IF is intermittent fasting. The above says that IF improves cognitive function, reduces resting heart rate, reduces blood pressure, reduces inflammation, increases muscle efficiency and increases stress resistance.
Well, what exactly does fasting do? There's a bunch of links in the article, but in a nutshell, fasting about self-cleaning. Not just spiritual self-cleaning (which is, in my opinion, overemphasized in the article), but more importantly also physical and biological self-cleaning.
A period of fasting is a period in which the body doesn't get all the nutrients it needs. That forces it to reduce vital functions to a bare minimum, and eliminate non-vital functions. With perhaps surprising results: it makes you healthier than before!
Example: Fasting combined with a particular diet (hard-bread-evenings-only-for-a-week) will kill off all unnecessary intestinal flora, allowing you to regenerate the 'good' intestinal bacterial flora and kill all the 'bad' bacteria. That results in more efficient nutrient uptake and leaves you energized, even if you eat less.
Example: "When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged," Dr Longo says. Prolonged fasting reduced the enzyme PKA, which is linked to aging and a hormone which increases cancer risk and tumor growth. It promotes stem cell-based regeneration.
Example: "What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?" So, fasting causes an immune system boost, and the red blood cells needed to transport blood return after you are done fasting, to restore oxygen transport to your previous levels.