My three-day fasting mimicking diet experiment

Fasting for improved health and body composition is all the rage these days — and while I’m open to its benefits, I’m an eater. I like to eat. It’s one of the biggest joys of my life, and I’m not willing to give it up just so I might live a few years longer (what kind of life is it if I’m barely eating anyway?) So, when I read about Dr. Anthony Gustin’s keto version of Dr. Valter Longo’s fasting mimicking diet, I thought it would be a perfect experiment for me to see if it helps as a temporary hunger reset.

Generally, I follow a lower-carb-than-standard-american-diet, mostly paleo plan, centered around good quality meat, veggies, and healthy fats. Most of my meals consist of eggs, avocado, nuts, salad, chicken, fish, and beef, and vegetables like Brussel’s sprouts, cauliflower, salad greens, and sweet potato, all liberally doused in coconut oil, olive oil, or ghee. I also throw in oatmeal and rice as per my desires and workout intensity. This works very well for me for overall health, athletic performance, and digestive health, but because I’m a big eater in a relatively small body (and I love my sweets) I can sometimes find myself veering into unnecessarily large portions and higher sugar choices if my schedule changes, or I’m stressed, or I’m going out to eat, etc. I find it hard to snap out of the cycle once I’ve begun it, so I figure that a few-day reset with less calories, zero carbs and sugar, and less worrying about food in general might be a good plan of attack.

Fasting in a nutshell: Intermittent fasting, which can include daily time-restrict eating windows (say, only eating between noon and 6 pm every day and fasting the other 18 hours) up to 24 hour and even seven-day fasts or longer, can have benefits including improving insulin sensitivity and fat loss, and even greater effects for folks dealing with certain health conditions. That’s beyond the scope of this article but there’s plenty of research out there; when done properly, this isn’t about starving yourself to lose a few pounds, but fine tuning your satiety signals and improving insulin sensitivity.

Ok, so then what’s fasting mimicking: This plan “mimics” a fast by eating significantly fewer calories, and eating a macronutrient that will not affect your blood sugar levels (fat) like other macronutrients do (carbs and protein). You’re basically tricking your body into thinking it’s fasting, hopefully kicking off the benefits listed above, without being super hangry.

Why I did it: I had just come back from a gluttonous vacation and was still behaving as if I was on a gluttonous vacation when I got home. I could sense my regular healthy routine slipping, was feeling bloated, I was eating too much sugar, and I wanted a reset.

General gist: Eat about 40 percent of your daily maintenance calories, but have them come entirely from fat. So, if you normally eat 2,000 calories per day, eat about 800. I had a “regular” meal on Sunday evening at 6:00 pm, and had my next real meal at 6:00 pm on Wednesday.

During my three-day fasting mimicking experiment, I ate some variation of the following, throughout the day as needed:

· A high-calorie bulletproof coffee at some point in the morning (I used Fat Fuel because they are delicious but you can make your own)
· Another coffee or tea with emulsified MCT oil (I used Natural Force)
· A couple cups of bone broth (you can make your own or buy it pre-made)
· An avocado (liberally salted)
· Coconut oil
· Lots of water, with added electrolytes (I used Nuun tabs)

A few observations:

· I really wasn’t that hungry. There were definitely a few times I was bored and WANTED to eat, but I don’t think my stomach growled once during the entire three days.
· I slept better; probably because I didn’t have a surplus of energy/carbs keeping me up.
· I went to yoga or went for a long walk each day, but I wasn’t feeling my normal high intensity/heavy lifting workouts by the third day. If you were contemplating doing this for three or more days you probably have to sacrifice all but the lowest intensity exercise. Which also may be a good reset every once in a while, but not a good idea to plan a fast in the middle of any intense training. *(most of the research out there recommends at least three days to make sure you’ve switched over to fat burning and are reaping the maximum benefit, although I can’t imagine why you’d want to do this for more than 6–7 days, and there are definitely diminishing returns and issues with chronic, extended calorie restriction; do your research).
· It’s difficult to eat basically only fat and still eat “real food” (avocados have carbs; so does cheese; meat is mostly protein, etc). Each day I probably clocked in at around 10 grams each of protein and carbs which were basically unavoidable unless I wanted to just drink MCT oil all day, which gross. No. Another reason why this can be treated as a temporary reset, not an everyday thing.
· By the end of the three days, I was feeling less bloated, more “tight” (I looked leaner and could see my abs a bit more clearly). I didn’t weigh myself before or after but I know I felt and looked better.

Concluding thoughts: Overall, I think this was an effective protocol to achieve what I wanted: breaking the sugar/junk food/overly large portions cycle I slipped into, not worrying about food choices for a few days, giving my system a break, burning some fat, all without drastically lowering my energy or restricting myself. I would do it again, for 3–4 days, perhaps quarterly as a reset (after the holidays, maybe). I think it’s easier to adhere to than a strict, water-only fast.

I care less about being “keto” than about being metabolically flexible. I will always want to have healthy carbs (and some unhealthy ones) as part of my life, and I want to be able to use, tolerate, and adapt to both fat and carbs as needed. The idea of being strict keto, for me, is too restrictive, and unnecessary as it relates to my health state and physical goals. But the ability to “be keto” for a few days, or to burn fat readily, is an important and useful skill for our bodies to have, so this could be an interesting experiment if you find yourself relating to my story. I am not a doctor and am not prescribing this plan to anyone; consult with your doctor, do your own research, and be smart about your self experiments.

Next up: a 3–5 day carnivore diet, which may amount to the same thing as my fasting mimicking diet: there is some research saying that keto and carnivore diets may work well for people because it essentially mimics fasting (it’s really all about getting the sugar and processed crap out of your diet!) and personally, as a meathead, I think I’d enjoy a meat-only diet much better than fat-only one. Stay tuned, and if you have any questions for me, please comment below or each out to me on my website!