MyQul
Chairman of the Bored
Resetting the immune system sounds a bit pseudo-sciencey to me, and if you read the studies there's not a lot of evidence to support it. The majority of this research has been done on mice, which often has limited transfer to humans. The bit that was carried out on humans was in a very specific setting (chemotherapy side effects) and had a sample size of only 10, only 6 of of which reported a reduction in side effects. Also as was pointed out, this was for a 48 hour minimum fast which certainly is hardcore. That being said, I think the 5:2 diet is without a doubt a great way to lose weight and to keep it off, because compliance is probably easier for most people in comparison to other calorie restricting diets.
Your right the phrase 'resetting your immune system' does sound pseudo- sciency but what fasting can also do is increase autophagy which is basically cleaning out damaged cells to regenerate newer healthy cells. From my understanding old dead cells are consumed by healthy cell and new ones are grown. Below is an article about autophagy and fasting. It doesnt specifically talk about the immune system but if white blood cells are also recycled and grown alongside other cells in the body using autophagy , the immune system can possibly be 'reset'? But whilst the immune system is specifically your white blood cells. I think Lower blood pressure, lower blood sugar reduced inflammation will all support a robust immune system. These can also be done with fasting
https://www.healthline.com/health/autophagy#diet
Theres defiantely not enought research into this (as I mentioned above) as there no money in researching fasting. It's only really places like universities that get research grants that might do research into it.