Extract:
Wolf doesn’t ...... cite a single study that contradicts the connection between low-carb and cortisol. He simply trots out the tired old “fat adaptation” nonsense, claiming that the heightened cortisol response to low-carb diets documented in the research is simply an artifact of a sudden change in diet.
Wolf claims this observation is simply a “stress” response experienced by people who are used to following high-carbohydrate diets. He claims that once these folks become adapted to a low-carb diet replete with protein and fat, a wonderful phenomenon known as gluconeogenesis (the creation of glucose from non-carbohydrate sources) will kick into high gear and keep a lid on cortisol.
This is an especially fanciful claim when one considers that cortisol is a potent stimulator of gluconeogenesis [Khani].
Indeed, that’s one of cortisol’s key roles in the body; to increase energy availability via glucose production and liberation of fatty acids when blood glucose and glycogen levels are inadequate (which is exactly what occurs when dietary carbohydrate is deficient).
In Wolf’s fantasy world, gluconeogenesis magically involves only glucagon but not cortisol. In real life, when dietary carbohydrate intake is manifestly inadequate (such as in hard training athletes attempting to follow a low-carb diet), cortisol release is heightened, which in turn increases both glucogeonesis and the release of fatty acids.
Article headings:
- Low-Carbs, Glycogen Depletion and Cortisol
- Decrease Your Carbs, Increase Your Cortisol
- Low-Carb, Cortisol and Immune Function
- Carbohydrates versus Overtraining
- Physiological Reality Gets in the Way of Dogma Again
- Low-Carb Vindicated? Not So Fast
- Wolf Supports His Cherry-Picking Claim by…Cherry-Picking
Conclusion (extracts):
If you are sedentary or only moderately active, a low-carb diet may or may not increase cortisol.
If you are a hard-training athlete performing high volume glycogen-dependent activities, then attempting to follow a low-carb diet is almost certain to lead to cortisol elevations and suppression of immune function. Given that there is no performance advantage to low-carb diets (in fact, the exact opposite is true), then there is simply no reason for any intelligent athlete to be following such diets.
Given that one of the effects of heightened cortisol is immune suppression, the link between low-carbohydrate diets and increased cortisol is a very real concern that should not be flippantly dismissed because it conflicts with certain people’s preciously-held dogma. Thanks to the clear connection between low-carbohydrate, higher cortisol and worsening immune markers in athletes, Cupps and Fauci have pointed out that athletes deficient in carbohydrate are placing themselves at high risk from the known immunosuppressive effects of cortisol and falls in glutamine availability, including suppression of antibody production, lymphocyte proliferation and natural killer cell cytotoxic activity[Cupps].
By antagonizing testosterone and increasing muscle breakdown, heightened cortisol levels are also anathema to the anabolic state required to optimize recovery from training and preserve or even gain muscle mass.
The research... speaks for itself. Fat adaptation cannot be used as a catch-all excuse to explain away negative low-carb results, and increased cortisol levels can indeed persist beyond the initial fat-adaptation phase of low-carb diets.
Listening to Wolf’s podcast, it’s clear he is exasperated at those who cite the low-carb-cortisol connection. My advice to Wolf: switch to decaffeinated, eat more carbs, and study the research a little more thoroughly before unfairly accusing others of cherry-picking – especially when you are guilty of doing just that yourself.
