Network of Stoppages

OW2022: Can We Prevent Obesity?

For decades now, considerable resources have gone toward efforts to prevent the ongoing rise of obesity in the population. But with little success. It keeps on rising. So it seems reasonable to ask, do we have the tools we need for the task of effective obesity prevention?

Professor Lisa Powell provided us with some mixed answers yesterday at OW2022 for one of the go-to strategies in obesity prevention – sugar sweetened beverage (SSB) taxes.

Driving Down Demand

On one hand, Powell told us something that we have heard many times before from advocates for this policy. It has the intended effect. When taxes on SSBs go into effect, the price goes up and demand goes down. There’s some evidence, she said, that people will buy more sweets instead, but it’s too limited to offset the decline in sugar consumption that results from drinking less of the SSBs. In other words, sugar consumption goes down.

An Effect on Obesity and Health? That’s Hard

But then comes the question of an effect on obesity and population health. That’s a tough one. The facts are simple, though. We lack any evidence that the result of implementing these taxes has any effect on health. Not on obesity prevalence, not on diabetes or any other actual measure of health. Bummer.

So the advocates (we count Powell among them) say that we have a lot of work to do. We need broader jurisdictional taxes, she said, because taxing SSBs in one area (like Philadelphia) doesn’t have enough effect if people can just go somewhere else for their soda (like the suburbs). And we need to use the tax revenues to subsidize fruits and vegetables for low-income populations so that this effort to prevent obesity isn’t just a regressive taxation scheme.

Looking for an Effect

But if you want to see an effect of SSB taxes on obesity or any other health outcome, you might wind up looking for a very long time. So long, in fact, that some advocates for obesity prevention suggest that maybe it is simply unfair to expect these policies to demonstrate such an effect. At a recent workshop of the National Academies Roundtable on Obesity Solutions, Harvard’s Jason Block was asked if we should expect obesity prevention policies to have an effect on obesity and he said:

“The short answer is that certainly in the short term, we shouldn’t require that. Over the long term, I think it’s still a debatable question. I think we should attempt to measure it.”

We agree with him on that last point. We should indeed try to measure if our efforts to prevent obesity have an effect. If they do not, then it’s critically important to look harder for new approaches that will actually have an effect.

Obesity prevention is simply too important to accept a continued emphasis on strategies that don’t work.

Click here, here, and here for further perspective.

Network of Stoppages, painting by Marcel Duchamp / WikiArt

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.


November 4, 2022

3 Responses to “OW2022: Can We Prevent Obesity?”

  1. November 05, 2022 at 5:56 pm, virginia erwin said:

    Obesity prevention is like trying to prevent car accidents, the nature of humans is to think it’s not going to happen to them. No matter how much science, funding and technology we throw at obesity prevention we will still have obesity in the population. A similar case can be made to the rise in homelessness. Unhoused people are growing in great numbers all over the country. I believe that some of our modern day health problems stem from multiple changes in our environment, some humans adapt well and some do not. My point is oblique; there is no clear path to go down, after awhile it is just like pulling weeds, and the weeds always come back.

  2. November 11, 2022 at 9:26 pm, Patrick Bradley said:

    Obesity preventive measures are effective.

    Changes in the USA diet demonstrate this.

    Between 1960 and 2000 animal fat consumption declined by 30%. Vegetable oil consumption increased by 100%. Sugar sweetened beverage consumption increased by 150%. Consumption of all caloric sweeteners increased by 30%.

    These changes were associated with an increase in obesity from 10% to 30% and diabetes from 1.5% to 6%.

    Positive changes occurred after that time associated with a decline in per capita sugar consumption from 100 g per day to 76 g per day and a larger percentage decline in sugar sweetened beverage consumption. There were no changes in vegetable oil or animal fat consumption.

    New diagnoses of type 2 diabetes fell by 25% after 2008 and new diagnoses of obesity levelled out between 2006 and 2012 in native born Americans. The incidence of obesity in 2 to 5-year old’s decreased possibly by as much as 20%.

    The time delay between these changes and beneficial changes this is not unprecedented. Deaths from lung cancer did not begin to fall until 20 years after cigarette consumption began to decline.

    • November 12, 2022 at 8:50 am, Ted said:

      Thanks for your thoughts. But a number of facts point to a different story.

      First, despite reductions in sugar, obesity prevalence continues to rise.

      Second, prevalence of diabetes is also rising.
      Diabetes Prevalence Trends
      Third, smoking bans of the 1980s led to rapid drops in smoking, and within a decade, lung cancer deaths began dropping. So the benefits of effective smoking policies did not take decades to appear.