We never seemed to suffer from constipation pfr. My father had an allotment and we ate positively tons of fresh veg, apples, rhubarb and so on.
Porridge too - lots and lots of roughage. I actually believe post-war families were better fed than many folk today.

My husband was suffering from calcium deficiency when he arrived in UK. His bones were like sponges, poor man, and he had rickets from lack of vitamin D. They had very little in their diet, and never got within sniffing distance of any milk. I fed him as much nourishing food as he could stomach, plus vitamin supplements, and he actually grew about 5 centimetres in a year, due to his vertebrae gaining in density.

This spare milk from the 'lake' could be well-used in developing countries, in powder form. I'm sure the main charities such as Oxfam would be glad of it.