Subjects (n = 38, 19m/19f, age = 25±9 yrs, BMI = 25.0±3.3 kg/m2) reported to the lab fasted and ingested either a high-carb (-C) or a high-protein (-P) meal before half of them performed a computer based stress test (S-), while the other half served as a "rested" control (R-). Groups were changed and the procedure was repeated.
|Figure 1: Salivary cortisol concentrations (mean±SEM) at six time points (0, 30, 80, 125, 155, and 205 min) throughout the four test sessions: rest-carbohydrate (RC), stress-carbohydrate (SC), rest-protein (RP), stress-protein (SP); for men (n = 19, M) and women (n = 19, F). (Lemmens. 2011)|
To be fair, one must however say that the picture might have been a different one if the "stressor" had been an intense weight bearing or endurance exercise. Exercise induced hypoglycemia, for example, would unquestionably have induced a significant amount of cortisol release. Yet, my personal experience tells me that you generally do not run out of fuel if you follow a consequent low carb diet. I tend to run into problems (hypoglycemia) only, when I overdo on carbs - a consequent low carb diet, on the other hand, provides me with a steady stream of energy.