This is an interesting article. I like to skim these studies. After a little diving, the study results were from about 25 “world-class” race walkers. (30 actually, but some results were disqualified) Now, I know very little about this discipline other than you have to keep one foot on the ground at all time and it generally uses more upper body strength.
The athletes were on a typical keto diet (which I could not find specifics) for a “strenuous” 3.5 weeks of exercise. Data collected in a fasted state in the mornings.
The study references a bunch of earlier studies and doesn’t seem to show any work other than data collection and a conclusion based on said data.
I couldn’t find the type of exercise they were doing. Maybe someone more intrepid in study diving could, but I wonder if any weightlifting was included in this process. Could the keto diet completely negate the bone health gains from weight lifting? Cycling is even more low impact than race walking, but as of late, most cyclists I know include or suggest some form of weight bearing exercises to, at minimum, maintain strength.
Not to discredit their findings in any way. They state themselves that this is all just a data driven hypothesis and they hope further, more specific studies, could be funded.
Side note, as I realize I didn’t update this as much as I intended:
For myself personally, I had the best results (weight loss AND ftp gain) from an OMAD style diet consisting of a giant mixing bowl of greens, chicken, and an egg or two. Other ingredients varied based on what we had around the house/garden. Also, lots of black coffee! I kept the fat relatively in check most of the time. I just ate a vast amount of veggies.
I went from 220 ftp to around 280 in a 3-4 month period and dropped 50 pounds. Went from 265 to 215-20.
My race went well for the first 3 days. Multiple firsts for me. First double century and first 10k ft of climbing in a day. In the end I had to drop out due to knee pain, but I’m planning a comeback in 2021!