Warning People About What Not to Eat in Mexico

The Associated Press calls it a win for anti-obesity activists in Mexico. A decade of fighting about food warning labels has brought a victory. Front of pack labels in Mexico will put big black stop signs on products with too much sugar, salt, or saturated fat. Finally, people will learn what not to eat.

But we have basic questions. How will it affect consumer behavior? Will it actually help reduce the prevalence of obesity?

How Do Health Claims and Warnings Work?

One thing is clear. Health claims can persuade people to eat more. For example, the word is out that almonds are good for you. With a little heart on the front label, Blue Diamond Almonds tell you that they’re “smart eating.” So, almond sales have doubled in the past decade. People are gulping down almond milk like it’s an elixir for immortality.

But don’t seems to be a less potent message. A burger and fries comprise the prototype for an unhealthy meal. Add in a sugary soda and you have a trifecta. Yet burger joints are doing great. Not just the basic McDonald’s. But also more upscale brands – Five Guys, Shake Shack, In-n-Out – enjoy almost cultish popularity. Stupidly expensive burgers are an option, too. Even fake burgers made with pea protein are flying off the grill – despite people knowing they’re not especially good for you.

Why do people eat what they’re not supposed to? First, it tastes good. And second, there’s the phenomenon of reactance. When you tell toddlers don’t, their typical response is defiance. They turn around an do what you told them not to. It turns out that grownups are not so different. Forbidden fruit becomes more attractive.

Mixed Research Findings on Food Labels

Research can give us ammunition to argue both sides of this question. This is often research to prove a point, rather than discover the truth. Activists do studies to show how effective it can be to warn people what not to eat. Food industry groups do research to poke holes in the theory.

Then from the sidelines, observers can say that the food industry is biased, while overlooking the bias of people with a righteous agenda.

For a more even-handed assessment, we refer you to a new paper in the Journal of Food Quality and Preference. Lia Nobrega and colleagues offer experimental evidence that warnings can override promotional claims about a food product’s healthfulness. But they note that these are only relevant for consumers who are ready to compromise on pleasure for health. In addition, they tell us that we need research to assess real world impacts.

So we look at the warning labels in Mexico as a real-world, uncontrolled experiment. Maybe we’ll learn something about telling people what not to eat.

Click here for more on the news from Mexico and here for the paper by Nobrega et al.

Milk for Warmth, WPA poster for the Cleveland Division of Health / Library of Congress

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January 31, 2020