Obesity Solution: Don’t Let Them Eat Cake

“The evidence is stacking up,” say Susan Jebb and Theresa Marteau. Sugary drink taxes have been so successful in the UK that the time has come to move on and tax chocolates, biscuits, and cake. And they have a modeling study to prove it. In just one year, a 20 percent tax on sugary snacks will reduce the prevalence of obesity by 2.7 percentage points. AMAZING.

Nothing yet has ever had a measurable effect on obesity prevalence. But Jebb and Marteau say this will do it. It might be a little unpopular at first, but popularity will grow when people realize how much healthier they’ve become. “Hypothecation” also helps increase public acceptance, they say. That means promising to spend the money on children’s health.

A Model Tool for Persuasion

Pauline Scheelbeek is the lead author on the modeling study used to support this idea. Jebb and Marteau are co-authors. They estimated the impact of the 20 percent tax on household purchases. They found it worked great and in a very targeted way. The biggest effect was upon what they called “obese households.” High income households with no overweight felt the least effects.

A cynical observer might view this as an strategy for taxing the fat and poor. But for people with their hands on the levers of power, it might sound great.

A Static Model for Weight Loss

This model is a bit opaque. We can find few details to suggest that the modelers think people might consume more of other things when taxes hit their tea cakes. But they surely will. And food makers will be there to meet the demand for those other things. This is because we know that obesity is driven by complex, adaptive systems. Push in one place and the systems push back in another.

Another issue is how they modeled this fantastic weight loss:

We used a static model for weight loss based on changes in energy consumption, which might not fully reflect actual mechanisms of weight change.

That is a brilliant understatement. To their credit, the authors concede that it’s a weakness in their study. And indeed it is. A static model for weight loss says, for example, that if you cut 3,500 calories from your diet (500/day), you will lose a pound a week. This false assumption just won’t die. Perhaps Scheelbeek et al used a different static assumption. No matter.

Any static assumption for weight loss is bound to be false. That’s because bodies adapt to protect their fat mass. It’s essential for survival.

Don’t Let Them Eat Cake

Hiking the price of cake or chocolate or biscuits is unlikely to reduce the prevalence of obesity. People can find alternatives for caloric pleasure. However, just as Denmark’s Fat Tax was massively unpopular, this tax would surely be unpopular, too.

Let them eat cake (or brioche) was not a very good answer for hunger. “Don’t let them eat cake” is unlikely to be a robust obesity solution.

Click here for the modeling study and then here, here, and here for more enthusiastic views of it.

Brioche, photograph © Maritè Toledo / flickr

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September 8, 2019

4 Responses to “Obesity Solution: Don’t Let Them Eat Cake”

  1. September 08, 2019 at 9:06 am, Mary-Jo said:

    Modeling studies are great, but the “model outcomes should be regarded as estimates on the order of scale of any such price increase strategy and would, as with any modelling study, require further “real life experience” testing to further quantify the effects on health.”

  2. September 08, 2019 at 9:10 am, David Brown said:

    From the article: “Nothing yet has ever had a measurable effect on obesity prevalence.”

    That’s because all of the current strategies for attacking the problem treat the symptom but don’t address the cause which has to do with the essential fatty acid profile of the food supply. Here is some commentary that explains where the problems lie.

    Excerpt: “This risk of developing obesity and T2D has largely been blamed on the increased consumption of energy dense foods and fat intake, particularly saturated fat, but it is interesting to know that the mean fat intake of the human population has not increased much in the past 50 years.It is true that the vast advancement in technological developments has led to a reduction in physical activity worldwide, but as obesity now involves infants and the populations of developing countries, this obesity pandemic cannot be attributed to this alone.In addition, laboratory and other domesticated animals have also been subject to the increased prevalence of obesity, despite having largely unchanged living conditions for many years.

    Excerpt: “Even though the underlying biochemical mechanisms have been thoroughly studied for more than 30 years, neither the agricultural sector nor medical practitioners have shown much interest in making practical use of the abundant high-quality research data now available… It is shown how an unnaturally high omega-6/omega-3 fatty acid concentration ratio in meat, offal and eggs (because the omega-6/omega-3 ratio of the animal diet is unnaturally high) directly leads to exacerbation of pain conditions, cardiovascular disease and probably most cancers. It should be technologically easy and fairly inexpensive to produce poultry and pork meat with much more long-chain omega-3 fatty acids and less arachidonic acid than now, at the same time as they could also have a similar selenium concentration as is common in marine fish. The health economic benefits of such products for society as a whole must be expected vastly to outweigh the direct costs for the farming sector.

  3. September 10, 2019 at 1:56 pm, Alice Mecklenburg said:

    Politicians see a ‘fat tax’ or ‘sugar tax’ as a win-win — claw back money from disproportionately low-income families and reduce obesity at the same time.

    As you rightly point out, there is much more nuance to this than policymakers realize and I fear that confirmation bias drives bad decisions.

    We already know taxes of this nature disproportionately affect homes that are below average-income — but again, even if we pick and choose which foods are affected by the tax, there will always be other cheap, calorie-dense options available.

    I also can’t help but be amused by the fact that we’re still having to debunk the myth that 3,500 calories = 1 pound of weight loss per week. A fat tax is a lazy solution to a complex problem and we need a much defter touch if we’re going to solve it.

    • September 10, 2019 at 7:13 pm, Ted said:

      Amen, Alice.