Aside from a ketogenic diet, intermittent fasting — where you do not eat for 16 to 18 hours a day; 12 hours being the absolute minimum — is another effective way to regain your insulin sensitivity and control mTOR.
Basically, while you’re fasting, your insulin will dramatically drop, allowing your body to enter into autophagy and clean itself out. Then, when you refeed, your body deactivates autophagy and starts to rebuild itself.
Dr. Jason Fung, a nephrologist, recently published a case series paper4 on three diabetic patients — all of whom were on high doses of insulin — detailing how intermittent fasting can be used as a therapeutic alternative for Type 2 diabetes.
Of the three patients, two did alternating-day 24-hour fasts, while one fasted for 24 hours three times a week over a period of several months. On nonfasting days, they were allowed both lunch and dinner, but all meals were low in sugar and refined carbohydrates throughout. (The complete manual of the fasting regimen used is described in Fung’s book, “The Complete Guide to Fasting.”5)
Two of the patients were able to discontinue all of their diabetes medications while the third was able to discontinue three of his four drugs. All three also lost between 10 and 18 percent of their body weight. Incredibly, all were able to discontinue their insulin in just five to 18 days. Bikman comments:
“From the context of controlling insulin, there are studies on insulin-resistant people where they are on isocaloric diets, so the same amount of calories, but one is eating them frequently in smaller amounts and one is packing them in a smaller window …
Those on the time-restricted eating schedule … had greater drops in glucose and insulin. That, to me, is the beginning and end. As a guy who sees the relevance of insulin in any chronic disease … I just simply ask, what controls insulin?
Simply give your body a break from eating. Twelve hours should be what everyone does every night of the week, even if they’re eating three full meals. At least get that 12-hour break, for heaven’s sake.
As a professor, I see kids who live on cold cereal. They’re eating three bowls of cereal at midnight. [Then] they have the same three bowls of cereal at 7 or 8 a.m. I hear them, of course. They’re smug, ‘I can eat whatever I want.’ I say, ‘Let’s see how you’re doing in 10 years.’”
The reason you want to avoid eating for 16 to 18 hours is because you cannot effectively deplete the glycogen stores in your liver otherwise. As noted by Bikman, your liver will hold, on average, 100 grams of glycogen, and it takes anywhere between 24 and 48 hours to burn that up.
What this means is that if you’re eating a high-carb diet and want to get into ketosis, you’ll need to totally restrict carbohydrates or fast for at least 24 hours. Once you start running out of glycogen, your ketones will start to rise to take its place as a fuel for your body. Around 48 hours, you’re solidly in ketosis as the glycogen in your liver has been cleared.
On a side note, fasting will also release fat-bound toxins and facilitate detoxification. As noted by Bikman, “as insulin comes down, your urine production starts to increase,” as your kidneys start to flush out toxins.