There are several schools of thought on fasting. A popular rule of thumb is that one can consume up to 50 calories during a fasting period without breaking the fast. If you subscribe to this principle, a serving of IN-Perium is nowhere close to ending your fast. Some people, including Dr. Jaquish, would also maintain that the benefits of fasting are derived from the absence of an insulin response. If you are participating in an insulin restriction fast, you may be pleased to know that a majority of the 25 calories in IN-Perium are from fat, which causes no insulin response. The concept of ‘insulin fasting’ is the basis for substituting coffee with butter and MCT oil for an ordinary breakfast, and you can make the same substitution with IN-Perium. Furthermore, if one is fasting in an effort to promote autophagy, it is worth noting that ingredients in IN-Perium may well accelerate the onset of that process. Studies have shown that caffeine itself and decaffeinated coffee both promote autophagy in mice [15][16], and observational evidence discussed in that research suggests this effect may occur in humans as well. IN-Perium contains both caffeine and coffee extract. Likewise, research suggests that ketone bodies may promote autophagy[17], and the body can easily convert the MCT oil in IN-Perium to ketone bodies following consumption.