In a world where many go hungry, most Americans can be thankful that food quantity isn’t our biggest problem. But food quality may be a major concern. Obesity is rising around the world as inexpensive and convenient packaged food options increase. We know that junk food—chips, soda, cookies, frozen pizza, and so on—tend to be full of salt, sugar, and fat. That combo can pack on the pounds. But now scientists are trying to understand if there’s more about processed foods that might be bad for us.
Three recent studies offer clues on how the industrialized food supply affects health. But they also underscore how difficult changing habits can be.
WHAT DOES “PROCESSED” MEAN?
Nearly all foods undergo some processing. Much of it isn’t harmful. But even though processing (milling, freezing, pasteurizing) doesn’t automatically make food unhealthy, “processed foods” is generally a negative term.
Scientists define highly processed foods as those that offer little to no intact food. They contain mostly industrialized ingredients and additives. Sodas, packaged cookies, instant noodles, and chicken nuggets are examples. But some wholesome-sounding products like breakfast cereals, energy bars, and some yogurts also fall into this category.
WHAT’S WRONG WITH PROCESSED FOODS?
Researchers at the National Institutes of Health conducted a study with 20 participants. The test subjects ate as much or as little as they wanted—first from a diet of highly processed foods. Next, they were offered minimally processed foods.
The researchers matched the meals for nutrients and appeal. But still, the same people averaged 500 extra calories a day when choosing among the processed foods.
Elsewhere, researchers in France found people who ate more processed foods were more likely to have heart disease. A study in Spain linked eating more processed foods to a higher risk of death in general.
Why is it so hard to stop eating cheese puffs and ice cream? Two possible factors were identified.
First, when fed minimally processed foods, people in the trial produced more of a hormone that suppresses appetite. They produced less of a hormone that prompts hunger. The reason for the biological reaction isn’t clear.
Second, people ate processed foods faster. “Those foods tend to be softer and easier to chew and swallow,” says study leader Kevin Hall. Eating faster usually means eating more.
IS IT EASY TO CHANGE HOW WE EAT?
Limiting processed foods for a healthful diet makes sense to most people. More natural foods tend to have more nutrients that our bodies need. They’re often harder to overeat because they require more chewing time—and usually a little planning and work. It takes longer to peel an orange than to unwrap a Twinkie or to munch a cup of cucumber slices than a comparable amount of potato chips.
Still, following that advice can be hard for people with limited time and money. Sarah Bowen studies food and inequality at North Carolina State University. She says it’s not enough to simply say, “Change the way you eat.” She says advisors should first understand “why people eat the way they eat.” Then practical suggestions for change can help improve health in sustainable ways.