Why were people thinner in the 1970s?

from Boing Boing:

On July 26, Guardian columnist George Monbiot tweeted a photo of people on Brighton Beach in 1976, with the comment:

In this photo, from 1976, almost everyone is what we would now call slim. So what has happened? A sudden loss of willpower, as some rightwing journos claim? No. An obesogenic environment created by junk food manufacturers and their advertisers.

As you can see, lively Twitter discussion ensued. Monbiot did some research into people's dietary and exercise habits, then and now. He found that people actually ate more in the 1970s than they do now. Manual laborers are heavier today than they were in the 1970s. Kids move around as much today as they did 50 years ago.

"So what has happened?" asks Monbiot? His answer: lots more sugar.

The light begins to dawn when you look at the nutrition figures in more detail. Yes, we ate more in 1976, but differently. Today, we buy half as much fresh milk per person, but five times more yoghurt, three times more ice cream and – wait for it – 39 times as many dairy desserts. We buy half as many eggs as in 1976, but a third more breakfast cereals and twice the cereal snacks; half the total potatoes, but three times the crisps. While our direct purchases of sugar have sharply declined, the sugar we consume in drinks and confectionery is likely to have rocketed (there are purchase numbers only from 1992, at which point they were rising rapidly. Perhaps, as we consumed just 9kcal a day in the form of drinks in 1976, no one thought the numbers were worth collecting.) In other words, the opportunities to load our food with sugar have boomed. As some experts have long proposed, this seems to be the issue.

The shift has not happened by accident. As Jacques Peretti argued in his film The Men Who Made Us Fat, food companies have invested heavily in designing products that use sugar to bypass our natural appetite control mechanisms, and in packaging and promoting these products to break down what remains of our defences, including through the use of subliminal scents. They employ an army of food scientists and psychologists to trick us into eating more than we need, while their advertisers use the latest findings in neuroscience to overcome our resistance.