Grocer (no not her)
I seem to remember that a diet almost exclusively of chickpeas etc damages the nervous system so maybe not suitable commercial weight loss exploitation though I like the idea. I think these side effects of pulses are only seen in the poor who are eating them to excess, if that is not a contradiction.
Regarding old and hard chickpeas needing longer cooking, that applies to all pulses so this is exactly the wrong time of year to find good quality ones. Your grocer (remember them?) is your friend an will be able to tell you how ancient the pulses are that he is selling at any one time.
Curiously, the older peas are more expensive if you are buying them for poultry feed as they lose more and more water each year they are kept and thus have a higher protein content per kilo. Same principle as salami etc.