Hi Leslie! I appreciate your response. I have a strong understanding of human physiology and the advice given in this article comes from several studies as well as my boss who has a Ph.D. in Exercise Physiology (https://miketnelson.com/).
Yes — absolutely agree about calories and where they come from. I’ve spent years working with clients, though, who eat well-balanced, low-calorie diets who still have trouble burning fat. If they get tested at a metabolic ward (many do), you can see their bodies switch to burning carbs relatively quickly as intensity increases.
“Relation of adipose tissue to metabolic flexibility” Sparks, et al. 2008
Goodpaster B, Kelley D. In: Metabolic inflexibility and insulin resistance in skeletal muscle. In Physical Activity and Type 2 Diabetes. Hawley, Zierath, editors. Champaign: Human Kinetics; 2008. pp. 59–66.
#1. Sorry you found it vague.
#2. Yes. I agree. Insulin can in fact be thought of as a fuel selector switch. I did not come up with that term: “Metabolic flexibility in the development of insulin resistance and type 2 diabetes: effects of lifestyle”
#3. That was a mistake that I’ve corrected. Thanks for calling my attention to it.
#4. I’m a believer in meeting people where they are at. My clients aren’t necessarily going to give up a small piece of candy. I can ask them to all day long, but ultimately 80–150 calories before a workout is not a big deal and it can keep them motivated to stay on track.
I’m not sure which meta-analysis? I have access to my boss’ pub med account, so I may be able to see full text when others potentially have to buy the study. I’ll see if I can get you a copy.
Yes, theoretically no one would over-eat and sugar would be outlawed. I also can’t ignore that some people have issues burning fat at rest and at low intensity. This is also a really great study: https://www.annualreviews.org/doi/10.1146/annurev-nutr-071816-064634?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed