I've found BCAAs to be pretty useful when exercising, in both anaerobic resistance and aerobic endurance settings. There's something about sipping on some branched-chain amino acids (even after I've had a meal) that gives me increased energy and motivation in the gym. I've read these amino acids can be directly oxidized by the muscles with a anti-fatigue effect on serotonin receptors. In the past, I was exercising in the morning fasted, but lately I've been doing this a few hours after lunch (~100g of fat @ 1,000kcal+ with a small amount of protein from greens + nuts + avocado) while still including my BCAA intra-workout mix.
I found these articles which make me question whether I should drop the BCAAs:
Too Much Protein, Eaten Along With Fat, May Lead To Insulin Resistance -- https://www.sciencedaily.com/releases/2009/04/090407130905.htm
High-protein diets are associated with impaired glucose tolerance, insulin resistance and an increased incidence of type 2 diabetes. These findings are in agreement with studies showing that the infusion of AAs induces insulin resistance in experimental settings, similar to what is observed with lipid administration. The addition of BCAAs to a high-fat diet contributes to the development of insulin resistance, impaired glucose homeostasis that can occur independent of body weight. In the case of the amino acids, we also are finding increased levels of their metabolic breakdown products, which suggests the whole system for handling the amino acid metabolic process has been overloaded -- our rat studies show that this overload causes changes at the cellular level that can lead to insulin resistance. Insulin resistance occurred in animals with a diet high in the branched-chain amino acids, but only if they were ingested along with a high level of fat in the diet.
What are your thoughts on supplementing intra-workout BCAAs in the context of a high fat diet?