How do women from Impoverished Nations Produce Breastmilk?

So, I am supposed to be eating lots of fish and drinking lots of fluids etc.....eat healthy, eat alot.....and I should be able to produce a lot of milk.

How do women from tribes in FAR OUT AREAS - you know where there is only dust and 3 goats and people have to scavenge for roots for water - how do those women produce breastmilk? When I get on Wikipedia and check out Breastfeeding, I see pictures of these women with their full breasts, purportedly breastfeeding - how do they do it?