Two studies show that the more processed foods you eat, the more likely you are to suffer a heart attack or colon cancer:
• Researchers followed 3,000 middle-aged people, average age 53, for 18 years and found out that the more ultra-processed foods they ate, the more likely they were to suffer a heart attack. Each daily serving of ultra-processed food increased heart attack risk by seven percent, and increased risk of death from a heart attack by nine percent (J Am Coll Cardiol, Mar 2021;77(12):1520–1531). They found that heart attacks were associated specifically with eating processed meats, bread, salty snack foods, and soft drinks. Other studies have shown similar results (BMJ, 2019;365).
• Researchers in Spain followed nearly 8000 people and found that taking ultra-processed foods and drinks is associated with increased risk for colorectal cancer (Clinical Nutrition, April 1, 2021;40(4):1537-1545). A 10 percent increase in ultra-processed foods and drinks was associated with an 11 percent increase in the risk of developing colorectal cancer. Several other studies have shown similar results (BMJ, May 29, 2019;365;l1949; Am J Clin Nutr, 2009;89:1441-1452). Processed foods are usually low in fiber, which may help to prevent colon cancer. Processed foods can also contain some additives that are known carcinogens.
Definitions of Processed Foods
Ultra-processed foods are “Formulations of several ingredients which, besides salt, sugar, oils, and fats, include flavors, colors, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods, or to disguise undesirable qualities of the final product” (BMJ Open, March 9, 2016;6(3)). Ultra-processed foods include soft drinks, most dry breakfast cereals, frozen pizzas, frozen meals and entrees, most supermarket breads, cakes, pies, cookies, snack bars including sports nutrition bars, diet bars and “energy” bars, candy, crackers, salty snack foods such as potato chips, corn chips and pretzels, processed meats including those made from poultry or seafood, instant soups and noodle bowls, bottled juices, salad dressings and many others.
Minimally-processed foods are parts of plants or animals that have been factory-cleaned and packaged and may have been ground, chopped or otherwise reduced to small particles; blanched or pre-cooked; and/or frozen, canned or dried. Non-flavored dairy products including cheeses and plain yogurt, and simple prepared foods such as pastas or whole grain bread can also be considered to be minimally processed. If the package has a very short list of ingredients (1-4), the food is probably minimally processed, but check for added sugars.
Unprocessed foods are those that are recognizable parts of fresh plants (leaves, stems, roots, fruits, seeds) or animals (cuts of meat, poultry or seafood, eggs), with nothing added or changed except in your own kitchen.
Harm from Processed Foods
Processed foods often have fiber and essential nutrients removed, and have extra sugar, salt and fats added to them. These changes increase risk for high blood pressure (Am J Hypertens, 2017; 30: 358-366), excess weight gain (Am J Clin Nutr, 2016;104:1433-1440), inflammation (Sao Paulo Med J, 2019; 137: 169-176), diabetes (JAMA Intern Med, 2020;180:283-291), cancer (BMJ, 2018;360:k322) and premature death (Public Health Nutr, 2019;22:1777-1785).
• A study from the National Institutes of Health (NIH) found that eating a lot of ultra-processed foods caused people to eat more calories and gain more weight than when they ate a minimally processed diet containing the same number of calories (Cell Metab, Jul 2, 2019;30(1):67-77.e3).
• This same study from NIH showed that eating processed foods makes you eat faster so that you are likely to eat more before your gut sends messages to your brain to tell you that you are full (Science, 2019; 363: 346-347). The subjects ate ultra-processed foods at an average rate of 37 grams and nearly 50 calories per minute. When they ate unprocessed foods, they ate an average of 30 grams at 32 calories per minute.
• Another study, from the Mayo Clinic estimated that 75 percent of packaged foods contain added sugars, which cause a high rise in blood sugar so your pancreas releases insulin that acts directly on your brain to make you hungry, and you eat more food (Health Psychol, 1985;4(1):1-24).
To help prevent diseases, maintain a healthful weight and prolong your life, I recommend a plant-based, Mediterranean-style diet that includes mostly unprocessed or minimally processed vegetables, fruits, un-ground grains, beans, nuts and other seeds. People who are overweight or diabetic should restrict foods made from any type of ground-up grains (flour).