Solid base vs unstructured training - case study with results

I promised in another topic to do some analysis based on the results of respiratory gas analysis during a ramp test I’m doing as a part of my annual health check. The sports testing center I’m doing my checks is kind enough to provide me all the raw data, so I was able to nerd out a bit and reach some interesting conclusions.

Both tests were done at the same lab, using the same equipment - all the data, including power comes from the same source.
Based on the VO2 and VCO2 volume, I was able to calculate the fat (FT) and carbs (CHO) metabolism at various levels of effort and compare both years.

March 2017 test - 189cm, 75kg
The test followed a 4 month period of very focused training - I started in November 2016 after a bike crash, did a vast majority of my rides inside and 95% of my workouts were done fasted. The main training blocks I did we sweet spot base 1 and 2 on TR. In terms of diet, I kept my macros in check throughout the whole period - no refined sugars, 30% protein, 20% fat, 50% carbs.

June 2018 - 189cm, 77kg
I changed jobs in October 2017, I was riding lots but none of that was structured. The main reason was simply flying back and forth between California and Europe and a resulting jet lag at least twice a month - my new job gave me the opportunity to ride my bike in loads of cool places, I made a few efforts to structure my workouts but essentially I rode on TR when I was not able to take my bike with me on work trips on when I was back at home “enjoying” the European winter. TR workouts were sporadic and not structured. My diet was probably the biggest issue - I keep relatively clean, but even my short workouts were fueled by copious amounts of carbs, outdoor rides were mostly fueled by ice cream and cake (I blame the Californian cycling culture for that!).

Here’s how the both base phases looked like in terms of structure:

*November/December 2016 - I was testing other indoor platforms back then, all rides were indoor but they show as other on TR. I was following the Racing Weight Quick Start Guide 6 week plan.

And here’s how this affected my metabolism on the bike:

I did the 2017 test 3 hours after easily digestible lunch, in 2018 I did have one caffeinated energy gel just before the test and I had an energy drink in my bottle.

As you can see, the results are quite dramatically different, my FTP in both cases was approx 310W, but in 2018 I was burning huge quantities of carbs just from the beginning, which resulted in some pretty miserable performances during the few races I participated at.

Below is the link to the full calculations just in case someone is interested, I did some digging to get to a decent research on the subject, but it’s possible I made errors in my calculations. If that’s the case, feel free to correct me.


Interesting read, thanks for posting.

I would love to have access to find my CHO/FT burn rates at given intensities. I do have a facility close by that offers VO2 testing and other profiling, maybe I’ll drop them a line…

Slightly off-topic but I feel it relevant to reflect how the macronutrient composition of foods ingested can & will influence burn rate.

It’s a two part read but really isn’t long or complex, very easily understood. It compares two atheletes with either predisposition for CHO/FT and re-evaluates this after following a HFLC diet for 8 or 12 weeks (I think).

The high CHO pre & post.

The athelete with the greater preference for fat pre & post.

Part 1

Part 2


@konradkowara thanks for posting, I bookmarked and forgot to ask a question. What testing was done? We have a local training center that has lab equipment for lactate, VO2max, and HR/power training zones. They have a Parvo Medics TrueOne metabolic monitor to measure gas exchanges, from your second paragraph it sounds like having VO2 and VCO2 is enough to calculate fat and carb usage.

That’s a very interesting read, thanks! I took my data and plotted it in the same way as represented here, this is actually even more telling.

Balanced diet and structured base:


Carb extravaganza :man_facepalming::

I think it’s fair to say but even when I’m specifically training fat adaptation, I’m still very much carb reliant, but neglecting this training makes for a very extreme example.

This actually explains very neatly what happened to me this year during the Maratona dles Dolomites. I assume I have about 1500 kcal worth of muscle glycogen on board, I fueled with 80g carbs an hour (so that’s 320 kcal an hour) plus my pre-race breakfast was 120 g of carbs (480 kcal).

First 4 hours I felt great, I was doing a pace that felt really easy and I was planning to speed up in the last part: (notice the TEE at 2852 kj)

Around the 4 hour mark I started feeling gradually worse, I somehow battled through the climb, stopped for a few minutes and ate some more food, though the descent would help me recover, but I still crashed and burned at 5 hour mark (at 3496kj):


Sorry for the long anecdotal plug in, but it kind of clicked for me now.


The testing was done in a training center in Amsterdam, Netherlands. The equipment they are using is Cosmed Quark with Omnia Metabolic module. The protocol is a graded test very similar to TR Ramp test actually, the full protocol name is GLI (Spirometry), Wasserman extended. Not sure if it helps but maybe good to know :slight_smile:
Your local training center will have a different soft/hardware, but that should not affect the results as long as it’s consistent. What’s important is that they are able to give you the raw data to play with.


Great stuff, thanks for sharing the story too!

I downloaded the spreadsheet, are you using standard (easy to find) formulas to calculate fat and carb usage from VO2 and VCO2 data? Thanks again!

Yes, I’m using formulas I found repeated in a few scientific papers. E.g.:


Thanks for this.

I had palmed off a VO2 max test as it interested me but has no direct application to my current training (periodised rather than polarised).

However if I can obtain VO2 and VCO2 values and estimate my CHO/FT rates reasonably accurately I’d value this quite heavily as I’ve always been curious. I’m fairly certain I’ve good fat adaptation/utilisation evidenced in my ride fueling strategies but some more concrete confirmation would be useful.


Reviving an old thread on fat vs carb. I found the following article to be interesting.

The main takeaway for me is that to increase % of energy derived from fat, longer durations are more important than riding at any specific intensity.


I’ve had similar experiences in my longer rides. Around the 5 hr mark things start to go south for me where RPE increases, and power output drops.

Similar to your experience, I think this corresponds to the point where I run low on glycogen.

One of my main training goals this year is to improve the amount of energy I can derive from fat metabolism. Want to avoid a similar fate this year during Leadville!