The Dutch were among the smallest people in Europe 150 years ago and are now among the tallest. Dutch people have said to me that the reason for this is the high-dairy diet they have eaten in the last century.

I wonder if this may be part of the solution, but not all of it. I've noticed when in the Netherlands that the Dutch commonly eat a lunch of brown bread with salami and/or cheese and greens - and wash it down with as much as a pint, not of milk but of a yogurt drink.

I wonder if the tallness and good health is partly due to the good effect on the gut of all those probiotics.

And of course it's Dutch cycling - bicycles are used for nearly half of all home-to-work journeys of up to 7.5 kilometres, and for more than half (55%) of all short journeys to and from school. Half of all journeys are taken by car, a quarter by bike, a fifth on foot and one in twenty by public transport.