"Mimicking" the Fasting Mimicking Diet (my self experiment)

I’ve posted a lengthy writeup of my recent experience replicating the “Fasting Mimicking Diet”, based on a study that was published in Cell Metabolism (and funded by the National Institute of Aging), where researchers found that cutting daily calories in half for just 5 days every 30 days reduced biomarkers for aging, diabetes, heart disease and cancer with no adverse effects.

The main guidelines are:

  • Day 1: Total caloric intake of 4.5 to 7 kcal/lb of body weight (10% protein, 56% fat, 34% carbs)
  • Days 2-5: Total caloric intake of 3 to 5 kcal/lb of body weight (9% protein, 44% fat, 47% carbs)

Which for me translated to 774 total calories on day 1, and 516 total calories on days 2-5

I was able to lower my fasting glucose from the low 80’s to the mid 40’s (mmol/dL) while steadily moving from “nutritional” ketosis to “optimal” ketosis.

I experienced a slight loss of weight and body fat while maintaining muscle mass (usually fasts have a catabolic effect), and huge rebound effect to testosterone upon refeeding. And such vivid dreaming and mental focus!

My post contains a lot of data points (along with the Google spreadsheet I used for the experiment).

Has anyone else done any fasting-related experiments?


Bob, thanks for posting this. I started following your blog this year and am consistently impressed by the thoroughness of your experiments and documentation…I’m not aware of any other bloggers applying as many quantified self tools with as much scientific rigor. Congratulations!

Regarding your post, I have to think that the amount of fat loss and the fact that you registered a gain in protein must be an artifact of the scale you are using. I read a research study where resistance-training athletes on a high-protein diet gained about 1 pound of muscle mass in a month.

You mention that you are already keto-adapted because you practice intermittent fasting. Can you say more about that, or link to a post?


Hi Conor! Thanks for the kind words. What I actually said was that I wasn’t as keto-adapted as I had thought. I’ve practiced intermittent fasting on and off over the past few years but it can take 2 weeks to 30 days of straight high fat, low carb (HFLC) eating to create a metabolic switch to ketones. That’s why after my experiment I fell out of ketosis so quickly!

I previously wrote a bunch about intermittent fasting in this series of posts:


I agree about the (in)accuracy of most body impedance scales and various factors that can effect body fat readings (moisture on feet, weighing oneself too quickly after waking up and not allowing fluids to re-distribute throughout the body after lying down/sleeping for several hours). Thanks!

I have been tracking a lot of my numbers while doing the FMD once a month for six months (w/ one 5-day water fast in the third or fourth month). I have had great results. I know the point is not weightloss, but i have lost 15 pounds. As far as health markers, my A1C has dropped into the normal range, hemoglobin levels have improved, cholesterol has been cut in half (although it was at a worrisome level before I began), and my blood sugar gets lower everytime I do a fast.

I experimented with the macros, too, in order to make the food a bit more appetizing. So far, I stick to the calories as prescribed, keeping protein low and zero animal protein, and have the same biomarkers improve as Longo’s study suggests. Maybe someone has an answer to that but I’m guessing the calorie restriction and Ketosis are reaponsible despite departing from Longo’s macros?

I recently have started using a company named Lifebox, too. They kinda take the brain work out of it and send you a subscription box with all the food you need for a 5-day FMD. Works really well for me on weeks when I am pressed for time and just need an easy way to run my fast. Their website is here: https://www.lifebox.diet

Thanks for questions or replies in advance!

Hi Grant
I think you are doing well. The A1c marker seems to be the best predictor of a number of acute diseases. My biomarkers were normal but excess weight was a concern. My BMI is now 27 down from 32 (May 2014) and I hope to stabilize at 24. Hormones play a key part in setting weight and the best way to reset hormones is by water-only fasting. I have found there are many other benefits as well. Once your body has adapted to burning fat (ketosis), water-only fasting is not that difficult. You will find not eating is quite a time saver. If you want to look into it a bit more, I found The Obesity Code by Jason Fung MD readable and science based.
best regards
John Robertson

1 Like