We’re wrapping up our two-part series this week by discussing some of the most popular fasting protocols. Specifically, I want to look at their effectiveness, or lack thereof, for weight management (which seems to be the most popular use case). Now that you have a good handle on what is actually going on inside the body, you’re ready to take a critical look at these diet types.
Time Restricted Feeding (TRF)
TRF is more commonly referred to as intermittent fasting. TRF has multiple health and wellness benefits IF it helps the individual align their circadian rhythms.
To briefly summarize the relation between circadian rhythms and nutrition – Humans are diurnal creatures (as opposed to nocturnal). This means our physiologies are primed to do stuff when the sun is out, and primed to not do stuff when the sun goes down. If you force your body to do stuff when it shouldn’t, like eating at 2am, then you have two competing signals occurring at the exact same time.
It’s like pressing on the gas and brakes at the same time. It’s inefficient, won’t work, and eventually causes major issues.
This circadian misalignment is the mechanism through which nightshift workers have been shown to be at increased risk for literally every medical condition we’ve looked at. Admittedly, not everyone is a nightshift worker. However, there is no ‘safety’ threshold. Any continued misalignment will lead to increased risk. The degree of your misalignment determines the degree of your increased risk, with a 12-hour misalignment being the worst-case scenario.
All TRF protocols I’ve seen tell users to eat during the daylight (which is great). You won’t find a TRF protocol with a feeding window from 10pm to 6am. And if you go from misaligned to aligned, you will see amazing benefits.
With all that being said, weight loss does not occur with any TRF variant unless it also restricts your caloric intake. Presumably, with shorter feeding windows, you will have less opportunities to eat and will naturally restrict intake. Many people have success on TRF protocols and do lose weight. I’ve recommended TRF variants to people who struggle with eating too much across a large feeding window and who work well with an imposed structure / hard cutoff times.
Alternate Day Fasting (ADF)
ADF is exactly what it sounds like, a 24-hour fast followed by a 24-hour feeding window.
The diet can be followed as long as the user wants, and is well validated in the scientific literature. There are countless studies supporting use for weight loss.
What you see is that people will eat more than their maintenance needs on their feeding day, but that it is NOT enough to fully compensate for the fast day. For example, maybe you need 2,000 calories per day. On the feeding day, you’ll naturally try to eat more, but you won’t eat 4,000 calories. You’ll maybe eat 2,500-3,500.
Although the protocol produces reliable weight loss, it is somewhat difficult to adhere to. Many people don’t like the idea of having to go a full day without food. An easier variant was created that has people eat a small meal on their fast days for dinner (<500 calories) with only a minimal loss in efficacy.
If the modified ADF protocol still sounds too scary, the 5/2 might be worth considering. It is an easier variant than the ADF protocol. It involves two 24-hour fasts in a week (rather than an average 3.5 days in a week).
To make the 5/2 protocol more manageable, you can again allow a small meal for dinner (<500 calories). I personally like to start here with people who are new to fasting and looking to experiment. Yes, the results are more modest due to the smaller restriction, but it is a nice way to test how your body handles fasting protocols. Fasting is not for everyone!
Monthly 5-Day Fast
A once per month 5-day fast has been shown to produce modest weight loss. Of note, it is the ONLY researched fasting protocol that begins to activate the benefits that come from true extended fasts – things like trimming the inefficient cells and regrowing new cells, anti-cancer effects, etc. (in agreement with our switch in metabolism that occurs over this duration).
A 5-day fast is very daunting and SHOULD NOT BE DONE WITHOUT FIRST CONSULTING A MEDICAL PROFESSIONAL.
An easier variation has been created that uses a fasting ‘mimic’ protocol. You can still eat on the 5 days, but the diet is very particular. Specifically, carbohydrate, protein, and calories are restricted. Users will eat mostly vegetables and healthy sources of fat. It also has been shown to produce weight loss.
Please reach out to me if you’re thinking of actually doing it, so that we can make sure you do it safely.
Thanks for reading this week. There are other types of fasts, but these are the most common ones I’ve been asked about and that have some research behind them. Please shoot me a message with any feedback you may have, or any other types of fasts you’d like me to cover! My email is firstname.lastname@example.org and I’d love to hear from you.
Until next time, take care.