Jack Sargeant says: "The Wellcome Trust – Britain's largest and most unique medical archive – has a channel at YouTube where they are posting archival medical films and films about the archive. Titles you can watch include a 1917 documentary on War Neuroses and footage of a Henry Wellcome archeological dig."
From the description for "Cruel Kindness," a 1967 UK educational film about childhood obesity
This extremely enjoyable film, which contains excellent footage of late 1960's home life, attitudes to food and meal times, addresses obesity in children. A female GP narrates the story of three children who are overweight for their age stressing that although there may be some inherited causes of their obesity, it is mostly due to over-feeding on the part of the parents, what the GP calls a cruel kindness.
One interesting thing about this film is that the most of the "obese" children in it look like average kids today.