetes. I feel good doing a 12 – 16 hr fast. I have noticed a drop in my blood sugar count, as well my BP has dropped to where I think I should be able to drop one of my three pills. Thanks so much for confirming I doing a good thing.
Pamela Walsh 0 Jul 4, 2023 ReplyI’ve been doing the Keto diet–it’s a lifestyle now for me—for about 1-1/2 years. I’ve been in maintenance mode at my new weight for a while now but I’m now ready to try and loose another 40 pounds or so and do it as quickly as possible. I’m thinking that fasting in addition to keto might get me there. Could I drink a cup of bone broth–less than 1g of carbs–along with water during my 16 hrs of fasting? I have read that bone broth has a lot of good things in it but I don’t want to drink it during fasting if it’s going to be counterproductive.
Wholesome Yum D 0 Jul 5, 2023 Reply Hi Pamela, You want to keep your calorie in take under 50 so you don’t break your fast. Dena Ellis 0 May 21, 2023 ReplyI have always been confused about how to do intermittent fasting I’ve been on keto 5 years and now I figure I know what I’m supposed to be doing thank you for all of this.
Tom Casadonte 0 Mar 4, 2023 ReplyHow many calories should I consume during my feeding window? I plan on eating breakfast and lunch and skipping dinner. My breakfast is usually 450 cals and lunch about 400-500 cals. If I am skipping dinner I would think I would need to amp those up to 750 each at least. Also, I am near my weight goal so for weight maintenance I might need to go even higher. Your thoughts?
Wholesome Yum D 0 Mar 6, 2023 ReplyHi Tom, I recommend calculating how many calories you need using a macro calculator. You would want to consume that amount of calories in your eating window. As far as maintenance you will want to redo your macros because they will change when you switch from weight loss to maintenance.
Pauline Duren 0 Jan 15, 2023 ReplyHi , I am doing a daily 18-6 fasting with a keto diet. During fasting I have keto electrolyte black tea or coffee and water. Then I have a keto meal at 12.30 and another at 6.30pm then begin fasting again …
Can I snack between the two meals ??
Is it okay to consume vital proteins collagen coffee creamer while fasting? It says on the website that it is okay but im sure any website trying to sell something would advise so. Let me know! Thanks!
Maya | Wholesome Yum 0 Nov 20, 2022 Reply Hi Becca, Anything with calories would break a fast, so collagen peptides would as well. cherif 0 Sep 5, 2022 Reply Roberta Phucas 0 Apr 17, 2022 ReplyCan I take my Supplements that are in the form of gummy’s instead of pills while on the keto diet and when I am intermediate fasting? I have a hard time swallowing a lot of capsules and large pills, and I have a lot of supplements that I take. Most are all gummy supplements and have between 2 to 4 sugars
Wholesome Yum D 0 Apr 18, 2022 ReplyHi Roberta, That is a personal preference, you will have to check the nutrition facts to see if they fit into your macros.
Anne 0 Mar 23, 2022 ReplyAccording to the Macro Calculator, I’m to get 1769 calories per day and it breaks it down for me. I’m doing 16:8. Two questions. 1. Is it ok if I end up eating fewer calories than 1769?
2. When do I get to eat my Keto cheesecake? Is that considered a meal or what?
Hi Anne, The macro calculator is just a guide, it is ok if you don’t always reach the set calories. You can eat anytime in that 8 hour window, here is more info on intermittent fasting.
June McCormick 0 Mar 8, 2022 Reply Do you get cheat days on intermittent fasting? Wholesome Yum D 0 Mar 8, 2022 Reply Hi June, That would be a personal decision if you want to go off plan while you intermittent fast. Elizabeth Enyima Nyarkoh 0 Mar 7, 2022 Reply This information is very useful.When I was young I belonged to religious group and fasted often on water for 24 hrs to one week at a time. We began and ended fasts very poorly. My metabolism never recovered and as a result if I am too calorically restricted my metabolism just slows down in reaction. Will intermittent fasting, 5:2 be appropriate for me?
Wholesome Yum M 0 May 7, 2021 ReplyHi Debbie, Please keep in mind that fasting is not a requirement of the keto diet. It is a popular addition, but by no means is it necessary. That said, you may want to try a daily fast (or eating window) instead of fasting for days at a time. 16:8 is a popular starting point. It is 16 hours of fasting followed by an 8-hour eating window. I hope this helps!
Glenn 0 Feb 26, 2021 ReplyHow many calories does it take to break an intermittent fast? For example, at around the 14 hour mark, I have typically drank some BHP Ketone powder mixed with water that has 50 cal. Is that too much?
Love your site!!
Glenn
Hi Glenn, The amount will vary depending on which keto expert you talk to! I believe if you are keeping the amount to 50 calories or less you should be fine.
