Research perspective · 2 October 2026
Carbohydrate intake can change cortisol metabolism
A human crossover study separates dietary composition from weight change.
What the research found
Crossover studies in 17 men and a six-man isocaloric group compared 66%-fat/4%-carbohydrate with 35%-fat/35%-carbohydrate diets. The very-low-carbohydrate diet increased cortisol regeneration and reduced clearance, without changing plasma cortisol or its salivary rhythm.
What it does not establish
Subcutaneous abdominal 11β-HSD1 was unchanged. Small male-only studies do not demonstrate clinical harm, abdominal-fat gain, or a benefit from a particular EPK prescription. Neither comparator was a 20%-fat diet.
A research question for EPK
Diet studies should distinguish cortisol production, regeneration, clearance and measured concentrations. EPK could test whether diet composition affects these processes independently of energy intake, while assessing actual function and body composition.
Research and guidance
Explore more studies in the research library.
Related working papers
Read the relevant PDFs: EPK–001 to 007 are the revised version 1.2 papers; EPK–008 to 010 are version 1.0 supplements. Earlier PDFs and DOI records remain on the paper archive.