We’ve Been Wrong About Carbs

0:00 – 4:35

The Cortisol Revelation: Why Low-Carb Might Be Keeping You Stressed

Picture overweight and obese subjects sitting for an eight-week study, having their saliva tested 14 times a day while researchers threw psychological stressors at them. The group eating higher amounts of carbohydrates showed something unexpected: a dampened cortisol spike when stress hit. Not lower baseline cortisol, but a buffered response to acute stress. The carbs were literally telling the body that the threat had passed. The mechanism reveals the missing piece. When carb availability drops, your body manufactures glucose through gluconeogenesis, and it uses cortisol to do the job. Cortisol mobilizes glycogen, breaks down tissue, and prevents blood sugar crashes. If you're chronically low on carbs, cortisol picks up the slack constantly. When carbs come back in, even in small amounts that won't knock you out of ketosis, that pressure valve releases. The body reads it as a signal that energy is available, the environment is safe, and there's no need to stay in a stress-driven state. This isn't a subtle shift. The study tracked measurable changes over the full eight weeks. Your body is recalibrating its stress thermostat based on what you're eating. When the system senses scarcity, cortisol turns it up. When carbs come in, it tells the system to dial it back down. If you train hard or live a stressful life and keep carbs chronically low, you may be sustaining elevated cortisol that impairs recovery and hurts adaptation over time. After over 10 years on low-carb, the speaker's cortisol is in check—because he understands timing and strategic use, not blanket elimination.