Rx Fasting

"Fasting is the greatest remedy - the physician within."

Philippus Paracelsus, one of the
three fathers of Western medicine

Just as there are many diets out there, there are also numerous ways to fast.

See our page on Fasting.

We all fast every day – from the time we go to bed and get up and taste our

first food of the day. We need good sleep to aid the body, and when we fast,

it’s like we stop scratching our itches and allow the body to begin healing.


The benefits of water fasting

Fasting brings many benefits, and the longer you can fast, the greater the benefits.


For some regular short fasts (lasting no more than 36 hours and not a true fast as the body never fully enters into ketone metabolism where it burns body fat exclusively for energy) is as much as they can make. But, nonetheless, 36 hours of fasting still brings benefits provided you don’t pig out as soon as you resume eating but instead plan to re-introduce light food!


So, here’s how you can expect to benefit. A short fast….

  • Energises

  • Improves appetite control

  • Improves fat burning

  • Improves insulin sensitivity (and decreases insulin levels)

  • Improves cardiovascular function

  • Improves memory and cognitive function

  • Lowers body fat

  • Reduces blood lipids (ie LDL (the bad) cholesterol)

  • Reduces blood pressure

  • Reduces cancer risk

  • Reduces chronic inflammation 

  • Reduces oxidative stress

  • Reduces triglycerides (the main form of fat in the body, the end product of digesting and breaking down bulky fats plus any extra food we eat that's not used for energy right away - carbohydrates, fat, or protein

  • Ups the feel-good factor and clarity of mind


A 36 - 48 hours fast

I’ve tried numerous fasts in the past but usually most fell by the wayside; I have a very irregular, oft changing time schedule. So sometimes I buy in foods to fit around the fasting schedule only to find that the schedule changes drastically, I find myself away from home, and fasting fastly fades! As do the withering vegetables in the fridge.

So I have taken to a regular 36 – 48 hour water fast in which I drink only water – I avoid fruit juices as they maintain the hunger, and I avoid calorie counting, the 500 calories for one day, such as in the 5:2 Diet ie five days eating, two days fasting. It’s easier to fast drinking only water. There is nothing to organise, nothing to think about, no cooking (or tidying!) and you stop the fast whenever you are ready after 36 hours.

If you are living with a diabetic diagnosis you may wish to alert your health professionals that you are undertaking fasting. As you fast you will find your insulin levels and glucose counts reduce so you need to be alert to the possibility of hypoglycaemic attacks. Always listen to your body when fasting. Be aware of those shaky, tingly, weak signs the body gives to alert you to falling glucose levels and if necessary, check your blood levels, and take any necessary remedial action eg a glucose tablet, less insulin and so on.

Fasting done well will help you reset real hunger and appetite, uplift your mood and help the body rest.

What do I do?

Be aware            Know your goal. Know from the outset that your intention is not just to fast, but to teach the body to respond to your new ways of eating. For the first 24 hours, you’re not fasting as such but simply delaying your first meal of the day. During this time your body uses its immediate reserves: food taken before you start your fast is still being digested. It might tip over to ketone bodies as an energy source but not 100%.

Be aware             How Are You Feeling?

Until you teach the body and mind that change is serious, you can expect some uncomfortable feelings perhaps hunger, perhaps thoughts that you won’t make it, that you can’t do it – your ego will torment you!

Remind yourself of the main benefits you are seeking by fasting.

Visualise life when the benefits of fasting have kicked in. How does it feel to be more energised, clearer in mind, perhaps slimmer and so on? What do you see and how do you feel? Key into that, visualise it, feel it rather than give attention to any hunger pangs.

Inform yourself of the key milestones over the 36 to 48 hours. If you see it as a two day stretch it may feel like too much. See it as blocks of 12 hours which you can successfully tick off on completion and you up your chances of success.

Be radical            Remember the well-worn phrase – “this too will pass!” Especially what's known as "keto flu'"

Be bold                Go for it. You can do it.


A schedule

This is my schedule – adjust it to suit your circumstances especially if you are a shift worker.

Day One Bedtime

  • I eat a light supper at 7pm.

  • I go to bed by 10pm. This is when the fast really begins being timed.

Day two

  • I rise around 7am, have a glass of water, room temperature, and remind myself of my schedule.

  • At 10am I remind myself I have now completed 12 hours and that in and of itself is beneficial.

  • I visualise my intended future having successfully fasted.

  • I sip water throughout the day. I also may have a cup of coffee, or several cups of green tea. Depends on my taste buds at the time.

  • At 10pm I acknowledge I have completed a 24 hour fast and probably by now, feeling some euphoria, will kick the air in celebration.

  • I now give myself the option of continuing the fast or not. But as it is 10pm, it feels like bed time so usually before giving it much more thought, I go to bed.

Day three

  • I awaken again at 7am to a morning glass of room-temperature water.

  • At 10am I remind myself I have now completed 36 hours.

  • I give myself the choice – to now end the fast and eat or continue through to 10pm – ending the fast at 10 (having done 48 hours) or fasting overnight and breaking the fast at breakfast next day with a light low carbohydrate meal – eg eggs and bacon, some fruit, scrambled egg.

  • Reminder, at the 10pm mark, listen to your body.

  • If you waken next morning be guided by your body as to whether it NEEDS to eat or you can continue to fast.

  • I sip water throughout the day. I also may have a cup of coffee, or several cups of green tea.


NB Diabetics – throughout keep monitoring your glucose counts and adjust your medication / insulin accordingly. I have a metre which shows how many units of insulin I need per meal and has an option for “no meal.” Above all, involve your main medical person.

If you are at all concerned, listen to your body and if necessary, decide to break the fast. But avoid the ego's temptation to create panic in your thinking.



People who normally sleep well tend to sleep less during a fast and those who have sleep problems tend to sleep better.

If you wake up in the middle of the night and are genuinely hungry, then break the fast , with some fruit or if you are diabetic, perhaps a piece of protein cheese or cooked ham. Then go back to bed.

After 48 hours, you may feel you could continue your fast but take note of what you plan to do in the next 12 hour period. If you are a manual worker doing heavy work or in a stress-filled profession eg the NHS consider that whether you feel hungry or not, you must refuel to give you energy so break the fast.

The longer the fast, the weaker your digestion so reintroducing food by eating light, modest meals becomes critical.

Avoid a heavy normal meal.

Perhaps it will be sufficient to have a piece of fruit, poached salmon, small salad, boiled or scrambled eggs. Your energy will soon return.

By now you are perhaps listening to your body in a different way.

Continue with your day but listen to your body. It may start telling you it prefers the light, low carbohydrate way of eating, of having “fasts!” You may be hungrier than usual or not. Just listen, follow your hunger and don’t question it. Try to eat as healthy as you can, and hopefully healthier than you did before the fast.

Reminder             A few people cannot fast for even up to 24 hours. People with diabetes can fall into that category so always consult your health professional, listen to their advice, and then listen to your body. As someone with a diagnosis of T2D, I have worked my way up to doing a 36 hour fast with no problems; I was just very strict on monitoring my glucose levels and adjusting my medication.



The Complete Guide to Fasting - Jason Fung


Dr Josh Axe

Diet Doctor

A water fast

Simple &


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