First of all, great work. Your article was full of information and very well-written. That being said, as a Wellness coach who does I.F. on a weekly basis and engages in strength training (mainly deadlifts), I find that you are missing a few important points in your article:
a) Insulin is only one of the many hormones that plays a role in health and influenced by I.F. The most important hormones that you should focus on when talking about I.F. are Ghrelin and subsequently leptin.
I.F. can also benefit estrogen dominance by lowering body fat. Also, low fat levels mean higher testosterone levels.
On the cons side however, I.F. can increase cortisol under stressful conditions. High cortisol levels will melt away your muscle and store fat, which is not something that anyone wants. (Plus, it depends on your personality, hormonal profile and your existing stress levels).
b) You mention in your article that there is a “study done on people who fasted which proved there was no muscle loss”. I would love to see a link to that study(ies). I am honestly really curious about the participants, levels of activity etc.
I love reading medical studies however, some tend to be a bit biased and in some cases financed by the wrong end. Take everything with a grain of salt, I always say.
c) Also you mention that you “work out fasted and have seen no muscle loss.” This is a far-fetched comment since it is a bit difficult to track body composition without numerous DEXA scans, muscle fiber count/samples or at least a series of progress photos over a period of 3–6 weeks. If you have this info, please post it and share your experiment with us as this will provide excellent insight and proof for the article. If not, keep in mind that the scale and the mirror can lie so please refrain from using such statements.
d) As for “feeling no energy loss while working out fasted,” that is true mainly because your adrenals are keeping you up. Relying on your adrenal for such a task is not a healthy situation, especially if you are training heavy and hard! (You won’t like it when you come face to face with adrenal fatigue, trust me)
Also, different people have a different understanding of the term ‘working out’ based on their fitness level and experience with exercising. For me working out includes heavy lifting and/or high numbers of bodyweight exercises performed for a minimum of 45 minutes at mid to high intensity. Anything less than that, I call it a warm up or active recovery.
I don’t count my daily 30 mins of yoga as a work out. For me that is a warm up. For other people, that may count as a work out. In this case, I expect no significant energy loss as this is a non-adrenaline based activity and no glycogen is depleted. In the case of heavy lifting though, I have tried it and found it to be a horrible idea.
As a final note, again, great work on the article. My comments are meant to help you improve your work, not undermine it. I am somewhat sensitive when I read good articles that leave out important pieces of information. But like I mentioned earlier, as someone deeply involved in heavy lifting, I.F. and hormone optimization, the above points need to be addressed for completeness and accuracy.
Nick Sigma C.W.C.