Experiment Fasted Training



This experiment is based on Dr. Jason Fung. and his 3 books.

So Ive tried fasting for a while now and have done 6.5 days 3 times. My definition of a fast is nothing but liquids mainly water, club soda or sparkling water. It is not a complete fast because I take in around 100 calories a day using electrolyte tables and the like. So not a true fast! I was also taking cream in my tea a few times a day but have stopped that.

Today I am at day 8 of this fast.
I’m hoping to share this information and document my journey and maybe help others out! Or freak them out not to do it :slight_smile:

About me. I started cycling in a June of 2017 at 265 lbs. When winter hit last year I bought a used tacx vortex and quickly started using trainer road. In 2017 I rode approximately 7000 km and this year I will break 12000 km. I turn 50 in February and currently my ftp is at 292.

So here is my last week and a bit.
Nov 9

Nov 10

Nov 11

Nov 12

Nov 13

Nov 15

Nov 16
Tech gym bike Bike at hotel
50:37 41 tss
Nov 17

Nov 18

Nov 19

I’m about to start sweet spot mid base II tomorrow. Thank you to forum users for pointing me in the right direction!!!

My weight tracking is
Nov 9 214.9
Nov 12 211.3
Nov 13 207.2 Between Nov 9 and Nov 15 I was losing a lot of water from my body from everywhere.
Nov 14 205.9 Now that that period is over weight loss has slowed but is progressing well.
Nov 15 202.3 I feel great and plan to continue this for a while.
Nov 17 198.8
Nov 18 198.2
Nov 19 196.9

I see my family doctor this week and will get a quick checkup and blood work done.

A calorie calculator tracked me at 2361 calories per day to maintain my weight. Depending on the day I am negative between 2261 and about 3450.

I’m enjoying this so far. My withings smart scale says my goal weight is 145 lbs. I have not weighed that since grade 5 so I do not think that is possible. But 160 would be nice and I would also like to get my ftp up to 320!
If the ride links aren’t showing up properly please let me know how to fix.


Thats a lot of weight loss in a short timeframe. From all I’ve read about rebounding, maintaining strength, easing body to new set point, etc, I’m not comfortable losing more than 1lb a week, or 4lbs a month. Stay safe!


Looking at the workouts you linked, you’ve done almost no work at higher intensity. What progress are you making to actually raise your FTP?

I bet you’ve dropped a bunch of water weight due to using up all of your glucose stores, but at what cost to your training? I’d rather focus on fueling my quality workouts to raise my FTP, personally.


The workouts I’ve shown have nothing to do with upping my ftp. Ive shown you the last week of sweet spot base mid 1. I just finished it as that is where I was in the program. I have dropped a ton of water weight!!! Mostly water to be sure. As for trying to increase my ftp that I hope will happen on this next training cycle starting tomorrow.

I’m hoping to be able to handle the increased work load as this new program starts. But if I have to much trouble with it I will lower the intensity. At this moment I am more concerned with dropping the next 37 lbs than increasing my ftp. At some point in the next 3 months I am going in for hernia surgery. The less I weight the better it will go. In 2 months I will lose a lot of power that will have to be built back up.


Yes this is common theory. In Dr Jason Fung’s the complete guide to fasting he goes through this scenario for people training. It should not be a problem at all (I hope). But I will be seeing a doctor often.


Nov 20
Ftp test. Dropped 6. Was damn hard. max heart rate went to 180 when my age says it should top at 171.
weight 195.8 Calories in 50


6pt ftp drop is just statistical noise, nothing to worry about unless the next one is even lower.

The age-based HR rules are a load of bupkis. Sure, generally it declines with age, but it’s describing a population effect, not your personal range. Figure yours out from experience, and go by that. One thing to consider if your HR is higher than normal, you could be dehydrated. More salt and water are in order. And since you’re fasting, that’s very very likely.

Instead of linking all your workouts, you can just link to your calendar. I can pull it up just fine. And your career page.

Big fan of Dr. Fung’s work. I don’t really do any extended fasting, but his blogging a number of years ago really put me onto low carb and keto. Can’t fast forever, obviously, but carbs are definitely not necessary, even for cycling. Usually I’ll try to have some eggs morning of a race, but had my best cx race by far on Sunday skipping lunch and breakfast for a late afternoon race. Anyway, stick with it! Impressive results.


Thank you for your insight and support. Last night for the first time I noticed dry mouth. So You nailed it. Doubled up on my electrolytes and will have some bone broth today with extra salt!.
here is my calendar

Nov 21 194.6 lbs My ass is really starting get sore on rides. My longest ride this year was 11 hours and 311 km. I’m have trouble staying in one place and not sliding all over the place. I really hope this is temporary. Starting to miss the weight down there maybe!
Felling fairly good. A little soreness in the legs. Tomorrow is a much harder day so we will see…

so how do I link my calendar properly?


More salt, that’s my secret weapon for this year. If you want some reading material on it, checkout “The Salt Fix” by Dr. James DiNicolantonio.

Calendar link works. The preview isn’t very pretty, but I think it’s something to do with having to be logged in to trainerroad.com and how the forum software generates the previews. In general, if someone links a ride, you can also click on their name on that ride and it takes you to their career page.

You may find a new saddle or bibs are in order as you shrink. My longest rides are up to 150mi, and I think at the duration there’s no getting around a sore rear.


Nov 22
194 lbs
Rode Ebbets today. Left ftp at 292 and did not change to 286. Legs started hurting early about 15 minutes in but made it through. Feeling better overall with a lot more water intake. Not going to link the workout as my previous links should work to get there.
Should be in a 2919 calorie deficit today. Feeling pretty good with a little more back and leg soreness. But I have not done any bodywork on myself.