The four stages of fasting.
Most popular forms oftime-restricted eating(TRE), such as16:8or18:6 fasts, alsocycle between these two stages2of fasting.
During this period, your blood glucose levels increase as your body digests and absorbs your meal.
There’s a shift in the levels of a few other hormones around this point as well.
For instance,ghrelin3a hormone that makes you feel hungrytends to drop one to two hours after eating.
On the other hand,leptin levels increase4during the fed state, making you feel full.
It’s also partially responsible for thefat-burning benefits of fasting.
This can also be achieved without fasting, usingvery low-carb dietslike keto.
This basically means that your body is being powered by ketones instead of carbs because you’re not eating.
It can also be influenced by your usual diet.
In fact, one study showed thatmarkers of autophagy were detected11in white blood cells after just24 hours of fasting.
Plus,levels of mTOR, a protein thatblocks autophagy12, are also decreased during this stage.
Impressively enough, some researchers even believe that enhancing autophagy couldextend the life span14and slow signs of aging.
Several other benefits have been reported in long-term, medically supervised fasts.
Exercising during a fast.
Just as important aswhat you eat after you exerciseis what you eat (or don’t eat) before.
“There have been afew studies19in alternate-day fasting combined with exercise,” says Gabel.
Breaking a fast.
When to stop fasting.
Frequently Asked Questions
What does a 72-hour fast do to your body?
A 72-hour fast may alsopromote autophagyand alter levels of certain hormones, such as insulin.
What is the ketosis stage of fasting?
Ketosisoccurs when your body begins using fat as its primary source of energy rather than carbohydrates or sugar.
