There is both a certain hysteria about us all being fatty lardbuckets and also a true outbreak of us all being fatty lardbuckets at present. The obvious question is why? For only once we know why this is true can we attempt to do something about it.

Various bits and pieces of thinking are put forward. It must be because food is cheap therefore we're all eating more. Or our grotesque modern consumption of sugar. Or fizzy drinks, or, well, something! That we eat fewer calories than our forefathers, less sugar than in the past, means that those three explanations can't really be true even given their popularity within political circles.

As we've been muttering for some time now we think it is ubiquitous central heating:

Opening your bedroom window at night to allow in a cool breeze could be simple, if chilly, way of preventing obesity and Type 2 diabetes, an Oxford University academic has suggested.

Professor of Endocrinology Ashley Grossman said there was mounting evidence that cooling the body even by just a couple of degrees was beneficial for health.

Of course there's some burble about climate change in this report just to be fashionable but still:

A recent study by Maastricht University Medical Centre in the Netherlands advised turning the thermostat down to between 15 C and 17 C for a few hours a day to keep weight down.

The experts claimed that because we spend so much time indoors, often in overheated homes and offices, our bodies do not naturally burn calories to keep warm. Temperatures closer to what it is like outside might be more beneficial to health.

Simply being colder raises the metabolic rate - the speed at which calories are burnt - by 30 per cent,

We base out thinking on the point that the major energy usage in a mammal is body temperature regulation. Now that we've automated much of that the imbalance between calories in and out has widen - thus we all get fat.

Now that we've identified the correct cause we can design a solution. The most obvious would be to plunge the entire population into fuel poverty so that we have to cool our homes. Fortunately we have government departments working on that already what with those green energy plans so we're sorted, aren't we?