This house believes obesity, and quite possibly most ill-health, is a moral failure. Solving it is a matter of individual responsibility. Proposing the motion is our new health secretary, Andrew Lansley, who said in a speech on Wednesday that what we need is for everyone to be just more responsible.

The captains of the food industry are decent chaps who we will ask to be more responsible and not sell you more sweets, crisps and fizzy drinks than are good for you in exchange for government not regulating their products any further. Individuals should be more responsible about their dietary choices, and that includes schoolchildren, who we will ask to be more responsible about their food since they don't like nannying and hectoring Jamie Oliver-style any more than this health secretary does.

Lansley's analysis of public health is so facile it would be risible even in a prep-school debating society.

He seems even to have forgotten the first rule of arguing your point: research your facts. Figures out yesterday show that, far from putting large numbers off school meals as Lansley had claimed, Jamie Oliver's campaign to improve school meals, and all the government work on nutritional standards that followed, has increased uptake of healthy hot meals at lunchtime. It turns out those in loco parentis, or to use that pernicious rhetoric of the privileged right, "nanny", should decide what's best for children. It works.

Can it be too that Lansley is not aware of all the literature about how individuals' "free choices" are shaped by marketing and advertising. Perhaps we should recommend some urgent remedial reading for his homework, starting with Edward Bernays's essay on Engineering of Consent. Bernays, a nephew of Sigmund Freud, was the first to work out that you could manipulate the public into buying products they did not want or need by targeting their unconscious desires. His first triumphs, in the 1920s, were in the marketing of cigarettes and unhealthy foods. Just like the tobacco industry, the food industry has depended for its sales on this symbiotic relationship with the advertising industry. That's why tackling smoking required "nannying" intervention to control tobacco advertising, to tax cigarette prices up, and to ban smoking in public places to help people quell the desires that had been so skillfully awakened.

Why does Lansley think the food industry has fought tooth and nail to avoid restrictions on its marketing to children? It has to catch them young, to form their palates and create their desires.

Let's add a few basic textbooks to his reading on the nature of business too. What exactly is it Lansley expects the likes of Coca-Cola, Walkers and PepsiCo, Kellogg's, Mars, and Cadbury to take responsibility for? Selling less of their high-salt, high-sugar products? How does that fit with their statutory duty to maximise returns to shareholders?

Which socioeconomic class you are born into is still one of the most significant determinants of how healthy you will be. Diets and diet-related disease are in fact a map of inequality. Those on lower incomes are more likely to suffer obesity, as children and as adults. They have higher rates of raised blood pressure thanks to excess salt in their processed diets. They are more likely to suffer diabetes and heart disease. They have more dental disease from excess sugar.

What's not so much risible but truly frightening about Lansley's speech is that it lays bare the underlying Tory philosophy. In their Big Society – which casts everything as personal responsibility – social injustice, like obesity, is indeed a moral failure, but only on the part of those who suffer it.