Minimizing your intake of overly processed foods is a significant step towards preventing chronic inflammation and various inflammation-related chronic diseases. However, discerning which foods qualify as “processed” can be tricky, especially considering that some level of processing can be beneficial.
Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, explains, “When done thoughtfully, certain processing techniques can actually enhance the nutritional value or accessibility of foods. This is particularly relevant during seasons when fresh, local produce is scarce. Furthermore, processing can improve food safety, as exemplified by pasteurized milk, which eliminates harmful pathogens. Processes like fermentation can even enhance the health benefits of foods like yogurt.”
So, when does food processing become detrimental, and which processed foods should you actively avoid? Let’s delve into the details.
Understanding Processed Foods
Processed foods are essentially foods that have undergone some form of alteration from their natural state. This could range from simple procedures like chopping and freezing vegetables to removing inedible components, such as nut shells. These minimal alterations are generally considered as light processing.
Next, we encounter processed foods with a few added ingredients. Examples include a simple cracker containing wheat, oil, and salt, freshly baked bread, or canned vegetables preserved in water and salt.
Then there are “ultra-processed” foods, representing a higher degree of processing. Dr. Willett defines ultra-processing as a process that “usually means that the original foods are not recognizable, and they include additives such as preservatives, oil, sugar, salt, coloring, and flavoring. It’s what we mean by junk food.”
Examples of ultra-processed foods are plentiful and include items such as hot dogs and deli meats (more on the dangers below), cheese puffs, doughnuts, frozen pizza, white bread, cookies, microwaveable meals, and sodas.
The Hidden Dangers of Processed Meats
Processed meats rank among the least healthful food choices. Examples include bacon, sausage, ham, hot dogs, salami, and deli meats like roast beef or turkey. These foods are typically high in salt, unhealthy saturated fat, nitrates, nitrites, and a variety of chemical additives, including artificial colors, flavorings, and preservatives.
Processed meats on display at a deli
Alt text: A variety of processed meats including sausages, ham, and salami displayed behind glass at a deli counter.
A high consumption of processed meats has been linked to an increased risk of cardiovascular disease and colorectal cancer. For instance, a 2019 study published in the International Journal of Epidemiology, which involved almost 500,000 participants, revealed that individuals who consumed red or processed meat four or more times per week had a 20% higher risk of developing colorectal cancer over a five-year period compared to those who ate red or processed meat less than twice a week.
The International Agency for Research on Cancer, a division of the World Health Organization, classifies processed meat as a carcinogen (a substance capable of causing cancer) to humans, specifically concerning colorectal cancer.
Understanding the Health Risks of Ultra-Processed Foods
When health experts caution against processed foods, they primarily refer to ultra-processed options. These foods carry several health risks.
Dr. Willett notes, “Processing often diminishes the nutritional content of foods, such as in the refining of whole grains. Furthermore, processing can introduce harmful molecules like trans fat or excessive amounts of detrimental ingredients such as salt and sugar.”
A diet rich in ultra-processed foods is associated with a higher risk of chronic inflammation, various chronic diseases (including heart disease, diabetes, inflammatory bowel disease, obesity, and cancer), and even premature death.
For instance, a 2019 study in The BMJ, involving over 105,000 participants followed for five years, demonstrated that for every 10% increase in the consumption of ultra-processed foods, the risk of heart attack or stroke increased by 12%. Another 2019 BMJ study, this one following nearly 20,000 people for an average of 10 years, found that participants who consumed more than four servings of ultra-processed foods daily had a 62% higher risk of death during the study period (from any cause) compared to those who consumed two servings or less per day.
Identifying Ultra-Processed Foods: What to Look For
Generally, identifying ultra-processed foods is relatively straightforward – they typically have extensive ingredient lists. They are often found on store shelves, in freezers, refrigerated sections, delis, or bakeries. Common categories of ultra-processed foods include packaged, ready-to-eat entrées or meals, prepared side dishes, snacks, and sweets of all kinds (such as cookies and cakes).
However, some ultra-processed foods can deceptively appear healthy. This is especially true for ultra-processed versions of fruit-flavored yogurts, refrigerated soups, refrigerated pastas (like chicken tortellini), granola bars, juices, breakfast cereals, frozen yogurt, low-fat salad dressings, condiments, butter substitutes, low-salt crackers, and nut butters.
Deciphering the Label: Your Key to Identifying Ultra-Processed Foods
So, how do you know if a food is processed to an unhealthy extent? The answer lies in carefully examining the ingredient list on the food label. If you encounter a lengthy list containing numerous ingredients, particularly chemicals or unfamiliar words, the product is likely ultra-processed. In such cases, it’s best to opt for alternatives with shorter, simpler ingredient lists.
Occasional Indulgence: Is It Ever Okay to Cheat?
Avoiding ultra-processed foods entirely can seem challenging, especially when you’re pressed for time or simply craving a convenient treat like a ready-to-eat muffin, a deli sandwich, or a homemade ragù featuring chicken sausage. Is it acceptable to occasionally bend the rules, assuming you generally maintain a healthy diet?
Dr. Willett suggests, “Almost anything is okay if you break the rules just once a month. But keep an eye on the other ingredients. For example, the ragù could be fine if the salt is kept below 200 milligrams [mg] per serving.”
Here are some additional guidelines to consider: Limit your total daily salt intake to below 2,300 mg, unless your doctor recommends a lower amount. Limit saturated fat to no more than 10% of your daily caloric intake. Also, aim to keep added sugars to less than 24 grams per day for women and 36 grams per day for men.
Prioritize incorporating whole, unprocessed foods into your diet as much as possible, focusing on a plant-based approach that emphasizes vegetables, legumes, fruits, whole grains, nuts, and seeds.
Finally, remember that “Just because foods are unprocessed, it does not mean that they’re healthy,” Dr. Willett emphasizes. “A diet based on red meat, milk, and potatoes is unprocessed but far from optimal.”
