Ultraprocessed foods are associated with a 20% increased risk of depression, as we reported in our last podcast. That’s just an associational finding, but controlled trials have found a large effect size in depression when people switch from the standard western diet – where 50% of calories are derived from ultraprocessed foods – to a Mediterranean style diet that limits them to 2-3 servings a week. We have a patient-friendly guide to that diet in our online journal – look for the May 2019 issue – and in today’s podcast I’ll try to pin down just what an ultraprocessed food is.
The most widely used definition of ultra- also called highly processed foods is the Nova classification, developed in 2009 at the University of São Paulo, Brazil. This classification divides food by how it’s processed – or changed from its natural, raw form – rather than its ingredients. So a raw potato is unprocessed, but what happens if we bake it, boil it, fry it, or add preservatives and turn it into potato chips? That’s what the Nova system is trying to shine a light on. And Nova is not an acronym – it’s named for the star that shines its light.
Minimally processed involves adding salt, oil, sugar, and possibly light preservatives like antioxidants to store or prepare the food. These include canned vegetables, salted nuts, cured or smoked meats, cheese, yogurt, beer, wine, and freshly made bread. So far these are fine without any major health problems.
Then there’s the ultraprocessed foods. These contain chemicals that aren’t typically found in the kitchen, but have been added in to improve the taste, appearance, or sensory qualities of the food. We’re talking about things like food coloring, flavor enhancers, artificial sugars, high fructose corn syrup, casein, lactose, whey, gluten, hydrogenated oils, hydrolysed proteins, emulsifiers and processing aids, soy protein, maltodextrin.
Some sources of ultraprocessed foods are obvious. Fast food, frozen foods, packaged snacks, sodas, ice cream, candy…. But others are less obvious and sometimes masquerade as healthy foods. Margarines, spreads, breakfast cereals, energy bars, flavored yoghurt, instant sauces, baby formula, instant soups, mass-produced packaged breads, distilled spirits like whiskey, vodka and rum and – my favorite term – reconstituted meat products. Those are chicken nuggets, hot dogs, sausages, and burgers.
But what about the packaged foods that claim to be healthy? The Nova system hasn’t taken a stance on specific products, but based on their criteria there are some prepared foods that lean more on the side of processed than ultraprocessed. Those include Dave’s wholegrain bread or sprouted breads like Ezekial, Rx Bars, and Lara bars.
Other supermarket foods that Nova considers minimally processed include dried pastas and rice, whole grain cereals like mueslix varieties, freshly ground peanut butter, oatmeal and grits that aren’t flavored or instant, fresh or pasteurized fruit juices without added sugar, unadulterated home cooked popcorn, dried fruits, beef jerky, pickled foods, canned or smoked meats, breads made without preservatives, cheese, and yes… Bacon.