Technically, many of the healthy foods we eat are processed, but not in the way you might think. It's a matter of semantics. For example, if you have a Mason jar full of organic dried beans, you have processed food in your pantry. Frozen vegetables are processed, even if you picked the vegetables from your garden, blanched them and put them in the freezer. The moment you blanched them, you processed them. Peanuts-only peanut butter, steel cut oats and organic extra virgin olive oil are all processed to a degree, yet most people consider these foods part of a healthy diet.
When we say we shouldn't eat processed foods, what we really mean is ultra-processed foods. There's a difference, and studies say Americans are eating way more ultra-processed foods than we should, leading to excessive (and often unrealized) sugar consumption with some unfortunate health consequences.
What are ultra-processed foods?
Ultra-processed foods, according to a 2016 study published in the medical journal BMJ Open, are "industrial formulations which, besides salt, sugar, oils and fats, include substances not used in culinary preparations, in particular additives used to imitate sensorial qualities of minimally processed foods and their culinary preparations."
Let's take a practical look at what that means. I keep whole-grain naan flatbread in my freezer because it rounds out quick, healthy meals.
If I made naan at home, I would make it with ingredients like flour, yeast, milk, butter and salt. But I normally buy naan from the grocery store, and while the brand I buy contains almost the same ingredients as a homemade version, it also includes the additive dextrose, a type of sugar. It's a trade-off that's worthwhile for me, but it's one that I'm aware of — and that's an important point.
Sugar in processed vs. ultra-processed foods
Researchers found those who eat a diet that's heavy in ultra-processed foods are getting a lot of added preservatives in their diet in addition to an overabundance of sugar. In ultra-processed foods, sugar makes up 21.1% of the calories, on average. In processed foods, sugar makes up only 2.4% of the calories, on average. Keep in mind that the USDA dietary guidelines say sugar should make up only 10% of your daily calories.
If we ate ultra-processed foods only occasionally, it wouldn't be as big of a problem. However, researchers found that almost 58% of the calories Americans consume are from ultra-processed foods.
If you're eating an average American diet, chances are you're eating too many ultra-processed foods and those foods are adding more sugar to your diet than you would expect. You don't expect, for instance, that a frozen lasagna will contain two teaspoons of sugar per serving. Neither would you expect that a snack-pack portion of applesauce contains six teaspoons of sugar when homemade applesauce doesn't need any added sugars to be sweet and delicious.
If you're looking to decrease the sugar in your diet, decreasing the ultra-processed foods you eat, even the ones that you wouldn't normally associate with sugar, can help you achieve your goal.
In a recent study conducted in France, researchers found that people who increased their daily intake of ultra-processed food by 10% faced a 14% higher risk of early death. For the research, 44,551 French adults aged 45 and older offered information on their diet, health and physical activity for two years. Ultra-processed foods accounted for about 14% of the weight of total food consumed and about 29% of total calorie intake.
Ultra-processed food consumption was associated with younger age, lower income, lower education level, living alone, higher body mass index and lower activity level. The study was published in JAMA Internal Medicine.
The same authors published a 2018 study that found people who increased their daily intake of ultra-processed food by 10% increased their risk of developing overall cancer by 12% and breast cancer by 11%. While the study didn't identify the exact reason why ultra-processed foods causes a higher risk of cancer, researchers did have several theories.
One theory is that the foods contain high levels of salt, sugar and fat. Those ingredients have been linked to obesity, which can also lead to a greater risk of cancer. A second theory is that some ultra-processed foods contain certain additives that have carcinogenic properties. For instance, titanium dioxide is used as a whitening agent or in food packaging to improve food's texture. Studies have shown that the additive could cause lesions on the colon or gastrointestinal inflammation.
Also, another theory is high temperatures used to process the food can create newly formed contaminants. Finally, BPA (Bisphenol A) is commonly used in food packaging and can leech into the food.
Interestingly, a 2019 study conducted by researchers at the National Institutes of Health, found that eating a diet made up of ultra-processed foods prompts people to overeat and thereby gain weight. Researchers found that volunteers on an ultra-processed diet ate about 508 more calories each day and ended up gaining an average of two pounds in two weeks. Study participants who ate whole or minimally processed foods lost about two pounds during that same period.
While further studies are needed to know the exact reasons why ultra-processed foods can have such an impact on health, it's safe to say that the consequences of eating them outweigh the benefits.
Editor's note: This file has been updated since it was originally published in March 2016.