How does wealth affect your diet?
We have complex reasons for choosing what we eat, and a limited understanding of our motives may be behind decades of unsuccessful and expensive healthy eating policies.
What would you prefer: an Oreo or a cereal bar? What if you were told the healthier option was just as tasty, just as filling, and no more expensive? Your choice might reveal your relative wealth and social status.
We know that poorer people tend to eat more unhealthily than their richer counterparts – but for years we may have misunderstood why. Policymakers have tended to believe that unhealthy diets are a result of healthy options being unaffordable and unavailable, particularly in places labelled "food deserts" and "food swamps". You can find places in parts of the US, for instance, where there is little access to fresh or healthy produce for miles and an oversupply of junk food and other unhealthy options.
But expensive policies in the US that focused on the supply side in these areas, making healthier foods cheaper and more available, have had limited impact. Research has shown that cost and availability are indeed factors in what people eat, but that’s not the full picture.
How we choose what to eat
In a series of experiments, we’ve been able to unpick an extra element that informs people’s choices – and we’ve deduced that this differs among the very rich and the very poor.
There are three key qualities that shape people's food choices: healthiness, taste and how filling it is. It's that last factor that has an outsized impact on people from poorer communities. Nearly nine in 10 people from poorer backgrounds say it’s important, one of our experiments shows, and they feel it’s more important than how healthy a food is.
For these groups, a full stomach is far more important than it is among their richer counterparts. By contrast, the more affluent populations tend to prefer food that is healthy over food that is filling.
Access to healthy foods is critical but it’s only half the battle
Marketing messages from food companies selling unhealthy and ultra-processed foods have long emphasised how their products will fill us up. “Aren’t you hungry?” asked Burger King, while Snickers has used marketing lines such as, “You’re not 'you' when you’re hungry!”.
These preferences might seem logical: the more a food satisfies appetite, the better value for money it appears. People who experience food insecurity will naturally seek food to tide them over and keep hunger at bay. But in our experiments, we’ve shown that, even when cost and supply aren’t an issue, people from poorer backgrounds shun healthy food in favour of what they believe are more filling and tasty options.
Interestingly, while they might differ on preferences for healthy versus filling foods, both rich and poor have one thing in common – no one wants to compromise on taste – it’s just what they perceive to be tasty that differs. People from more disadvantaged backgrounds are more likely to perceive healthy food as bland rather than tasty.
Portion sizes matter
So, what’s going on? Access to filling food appears to be psychologically important for people from disadvantaged backgrounds, beyond the impact of price and availability. And the belief we discovered among poorer people that healthy food is neither filling nor tasty is an effective barrier for the types of healthy eating initiatives we’ve seen over the recent decades.
In the last of our experiments, which we ran in a low-income neighbourhood in Rio de Janeiro, we dug deeper into what might motivate poorer populations to choose healthier and fresher food options.
Is the answer to do as the food industry does and market foods as filling and satisfying, and apply this to healthy fare? Our work shows not: simply telling people that the healthier food option was tasty and filling didn’t really work. People’s beliefs about food are so ingrained, they are hard to tackle, and marketing strategies must be credible. Out of the four different strategies to make healthier food more appealing that we tested, only one seemed to have a positive and clear effect on people’s choices, and it appears linked to portion sizes.
The more a food satisfies appetite, the better value for money it appears
We asked participants to choose between two dishes. Both were the typical Brazilian dish of rice and chicken, but crucially one plate, otherwise identical, was laden with salad, and it’s this that participants chose – perhaps because it appeared fuller despite containing food that we know some consider less tasty and filling.
If policymakers wish to target the kind of nutritional inequality that affects most societies, they need to understand the subtle influences at play. Even today, most policies that try to increase healthy food choices are still overly focused on supply, and yet the results are poor. Access to healthy foods is critical but it’s only half the battle. Does the answer lie in a delicate mix of messages that combine value for money, health, taste and, critically, how filling it is? Could food packaging and marketing be tweaked to convey these messages?
Only by tackling supply and appeal together is it possible to encourage healthier eating across poorer communities.
This article draws on findings from "How Socioeconomic Status Shapes Food Preferences and Perceptions" by Bernardo Andretti (Imperial College London), Yan Vieites (Escola Brasileira de Administração Pública e de Empresas), Larissa Elmor (Escola Brasileira de Administração Pública e de Empresas) and Eduardo B. Andrade (Imperial College London).
