was successfully added to your cart.


with Caryn, the Whole Food Dietitian

I have recently finished my first ever 3-day fast (well 72 hours anyway) and I wanted to give you my reasons for doing it and relay my experiences – in brief. So here goes.

Reasons for doing it:

The science around fasting for a range of health benefits is compelling, and includes benefits for weight loss, blood sugar control, immunity, anti-ageing and more. For me it was mainly about four aspects:

  1. Mental clarity that comes with being in deep nutritional ketosis.
  2. Benefits of “Apoptosis” and “Autophagy”, essentially cell death and cell clean-up and rejuvenation of cells that have passed both their best before and use-by dates. I believe this is something I can do a couple of times a year along with the other things I do more regularly (eat well, sleep well, live well) as well as shorter fasts to ward off degeneration of the brain and any cell-waywardness.
  3. Longevity and anti-ageing properties. There are only a few things we can actively do for anti-ageing, so I’m taking this one.
  4. Simply, just to experience it. The value in exploring your relationship with food (even if you think you have an ok one) is a total eye-opener and is very worthwhile – if you are a reflective person that is.

My experiences and musings for those who care…(written in the present tense – purely for dramatisation ;))

Day 1.

This is easy (as I’ve done it before). I actually started off doing a planned 24-hour fast. But now I’m thinking well, I’m 1/3 of the way there, I might as well. I really want to do a 3-day, but I don’t actually want to do it. The environment is not right, I’m working at home, by the kitchen. Oh stop making excuses and just do it. I can’t stop thinking about what I’m contemplating to do. Just do it! Ok, I’m doing it!

Night 1:

Husband Mark makes an omelette for dinner, no problem for me, I feel fine, but dreading tomorrow as I believe day 2 is hard. Still obsessing that I’m actually doing this. Keep thinking about the next day and the next day.


Not a great sleep as I woke up a few times stressing about what I was doing.

Day 1 Blood ketones: 
9am: 0.1 (not in ketosis)
3pm: 0.4 (on the cusp of ketosis)
9pm: 1.1 (in ketosis)

Day 2:

Working like a trojan. I’m totally coping, don’t listen to what they tell you, everyone is different. It’s now 2pm, and oh no, here comes a hunger wave. 10 minutes later: It’s over, ok not so bad. Brisk walk with dog – Pepper, I feel good, great even.

Night 2:

Mark cooks dinner. Lamb, my favourite. Hmmm, now it feels hard. I see a chocolate tasting on TV, oh dear, now my mouth is watering. Then Mark eats chocolate. Mini-torture. Ok, just move to another room temporarily (out of sight, out of mind). It works. No problem. Come back for cuppa tea and some Netflix. All back under control.


Better sleep as I stopped stressing about it.

Day 2 ketones: 
3pm: 1.2 (in ketosis)
9pm: 2.1 (deep in ketosis)
(only two readings as I had to ration ketone strips, as I only had a few with me).

Day 3:

Wake up. Feel tired and have headache, maybe I should stop. No, just have more salt and fluid. What do you know? Headache is gone, and by 10am I feel great.
All day 3: No hunger, what..so..ever, just feeling empty. (Empty- not hungry, an interesting feeling). Again working well, keeping busy.

Day 3 at 7pm

End of 72 hours – I could’ve continued as there was no hunger at all, but social activity arrived and I was only psyched up for 72 hours, so that’s where it ended.

Day 3 ketones: 
8am: 2.4 (deep in ketosis)
7pm ketones: 4.1 (deep in ketosis)
Followed by a delicious, super-nutritious meal!

Parting thoughts:

  • Did I get more clarity? I might have, but I’m not totally convinced of it – just being honest here, but that might be because I generally eat LCHF and feel energised when I work a lot of the time, because I love my work, it energises me. I’m also never tired during the day, despite getting up most days at 5:35am. I worked well over the last 3 days, for sure, but then again, I always do when I work from home and I get no disturbances. So maybe…maybe not.
  • Did I reflect on how often I usually eat and why? I sure did, a fascinating, introspective experience, even for me who doesn’t have any real food issues (apart from knowingly eating too much chocolate). From this perspective, it was a profound learning experience.
  • Was it hard? On the whole, it was tough, but a lot easier than I expected.

Bottom line: It’s really interesting what you can do when you put your mind to it. Apart from talking, reading and writing about food every day, I really love eating food and going without it for 3 days was a real challenge for me, not physically, but mentally. I wasn’t hungry at all, just “psychologically hungry”, an incredibly interesting concept.

Would I do it again? yes, but not for a couple of months. Back to the short stuff, where it’s easy, you still get some great benefits and it’s not so taxing on the psyche.

The best piece of advice I can give when doing longer fasts? Just don’t overthink it!

Leave a Reply

Join our mailing list to receive the latest news, sneak previews and special offers from What The Fat?

You will recieve The Skinny as a sign up bonus - a 4-page practical guide to eating the Low Carb Healthy Fat (LCHF) way.

Thanks, you are subscribed!