Chips, soda and frozen pizzas tend to be full of salt, sugar and fat, but now scientists are trying to understand if there’s something else about such processed foods that might be bad for us.
Already, the spread of cheap, packaged foods has been linked to rising obesity rates around the world. Yet advice to limit processed foods can seem unhelpful, given how convenient they are and the growing array of products that fall into the category.
While three recent studies offer more clues on how our increasingly industrialised food supply may be affecting our health, they also underscore how difficult nutrition science and advice can be. Here’s what they say.
Cheap packaged foods are everywhere including checkout lines, gas stations and vending machines, and a very small four-week clinical trial might deepen our understanding of why that’s likely fueling obesity rates.
Researchers at the National Institutes of Health found people ate an average of 500 extra calories a day when fed mostly processed foods, compared with when the same people were fed minimally processed foods. That’s even though researchers tried to match the meals for nutrients like fat, fiber and sugar.
The 20 participants were allowed to eat as much or as little as they wanted, and were checked into a clinic so their health and behaviour could be monitored. That’s not all the bad news.
In another study based on questionnaires, researchers in France found people who ate more processed foods were more likely to have heart disease. A similar study in Spain found eating more processed foods was linked to a higher risk of death in general.When fed minimally processed foods, people in the clinical trial produced more of a hormone that suppresses appetite, and less of a hormone that causes hunger. The reason for the biological reaction isn’t clear. Another finding: People ate processed foods faster.
“Those foods tend to be softer and easier to chew and swallow,” said Kevin Hall, a researcher at the National Institutes of Health who led the study.
Another challenge is the broad spectrum of processed foods, and distinguishing which ones might be better or worse as companies continually re-engineer products to make them seem more wholesome. So while the newest studies may give us more reasons to avoid industrialised foods, they also underscore the difficulty of coming up with solutions.