Paul Saladino· MD
we can pass tryptophan across the blood-brain barrier with without carbohydrates in the diet we all do it every day it has to do with the amount of tryptophan so I can imagine that if someone a psychiatrist is saying that they're thinking about tryptophan moving across the blood-brain barrier and being a precursor for tone formation and tryptophan is also a precursor for melatonin production so in the book I answer this question as well but the it's not an issue of insulin but when we eat carbs insulin is released and that causes many of the long chain amino acids to go into the muscle and the relative concentration of tryptophan goes up well the interesting thing about a carnivore diet is you're eating lots of protein and the relative concentration of tryptophan also goes up it's just about the relative concentration of tryptophan relative well in comparison to the large neutral amino acids that gets tryptophan across the blood-brain barrier it's not insulin dependence