In Tim Ferriss’ new book Tools of Titans he puts forward a method to optimize the process of fasting. In his typical 80/20 approach his formula aims to get the most benefits, in the least amount of time.
His recommended fast is conducted in a 3 day period, spanning Thursday evening to Sunday evening.
3-Day Fast Overview
- Stop eating Thursday night
- Friday morning go for a long walk to accelerate your transition into ketosis
- Friday and Saturday stay fasted, and consume moderate amounts of exogenous ketones and MCT oil (as needed), to give you a boost while you’re keto adapting.
- Sunday evening you break the fast.
Here’s the process in more detail if you don’t have Tools of Titans to hand:
- Eat a low carbohydrate dinner around 6pm. Make that the last meal of the day. Go to bed as normal.
- Drink some caffeine if needed, then get out the door and walk within 30 minutes of waking.
- Bring at least 1 litre of water, with some added salt (to prevent headaches/cramping), and sip as you walk.
- Walk for 3-4 hours(!). Filling up/buying more water as needed.
- Arrange phone calls for this time, to make the time productive.
- The idea behind the walk is that you use up your glycogen stores, forcing your body to move quicker into deep ketosis. The quicker you get into ketosis, the less time you spend feeling sub-optimal, and the less potential muscle wastage.
Friday Day (post walk)
- Consume exogenous ketones or MCT oil 2-3 times throughout the day, where necessary.
- Tim primarily uses KetoCaNa & KetoForce as exogenous ketone sources. The KetoCaNa is the weaker of the two, but is the most palatable. KetoForce would have a greater impact on your blood ketone level (beta-hydroxybutyrate). KetoForce is an alkaline liquid, that you can add to water to drink. To balance out the alkalinity you can add some lemon juice.
- The intention with these ketone sources is to provide your body and brain energy until your ketone levels elevate naturally. At which point the feelings of hunger will reduce, and you will feel like you have more energy.
- Upon waking, test blood ketones. You are aiming to be at 0.7mmol or greater. Ideally use a ketone blood testing meter like the Precision Xtra. Urine testing strips (cheaper option) are not accurate enough.
- If you’re at 0.7mmol, great, proceed normally with your day.
- If you’re under, consider going for another extended walk, and then re-test.
Saturday & Sunday Day
- Add further exogenous ketones or MCT oil if you need a boost. Once you are deep into ketosis they can be omitted.
- Incorporate some sodium in your water throughout the day. This can either be in the form of himalayan sea salt added to water, or via a specially formulated solution such as SaltStick electrolyte replacement pills.
- You can break your fast. Tim suggests for longer fasts, some care is needed on the re-feed. But for this 3 day fast, it doesn’t matter as much. Eat what you find to eat.
Tim Ferriss now aims to do this 3 day fast process once per month. With a 5-7 day fast once every 3 months.
If you’d like to talk more about fasting, or share your experience doing this one, join this open Facebook group on the subject.
Another thing to mention, if you plan to go down the route of testing your ketones, is that for the optimal health benefits it’s likely you want to be in what’s called ‘nutritional ketosis’. This is where you have a ratio of 1:1 or lower of blood glucose to blood ketones. Why is this relevant? Because its totally possible to have a high level of blood ketones, but ALSO a relatively high level of blood glucose. So ideally you want to get that blood glucose reading down. I’ve written some more words on that here.
If you enjoy Tim Ferriss’ work, you may also enjoy this post on Rhonda Patrick’s recommended supplements.