"If we all lived on grass-fed beef, dry-cured bacon, fresh sustainable fish, nuts, pulses, wholegrain bread, good olive oil, eggs and dairy, more fresh vegetables, less fruit, and no sugar or fast food ever, we would save billions personally and nationally," says Dr Ian White, an intensive care specialist. 

Most of us think we eat a balanced diet. He finds that laughable. "It used to be only the very poor who got fat on a diet of chips and sweet tea. But now we're all eating muesli and flapjacks and ready-meals and sandwiches that claim to be good for us and wondering why we crave more and more. It's because there's hidden sugar or starch in nearly all processed food: soups, pickles, mayonnaise, pasta sauce, soup, fruit yoghurts - sugar or starchy thickeners are added to all of them," he says. "Tobacco deserves punitive taxation because it's bad for us. Sugar is just as bad and costs the nation far more, but I don't see any politicians promising to tax it, do you? If they really want to save the NHS, they could start there."

We're grazing instead of cooking meals. "We eat when we feel like it because food is always available. Hormonally, we cannot cope with this. Our hunger hormones are overridden and our sleep patterns are all wrong so we start to crave more of the same. So people have real difficulty in changing bad habits, followed by depression, followed by weight gain, in a cycle; and they get fatter and fatter and more and more ill and unhappy. Being fat makes them less likely to stay active."

The cost is enormous. "That study which reckoned obesity cost the nation £47 billion a year is probably not far off." Overweight is strongly associated with almost all the top ten drugs prescribed in the NHS. Doctors see a lot of overweight people with self-induced diabetes, back pain, knee pain, depression, malnutrition and even cancers and cirrhosis, largely precipitated by sedentary lifestyles and too much starch and sugar.

If you add the cost of days off work to the cost of ready-meals and fast food, you'd be shocked by how much money we waste. Dr White has written a book about how to change your lifestyle called Get Thinner, Stay Thinner. "If only people could see what I see in intensive care every day," he sighs. "But right now, the British are eating a load of rubbish. More obesity is inevitable."