People are going to have very strong opinions about this post, so let me head that off on the front end by telling you the genesis of this (admittedly lengthier) post. I was doing a course over at the Daily Dad called The Daily Dad Parenting Challenge, and one of the “challenges” was to get in-sync with your spouse. The topics were were pretty vast, but one stood out in particular: nutrition.
We all have opinions about nutrition, and I would be willing to bet those opinions can be pretty strong. Well, our household is no different and, in the process of hashing it out, my wife asked, “Just how bad are processed foods, anyway?” I’m pretty well-read in the area of nutrition, but this specific question caught me off-guard and, frankly, flat-footed. My answer—which might also be your answer—was I don’t know.
Sure, we might refer to these products as junk food and know inherently that they aren’t good for us, but we really don’t even know that for sure. So I did the exact opposite of what most reasonable people do—which is to move onto something fun—and instead put on my best
hat, hit the research, and wrote my wife a research paper that is now this blog post.So, what did I find? Well, for that you’ll have to read on…
Let’s Get Started - Introduction
Processed food is any food that’s altered during preparation. Some foods are much more processed than others. A bagged salad or cut green bean is technically processed, but it’s only minimally processed because its natural state hasn’t changed. In other words, it looks pretty much the same as you’d find it in nature. A box of macaroni and cheese or a microwavable dinner, on the other hand, are considered heavily processed (also called ultra-processed) because they’ve been chemically altered with artificial flavors, additives, and other ingredients.
Most foods we eat have been processed in some way by the time they reach our plates. However, the concern about processed food isn’t over items like canned tomatoes or canned tuna, which are processed to lock in freshness and nutrients. The concern is over more heavily processed foods like crackers, jarred pasta sauces, and cake mixes. And we eat a lot of these foods – the U.S. National Health and Nutrition Examination Survey released an estimate that roughly 60% of the calories in the average American diet come from ultra-processed foods. Further, Harvard data estimates that ultra-processed foods contribute about 90% of the total calories obtained from added sugars.[1]
Health Impacts
Identifying a strong causal link between ultra-processed foods and health is difficult because (1) ultra-processed foods are relatively new and (2) there are ethical concerns with designing randomized, double-blind studies with ultra-processed foods hypothesized to cause major physical ailments like cancer (…hey, half of you go do this thing we think causes cancer and then we’ll see if you get cancer … that’s not gonna fly!).
That said, there is strong reason to believe that ultra-processed foods have a negative impact on health. One study from the National Library of Medicine reviewed 43 studies and found that 37 of them (or 86%) found dietary ultra-processed diet exposure associated with at least one adverse health outcome. For adults, these outcomes included overweight, obesity, cardio-metabolic risks, cancer, type-2 diabetes, cardiovascular disease, irritable bowel syndrome, depression, frailty, and all-cause mortality. For children and adolescents, these outcomes included cardio-metabolic risks and asthma. Notably, no study reported an association between ultra-processed foods and beneficial health outcomes.[2]
In a different review of 20 studies (12 cohort and 8 cross-sectional studies), ultra-processed food was associated with an increased risk of all-cause mortality, overall cardiovascular diseases, coronary heart diseases, cerebrovascular diseases, hypertension, metabolic syndrome, overweight and obesity, depression, irritable bowel syndrome, overall cancer, postmenopausal breast cancer, gestational obesity, adolescent asthma and wheezing, and frailty.[3] Notably, these studies had a total of 334,114 participants - not bad!
Knowing this information still isn’t enough to make an informed decision about ultra-processed foods, though, because we still need to gauge how bad. Bad like smoking? Bad like working in a coal mine? Bad like that time you skipped school? How bad?
Well, one of the best studies out there, published in the British Medical Association’s peer reviewed journal—the BMJ—comes from France. Surprise, the study found that every 10% increase in consumption of ultra-processed foods was associated with a 12% higher risk for cancer in general and an 11% increased risk for breast cancer.[4] The study also identified associations between ultra-processed foods and cardiovascular disease, coronary heart disease, and cerebrovascular disorders.
While the study’s methodology wasn’t perfect, it was still pretty good. Specifically, the study analyzed dietary questionnaire answers of 105,000 middle-aged men and women in France for five years. Foods were grouped according to degree of processing — that is, the amount of change the ingredients go through as food makers improve flavor, coloring, and shelf life. For example, dehydrated soups, baked goods, sugary cereals, processed meats, biscuits, and sauces were considered ultra-processed foods. Less processed foods included canned vegetables, cheeses, and freshly made unpackaged bread.
This study isn’t alone. Another study published in the BMJ out of Spain found that each additional serving of ultra-processed food was associated with an increase in the all-cause mortality risk by 18%.[5] This study involved roughly 20,000 adults ages 20-91 from 1999-2014. The study also found that eating more than four daily servings of ultra-processed foods was tied to a 62% higher risk of premature death compared to eating little or none of these foods and noted that every 10 percentage-point increase in the share of the diet made up of ultra-processed foods was associated with a more than a 10% increased risk of cardiovascular diseases.
Basically, nutrition researchers worldwide have increasingly implicated ultra-processed foods with poor dietary quality, and with adverse metabolic and health outcomes across a range of populations and in a variety of country contexts. These studies found these effects even when all lifestyle factors were accounted for.
Unfortunately, I think there are reasons why the health impacts of ultra-processed foods would be even worse in the United States. While I am not able to say with any degree of confidence how much worse I think they would be, I am able to articulate why I feel this way: the Food and Drug Administration (FDA).
The EU (which applies to Spain and France, referenced in the previous studies) takes a more precautionary approach to chemical additives and pesticides than the FDA, which weighs the risks of chemical additives and pesticides from the standpoint of probability of an adverse outcomes instead of possibility of an adverse outcome. Couple this key philosophical difference with an extremely powerful and well-resourced food lobby in the US, and this dramatically changes the nutritional landscape between the US and the EU.
Here are just some (seriously - emphasis on some) of the examples of the things allowed in the US but banned in the EU:
Chicken Washed in Chlorine - Chicken produced in the United States gets washed in chlorine to reduce its risk of spreading diseases and illnesses like salmonella. This practice is banned in the United Kingdom and the European Union.
Titanium Dioxide - Found in Skittles, Starburst, baked goods, soups, broths, sauces, and sandwich spreads, this chemical has been shown to be genotoxic in studies, meaning it has the ability to damage DNA and may lead to carcinogenic, or cancerous, effects.
Potassium Bromate - Used in white flour, bread, and rolls to increase the volume, this additive has been shown to cause cancer in animals and has been banned in most countries.
Azodicarbonamide - Found in bread and packaged baked goods, this additive is also used to make plastic for sneakers and yoga mats. This creates a recognized carcinogen when baked.
BHA and BHT – Food preservative, reasonably anticipated to be a carcinogen according to the US Department of Health and Human Services.
Color Dyes (Yellow No. 5, No. 6, Red No. 40) – Synthetic dye, the American Academy of Pediatrics advised that existing research raises concerns about these dyes and their role in child behavior and exacerbating attention deficit hyperactivity disorder.
Brominated Vegetable Oil (BVO) – An emulsifier previously found in Mountain Dew and Gatorade, this additive can build up in the body and potentially lead to memory loss as well as skin and nerve problems. BVO is a flame retardant.
America’s choice of commerce over public health likely indicates that the health consequences of ultra-processed foods found in the France and Spain studies would be exacerbated to some extent in the United States, where regulations over what can pesticides and additives can be used to produce food are more lax. For example, this picture showcases the difference between what’s allowed in McDonald’s fries in the United States vs. the United Kingdom:
Before I wrap all this up, I want to make three points. First, the purpose of this post is not to tell you what to do - it is to empower you with the information you need to make the right choices for you with your preferences and your life’s constraints! Sure, ultra-processed foods are crap, but they are also convenient, shelf-stable, and cheap. That’s still something!
Second, it is still important to put this data into perspective. Eating processed foods is light years better than smoking, which makes it 15 to 30 times more likely that you’ll get or die from lung cancer, and that link IS causal.
Last, I get that this post is not ending with a flood of optimism. While you might have started this post unsure about how bad junk food was for your health, you’re ending it unsure how to make meaningful change besides maybe some newfound dedication to ordering your cheese steaks with real cheese instead of cheese whizz. Or maybe not.
Regardless, I promise I’ll address that topic in a later post (I’m thinking football season = bad and New Years = good for that one 😁). For now, let’s finish this out with today’s highlight reel and get you on your way.
Today’s Highlight Reel
We’ve covered a lot today, so let’s round this out with the highlights:
Ultra-processed foods do not definitively cause cancer; however, ultra-processed foods were not introduced into the food system until modern times and ethical concerns prevent researchers from designing randomized, double-blind studies, which creates research challenges.
Nearly every study of ultra-processed foods has shown an association with at least one adverse health outcome. Virtually all of the obesity and type 2 diabetes, 80 percent of the cardiovascular disease, and more than a third of all cancers can be linked to the Standard American Diet (SAD). Four of the top ten killers in America are chronic diseases linked to this diet.[7]
In contrast, populations eating a remarkably wide range of traditional diets generally don’t suffer from these chronic diseases. Traditional diets run the gamut from ones very high in fat (the Inuit in Greenland are an example which subsists largely on seal blubber) to ones high in carbohydrate (example: Central Indians have a diet largely made up of maize and beans) to the ones high in protein (the Masai tribe in Africa live off cattle blood, meat, and milk).[8]
For context, smoking cigarettes is light-years worse than ultra-processed foods. People who smoke are 15 to 30 times more likely to get lung cancer or die from lung cancer than people who do not smoke. Smoking, however, does have parallels with the food industry. People have smoked for thousands of years using one ingredient: tobacco. Today, commercial interests have changed how cigarettes are created and marketed. There are now 599 known additives in cigarettes.
Some of you might still be wondering where my wife and I ended up landing on this issue. Good memory! We settled on limiting ultra-processed foods as much as possible without sacrificing our relationships or being huge weirdos. A very science-y stance, right? Frankly, I recognize it’ll be awhile before our culture catches up with the science, and there, too, the research is clear: having the right relationships matters more than having the right food. Keep it all in perspective!
Until next time,
-Tully-
[1] https://www.hsph.harvard.edu/nutritionsource/processed-foods/
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399967/
[3] https://nutritionj.biomedcentral.com/articles/10.1186/s12937-020-00604-1
[4] https://www.bmj.com/content/365/bmj.l1451
[5] https://www.bmj.com/content/365/bmj.l1949
[6] https://www.lhsfna.org/the-many-health-risks-of-processed-foods/
[7] Michael Pollen – Food Rules
[8] Id.