Does Keto and fasting increase stress hormones?

The answer is no.

Some people believe that it appears to be stressful on the body because you're starving the body of glucose. But, a person has fat on their body to be used as fuel. I believe it's logical that our bodies are meant to run off of fat between meals.

Cortisol is a stress hormone. Cortisol is also called glucocorticoid. One of the big functions of cortisol is to keep your blood sugars from getting too low. It will release stored glucose or cause the production of glucose to maintain the blood sugars. This isn't a stress event. It's a normal thing that occurs in the body.

It takes about three days for the body to start adapting from burning glucose to burning fat. Cortisol can rise a little bit when a person goes through the three-day keto-adaptation phase, but then it levels out.

When you run your body on glucose, it is very stressful for the body, and you can't tap into your own fat. But, when you get into ketosis, you could go from a stress state to a much higher level of calmness and state of well-being. Burning fat or being in ketosis is a non-stressful state. Keep in mind, when you start keto and fasting, it's important to take electrolytes and B vitamins.