The study I posted earlier about the hunger hormone showed that the hunger feelings during fasting are psychological instead of biological. The levels of the hunger hormone ghrelin go down. Therefore training the mind to remove the psychological hunger is feasable.
"High levels of the "hunger hormone" ghrelin have an antidepressant effect, US researchers claim. Blocking the body's response to ghrelin has been suggested as a weight loss treatment but it may also produce unintended effects on mood, they said." -- http://news.bbc.co.uk/2/hi/health/7453516.stm
This suggests that the regulation of ghrelin levels during fasting causes depression.
And it explains why people have reported feeling so bad during day 2 and 3 of the fasting. Fortunately even the depression effect is psychological. The ghrelin levels drop after having eating a big meal.
"When ghrelin levels in the stomach rise, the brain gets a signal that it is time for food. Ghrelin also slows our metabolism, just in case we cannot find any food. Then, after a big meal, ghrelin levels drop and metabolism speeds up to the burn calories we just ate." -- http://www.foxnews.com/health/2014/05/0 ... ssion.html
To cure the hunger depression, mindfulness can be used to train the mind to recognize the fasting periods as having the same effect as when eating food. The depression comes from habitual worry about not finding enough food, such as in ancient times. With intermittent fasting the actual situation is the opposite of uncertainty of having enough food. With scheduled intermittent fasting we know precisely when we will start eating again. So instead of having the body and mind struggling with ghrelin levels, mindfulness is used as a means for calming down the mind's habitual tendency of causing ghrelin to be released in the body to make us try to find food.
It's not the lowering of hunger hormone levels that causes the depression during unmindful fasting. It's the mind's subconscious habit of triggering increase of hunger hormone levels in an attempt to make us try to find food that is the cause of the depression. With mindful fasting the mind is retrained to recognize the fasting periods as the time for starting to eat the damaged and dysfunctional cells in the body.