Worst article on diet ever?

rheddmobile

That's a bizarre article, all right.

One of the specific things it gets wrong is the effect of cortisol - which does increase during fasting, for many people. The article says cortisol lowers blood sugar. What it actually does is block the effect of insulin, temporarily raising blood sugar, or more accurately, preventing it from dropping any lower.

Healthy people should be well able to maintain a consistent level of blood sugar despite skipping a meal or two. You have a liver which stores and releases glycogen at need. Your muscles also store glycogen.

As an official not-healthy person - type 2 diabetic - I test my blood often during the day and get to see under the hood how my body responds to different circumstances. For example, like many diabetics I get something called Dawn effect, a burst of high blood sugar first thing in the morning before eating, caused by a rise in cortisol which the body does to wake you up and give you energy after the night's fasting. Not all diabetics experience this effect. Which is one reason the article is so silly, even among people with the same illness, no two people react to fasting in the same way.

Normally when you eat carbs, they enter your bloodstream and your blood glucose rises, quickly matched in healthy people by insulin metabolising those carbs for energy, so a healthy person's blood sugar remains almost level. But a diabetic either doesn't produce enough insulin (type 1) or the insulin doesn't work properly (type 2) due to insulin resistance, so when a diabetic eats carbs the levels go up to unsafe levels and stay high for longer than they should. It's typical, therefore, for a diabetic to have lower blood sugar before eating a meal full of carbs than after. But due to the dawn effect of stress hormones, when I eat breakfast, my blood sugar actually DROPS after eating, because my cortisol levels drop, thus allowing my insulin to get in there and do its job.

I've also read about diabetic runners who are able to use their cortisol levels for emergency blood sugar control if they feel their sugar dropping too fast during a run - by sprinting really hard for a short burst, some people can increase their stress hormones enough that their sugar will stop dropping temporarily, allowing them enough time to get home and consume some quick carbs. Sounds risky but better than passing out in the street! So, running makes glucose levels drop, but running really hard may (depending on the person) make them rise.

My primary point here is that the body's response to fasting is a) complicated and b) different in different people.