How to Fast Intermittently: Different Options

No breakfast, ever again? Impossible. I could never function properly during the day without a decent breakfast!

I can’t tell you how many times I have heard these three statements since I started intermittent fasting. Most people feel this way about breakfast because this is what we have been taught for decades. In direct opposition to this conviction, there is a fast-growing number of people who function perfectly well and often do some of their best work on an empty stomach. Those same people think nothing of running 5, 10, 15 even 21 km without any breakfast whatsoever — and clock better times than when they eat before their run. Same goes for weight-lifting workouts, cycling, swimming, surfing, rock-climbing, hiking and so on and so forth.

In the Facebook groups I have joined (see ‘Intermittent Fasting Works’), people talk at length about how much clearer their minds are and how much more productive they are since they have started intermittent fasting. They discuss exercising on empty stomachs, and many prefer it to exercising while eating three meals a day. I have found this to be true for me too. I run 5 days out of 7 on an empty stomach, for 30 minutes: some long, slow runs but also at least two HIIT (high-intensity interval training) sessions per week. I usually run first thing in the morning and do not eat anything until one o’clock, and I suffer no adverse effects.

The good news is, you do not HAVE to give up breakfast.

Admittedly, I had no problems giving up breakfast. I have never been a big breakfast eater, not even while I was still working ten- to twelve-hour days as a medical doctor. A cup of coffee was all I needed until I started feeling hungry at lunchtime. Now that I write, that cup (or cups!) of coffee has become a writing aid.

Luckily, intermittent fasting is not a one-size-fits-all solution.

There are many ways to fast intermittently. There is the 5:2, the ADF, the 16/8, the 18/6, the OMAD, the eat-stop-eat method, and the extended fast. I started with the 5:2, as described in Dr Michael Mosley’s book, The Fast Diet. This means that you eat normally for 5 days of the week and fast for 2 days of the week. The two fasting days do not have to follow one another and are not total fasts. You are allowed 800 calories on your fasting days, and you can eat whatever you want, although the author does suggest that you eat as healthily as possible. I have two friends who have been doing this for years. It suits them; they have no interest in trying any of the other methods.

I did not last long on 5:2.

I discovered that I do better on a consistent every-day-more-or-less-the-same sort of plan. You will shortly find out why I said, “more-or-less.” I switched over first to 14/10 (fasting for 14 hours and eating two meals in the remaining 10 hours) and then to 16/8. 16/8 worked well for me. I would start a fast at 21h00 in the evening and stop it at 13h00 the next day. During the next 8 hours, because I was getting ready for a big operation, I would concentrate on eating healthily and getting all the nutrients I needed to be in top condition by the time I was going to have the surgery. I wouldn’t say it was effortless, that would be a lie. It took quite a lot of getting used too, especially not eating after 21h00. I used to love a piece of chocolate (or 2 or 3 or a whole bar) after dinner, and a cup of hot chocolate did not come amiss just before bedtime either. I later changed to 18/6 and have been settled on this way of eating for 9 months now. I did try ADF (alternate day fasting, where you fast every second day) but this did not work for me for the same reasons 5:2 does not work. I also tried OMAD (or one-meal-a-day, which is usually a 20/4 fast: you eat one large meal during the 4 non-fasting hours) but this made me binge, so I soon stopped that. I did a couple of extended fasts, though rarely longer than 24 hours. I start my 24-hour fasts after dinner at 19h00 in the evening and break my fast at 19h00 the next day, with dinner (eat-stop-eat method.) Some people do much longer fasts: 2, 3 5, 7 and even up to 30 days — yes, apparently it can be done! But I am not yet convinced of the value of these ultra-fasts.

I said “more or less,” because intermittent fasting allows for quite some flexibility.

If I go out to dinner, I thoroughly enjoy everything on offer. I note the time the meal is finished and then add 18 hours to that. If the meal stopped at 22h, I fast until 16h the next day. Sometimes I manage that, other times I do not, and I don’t beat myself up about it. Life’s too short.

I said earlier that you do not have to give up breakfast. Die-hard I-won’t-survive-without-breakfast people can also fast intermittently without losing out on any of the benefits. You may decide to start fasting at 18h, on a 16/8, and stop your fast at 10h the next morning, allowing for a late breakfast, lunch and early dinner. You can move the 8 hours during which you eat to any part of the day, as long as you fast for the other 16 hours.

Intermittent fasting does not mean intermittent starving.

You still have to make sure that your body gets the nutrients it needs during the hours that you eat. The bad news is that, especially if you want to lose weight, you cannot binge on whatever you have in the fridge during those hours. More about that in my next article.

Making such a huge change in your eating habits can be challenging. I have created the 5-Day Introduction to Intermittent Fasting retreat as well as a Coping with Change Cheat Sheet and Checklist to make it easier.


Disclaimer: While intermittent fasting has many potential and some evidence-based research-backed benefits, it remains a controversial way of eating. Before you make any changes in your eating habits, discuss your plans with your doctor, especially if you are on medication. People who should NOT fast include those who are underweight, have eating disorders like anorexia, are pregnant or breastfeeding, and people under the age of 18. The content of this story is for informational purposes only and are not intended to serve as a substitute for the consultation, diagnosis and medical treatment by a qualified physician or healthcare provider.


Dr Margaretha Montagu is a recycled medical doctor, a rogue writer of self-help books and passable presenter of personal empowerment workshops. She lives on a small farm in the not-always sun-blessed south of France with five opinionated horses and all her books are horse-inspired, subtly French- flavoured and hopefully life-enriching. She also shares her somewhat-outlandish ideas with you on her blogTwitter and LinkedIn.