When should I schedule my fast?

There are many considerations to think about when planning or scheduling a multi-day fast. Are you experienced at fasting? Do you have upcoming dinner plans? Do you have any important meetings or a big day at work? Are you traveling? Do you have time to do the long walk in the morning? Are you hosting guests?

You’ll need to experiment a bit to see what works for you at first. “When” will matter less over time. 

The more you do it, the easier it gets. Once you get advanced and your confidence improves, you can pretty much do a fast on demand, no matter the situation. Have a busy work week with intense meetings? No problem, you can power through with more focus than usual. Have a packed social calendar with meals with friends? No worries, you can still sit with your friends and drink tea or sparkling water, and not be tempted in any way. Have a few long days of travel with less-than-ideal food options? Not an issue, just use it as an opportunity to get some fasting in and don’t worry about procuring food.

How Often to Fast

It is a good idea to space out your fasts in order to give your body an opportunity to recover (regain strength, normalize hormone levels, regain some weight etc). For 3+-day fasts, I recommend no more than once per month. If you have a ton of extra weight/fat to lose or a pressing short term weight loss goal, you could experiment with fasting as frequently as every 2 weeks (for a couple months), but I would be extra conscious about maintaining muscle mass in this situation.

Time of week

There are two general schools of thought – minimizing social disruptions and minimizing work disruptions. To minimize social disruptions, fast early in the week instead of the weekend. Monday is a good day for a last meal (and start the fast). To minimize work disruptions, have your last meal on Thursday night and end Sunday.

If you are doing a 3-day fast starting on (last meal on)…

• Sunday, you finish Wednesday. If you have a quiet Sunday planned, this can be a decent day to start. Y However, oftentimes there are family meals/activities, you are coming back from a trip or have been drinking the night before. It is more challenging staying disciplined on a Sunday
• [Ideal if you want to minimize social disruptions] Monday, you finish Thursday. The weekend is over and you can start the week fresh and with discipline. It is a quieter time of the week so you can focus on you, and still be able to resume all normal activity for the upcoming weekend. It is easier to get into a fast, if you have eaten clean that day. That means low carb, no alcohol, and finishing your last meal earlier in the day. It is easier for me to do that on a Monday.
• Tuesday, you finish Friday. Decent timing, assuming you don’t have plans Thursday night, and you break your fast earlier in the day to be able to have a normal meal at dinner time Friday.
• Wednesday, you finish Saturday. Not ideal. You are out of commission on Friday and part of Saturday.
• [Ideal if you want to minimize work disruptions] Thursday, you finish Sunday. Not ideal if you have social obligations. You miss the weekend. However, it is ideal if you want to minimize work disruptions. This can be a good choice if you are new to fasting and don’t know how your body will react and don’t want to risk potentially ruining a few days at work.
• Friday, you finish Monday. Not ideal because you lost out on the weekend.
• Saturday, you finish Tuesday. You will probably have time in the morning to go on your 2-4 hour walkabout.

Timing of last meal

An early dinner, starting at 5 PM, ending at 6 PM is usually the easiest for Day 0 (day of last meal). It is late enough that you can make it to bedtime without getting hungry, but also early enough that you get a few bonus hours of fasting for free (i.e. time in a fasted state that doesn’t really feel like fasting because you are sleeping).

Social obligations

Think about what social plans you have for the fasting period. Are you hosting people at your house where they expect to be fed? Do you have dinner plans? Do you have tickets to an event where you would normally want to eat/drink?

In general it is easier to fast when you do not have social obligations that involve food. Once you become more experienced with fasting and also gain more confidence talking about fasting, you will be able to resist temptation during social obligations and have more flexibility here. 

Work demands

Two schools of thought here. Do you fast during an easy week because you don’t want to risk low performance? Or do you fast during a hard week, because work will distract you from fasting and you’ll gain extra time by not worrying about eating.

If you have a particularly grueling day/week at work or have important meetings/tasks where you absolutely need to perform, you should perhaps schedule your fast at a different time. Especially if this is one of your first fasts and you don’t know how your body will react. Many people report decreased ability to focus especially in the beginning of the fast before your fat adapted or if you are new to fasting. Sometimes, you may just zone out in front of the computer and not know where the time went. If you don’t want to take that risk, choose a different time.

On the other hand, on Day 2+ fast (when you are fully in ketosis), or if you are a seasoned faster, you may want to fast during high work demands because often you will be in a slightly elevated/energized mental state and don’t have to waste time making, eating, and cleaning up after food.

I started in the first camp, but gradually transitioned in the second camp.

Travel 

For beginners avoid fasting during travel like a long plane ride. You don’t fully know how your body is going to react (whether you feel lightheaded, maybe nauseous). You want to make sure you have your wits about you.

For pros, fasting over travel days can be great. Airport and airplane food/snacks are not the greatest anyway. You can’t really get in any hard exercise that you may normally want food to recover from. Why not use the extra time to get some fasting in?

Coming back from vacation. After coming back from vacation, I am sometimes tempted to detox with a fast ASAP. However, I usually wait a few days so I can get my nutrition, sleep, and exercise in a good place before starting the fast.

Sleep over previous days 

If sleep has been particularly bad the past few days, perhaps hold off. Sleep on a multi-day fast usually takes a hit, so you don’t want to come into it with low sleep.

If sleep has been decent the past 2+ nights, proceed.

Exercise over previous days 

I am very cognizant about trying to maintain strength and reduce muscle loss when doing a fast. If I have been lifting regularly and either maintaining or gaining strength. I will lift on the morning of Day 0, and proceed with the fast.

If I have not been lifting regularly, whether it be from traveling or something else, I would try to get 3-4 days of lifting in before starting to fast. Preferably I would like to see strength increase, but I like to at least stop the decline of strength from the prior weeks of inactivity.

Activities planned 

There are two approaches here. (1) Schedule the fast when you have a low amount of activities planned, so you can focus on the fast, and don’t risk ruining your activities. (2) Schedule the fast when you have a lot of activities planned as a distraction to food, so that you are not just sitting around all day dreaming about food.

Eating over previous days 

If you have been eating like shit the past 3+ days (low vegetables, high carbs), I would focus on getting a few days of solid nutrition in as well as a low/no carb day on Day 0 before starting the fast.

Alcohol over previous days

It’s not ideal to start a fast if you have been drinking the day of your last meal (and preferably the night before).

Fasting when your significant other or family is out of town

This is a nice little hack. If you are home alone and you don’t have much else going on, then why bother with cooking and clean-up. Use the extra time to focus on your own projects and get your fasting done at the same time.