Believe it or not, people actually like smoking and eating fatty food

Public information campaigns and nutritional labelling are good at informing people about what’s healthy and what isn’t, but don’t seem to have much impact on what they actually eat. That’s what a comprehensive review of 121 'healthy eating' policies found, and I think it should make us rethink more heavy-handed policies to do with unhealthy food, tobacco and alcohol. There are benefits as well as costs to every activity that public health groups want to discourage. We know there are benefits because people do them freely. But we know there are costs as well, like living a shorter and less healthy life.

The liberal view is that each person’s cost-benefit calculation is different, because they enjoy and dislike things differently. In this view there’s no case for stopping people from doing things unless they don’t actually have the information they need to make a judgement. We should want to make people’s lives better as they themselves understand ‘better’, not according to a single measure we’ve decided on, like lifespan.

So telling people that sugar makes them fatter may be a good policy, if they didn't already know that. And policies that do that do seem to make people more informed. But what’s interesting is the impact they have on people’s diets – usually not much, and sometimes an unexpected one.

For example, a 2008 study found that people who used nutrition labels had big increases in fiber and iron intake, but no change to their total fat, saturated fat or cholesterol intake. The UK’s ‘five a day’ campaign about fruit and veg was very successful at getting people to think about eating more fruit and veg, but increased people’s intake by an average of 0.3 portions a day (which was not viewed as being a very good improvement). 44 studies of similar campaigns in the US and EU have shown about the same size effect.

To some people that might make it look like we need to do more. To me it looks as if people view the costs of changing their diet to something less enjoyable or convenient as being quite important, and are willing to forgo some level of health to avoid that.

Maybe this tells us something about cigarette regulation too – there is some evidence that smokers actually overestimate the risk of smoking and some that they underestimate it. If they do overestimate the risks, we’re ‘informing’ people so much that it’s become misleading.

It would be fair to respond to this that people have no real way of doing a proper cost-benefit analysis about eating sugary foods or smoking, but because the state can’t measure the benefits – that is, the pleasure – it is just as limited.

The fact that people do change their habits about iron and fibre, but not fats, suggests that they aren’t ignorant, they just don’t want to eat less fat! If that’s the case and we’re working to improve people’s lives on their terms, there is no case at all for more heavy-handed policies like taxes, ingredients restrictions and advertising bans.

Enemy of the steak: what's wrong with government diet guidelines

As an amateur chef I have become increasingly interested in the government’s guidelines and regulations around food. For something so central to our lives, the advice and rules the government makes to do with what we eat are usually overlooked. Two developments this week suggest that this is a mistake. I have previously argued that government regulation is often bad because, if it turns out to be bad regulation, it imposes a single error across an entire group of people or firms. That view may explain the financial crisis, where banks were required to hold lots of mortgage debt by regulators who thought they were forcing banks to be sensible.

Now, it looks as if it might also apply to diet guidelines. This week a new paper has been published that argues quite convincingly that, not only does modern evidence show that government guidelines to reduce dietary fat intake were a bad idea, they were even against the bulk of the evidence available at the time.

Today, it’s being reported that the US will stop advising people to avoid dietary cholesterol, because of a change in nutritionists’ view of how our diet affects our bodily cholesterol levels.

The Verge says that ‘The DGAC is more concerned about the chronic under-consumption of good nutrients, noting that Vitamin D, Vitamin E, potassium, calcium, and fiber are under-consumed across the entire US population.’ Interestingly, high-cholesterol foods like eggs, offal and seafood are very high in some of those vitamins.

It’s tempting to suggest a connection there – that vitamin deficiencies may be a direct cause of misguided government diet advice. And this may be the case. But, having looked around and spoken to the British Nutrition Foundation, I can’t find any work by either the government or independent academics on how much impact these guidelines have on what we eat, let alone on our health. (The exception is the five-a-day campaign, which has been fairly successful.)

If it turns out that diet guidelines have been wrong on things like fat and cholesterol, and maybe things like salt as well, what are the costs? I see there being two potential downsides to bad advice. The first is that the advice is actually dead wrong and drives people to eat in ways that ends up being worse for their health. Perhaps this is true of the cholesterol advice.

The second, which is more ambiguous, is the welfare cost. We eat not just for sustenance but because it gives us pleasure – a steak done well is much better for me than a well-done steak, because, even though the nutritional content is basically the same, it makes me happier. If government guidelines have been mistakenly putting people off eating foods they enjoy then they have been costly in welfare terms even if the health impact is not significant.

Of course people may need to get advice from somewhere, and I don’t see any reason to believe that government advice is worse than, say, the stuff you get in the Femail section of the Mail Online website. But if government diet regulations are still likely to be mistaken, and they influence people much more than any single bit of diet advice from an independent source, then they may end up holding back a process of private trial and error that would give us better information about what’s good to eat over time.