A few years ago, a common sight on English door-steps was that of garden birds pecking through the tin foil tops of milk bottles. It no longer is - for the milk in the bottles no longer contains a top layer of cream. This is mainly because most families have moved to semi-skimmed or even skimmed milk, low in cream.
There have been other changes. On the table you may find cream and butter substitutes. One popular butter substitute is made from olive oil, another from pine tree oil. As we have frequently reported, olive oil and similar vegetable oils are the height of healthy eating. Farm products - milk, butter, cheese, cream, meat and eggs - are regarded with suspicion or as occasionally luxuries or treats, even though they have been a staple part of human diet for thousands of years.
In the 1970s the withdrawal of free school milk from schools was a big issue. When free food was returned to schools in the 1990s, it was fruit, not milk.
Now a remarkable study in the journal Heart suggests this view may be flawed. The evidence is powerful because it has been collected over 70 years and is based on a pioneering study of British eating habits. Researchers set out to relate the fate of the people in the study to their childhood eating habits - which had been well documented. The findings show no evidence that children who were stuffed with full-cream milk products had unhealthy hearts or circulation. And in fact they had the lowest death rates of any of their generation - and also enjoyed low death rates from stroke.
And the chances are that these children enjoyed a full cream diet. In the 1930s, if you could afford it, you could have a full cream pudding on your table every day - notably blancmange and rice pudding. There was also sago pudding, tapioca pudding, ground rice pudding.
Now, of course, this study does not compare the 1930s diet with a more modern diet. But it does chronicle a generation of Britons that has lived for longer and more healthily than ever before. It may be that those brought up on semi-skimmed milk and olive oil butter substitutes will do even better.
So for this 1930s generation, a childhood rich in full cream did no harm. One possibility is that it also had a big impact on the health of the bones - rendering dairy eaters less prone to bone breakages, falls and orthopaedic operations. That might explain their reduced death rates.
The big question about the research is whether dairy products were the only healthy factor in the children's diets. Maybe they consumed more milk and cheese because their families were wealthier than others. Perhaps a healthy level of calcium in the diet was an indication of a proper diet - as opposed to the restricted diet that poorer families might have lived on in the turbulent 1930s.
The detailed breakdown of the findings tends to bear this out. About 25 per cent of the children ate at least twice as many dairy products as others. These tended to come from high status social groups and to be taller and better fed than other children, getting about 20 per cent more energy than others in their daily diet. However they did not necessarily eat as many vegetables or as much fat as other children.
So although it is true that the high calcium levels in the children's diets probably reflected their families' greater wealth than others, it does not disprove the benefits of calcium and milk products. For, if wealth leads to better health, there must be a way this is achieved. And it is the high intake of dairy products - of all those milk puddings, rather than of fruit and vegetables - that stands out as a key feature of these 1930s families.
The researchers write: "Dairy products are important contributors to children’s intake of protein, vitamins and minerals and they play an important role in the maintenance of bone health.
"The beneficial effects of dairy and calcium intake suggested by this study were seen at estimated intake levels that are similar to the currently recommended intake amount for dairy and calcium in children."
More reports on diet and health here.