Before you reach for a second slice of pizza or another breakfast croissant, it might be worth taking a closer look at what eating too many processed foods could mean for your health. From potential risks like weight gain to heart disease, filling your diet with processed foods may not be worth the momentary pleasure or convenience.
What Is Processed Food?
OK, but first, what exactly is processed food? When you think about it, anything that doesn't come straight from the ground or a tree is technically processed, says Lindsey Pfau, RD, owner of Rise Up Nutrition.
"If we're going to talk about the health implications or negative effects of processed foods, those are the foods that have additives and chemical ingredients that are used to enhance flavor and color as well as prolong shelf life," Pfau says. These foods not only contain chemical ingredients but also high levels of sodium, saturated and trans fats, and processed carbs that have little to no heart-healthy fiber, she adds.
Read more: Harmful Effects of Preservatives in Foods
So, while a healthy, low-sugar protein bar may be considered a processed food, it's better for you than the preservative-, sugar- and salt-laden culprits you should probably avoid. Below are the potential health risks associated with a diet full of unhealthy, processed foods.
1. Weight Gain and Obesity
Research hasn't clearly concluded that eating a diet high in processed food directly causes obesity, but there appears to be a link between consuming large amounts of these products and weight gain.
A December 2017 analysis published in Current Obesity Reports shows that four out of the five studies reviewed concluded that the consumption of processed foods may be associated with an increased risk of obesity, metabolic syndrome and high blood pressure as well as increases in total and LDL cholesterol (the dangerous kind). The researchers still can't pinpoint whether the obesity risk climbs due to the foods being processed or because of the nutrient content of processed foods.
A review sheds light on how eating too many processed foods contributes to the growing obesity epidemic in the U.S. Researchers found that potato chips, sugary drinks, sweets and desserts, refined grains and red and processed meats all contribute to weight gain the most, per the study published in Current Treatment Options in Gastroenterology.
"When it comes to obesity, how much you're eating and the balance of the rest of your diet matters," Pfau says, emphasizing that a diet high in fiber-rich carbs rather than refined carbs can help combat weight gain.
2. Type 2 Diabetes
Type 2 diabetes is a complex condition with a variety of risk factors, including things like age and genetics. But dietary habits are among the reversible factors, according to an April 2017 review published in the International Journal of Health Sciences. The review found that diets high in fried foods and sweets can up the risk of insulin resistance and type 2 diabetes.
What's more: A December 2019 study published in JAMA Internal Medicine found that a larger proportion of ultra-processed foods in the diet was associated with a higher risk of developing type 2 diabetes. After observing more than 100,000 subjects, researchers concluded that processed foods can increase the risk of type 2 diabetes even after taking lifestyle and sociodemographic factors into account.
Processed meats — think hot dogs, deli meats, bacon and sausage — have been linked to an increased risk of colorectal cancer, prompting the International Agency of Cancer Research (IARC) to classify them as a carcinogen, the American Cancer Society (ACS) reports. These meats have been salted, cured, fermented or smoked as a means to increase their shelf life or flavor.
In fact, data collected from more than 800 studies observed that eating 50 grams of processed meat every day increased the risk of colorectal cancer by 18 percent, according to the ACS. That may seem like a lot of meat, but 50 grams equals to about four strips of bacon or just one hot dog.
A January 2018 cohort study of almost 105,000 participants published in the British Medical Journal (BMJ) found that eating processed foods frequently was associated with higher overall cancer and breast cancer risk. However, the participants' food intake was self-reported, which Pfau warns can often be unreliable. The study authors write that more research is needed to understand the association between a diet high in processed foods and cancer risk.
A July 2015 paper published in Stroke suggests that there is an association between processed foods — specifically processed meats — and an increased risk of stroke. A diet high in processed foods is one that is often also high in sodium, which has been linked to an increased risk of stroke.
And when you're filling up on processed foods, there isn't much room for fresh fruits and vegetables, which are high in potassium. This combination could spell disaster, Pfau says, explaining that sodium and potassium control blood pressure. "Sodium can increase your blood pressure while potassium can decrease it."
When your blood pressure is elevated, blood flow through the arteries is restricted — and once blood flow to the brain is blocked, it can cause a stroke. What's more, Pfau says, high cholesterol levels could lead to blood clots, which can also block blood flow to the brain.
Plus, processed foods may also be high in trans fats — such as partially hydrogenated oils — which could contribute to high cholesterol, heart attack and stroke risk, Pfau warns.
5. Heart Disease
High blood pressure and stroke go hand-in-hand with cardiovascular disease; they're all interconnected, Pfau says. Like the link between sodium and stroke, consuming high amounts of sodium could also play a role in heart issues. And, Pfau says, processed foods containing trans fats could also increase your risk.
A May 2019 study in the BMJ found that eating too many processed foods was associated with an increased risk of heart disease. However, the authors note that more research is needed to better understand these associations.
6. Early Death
A February 2019 study published in JAMA Internal Medicine looked at over 44,000 middle-aged people in France and found that over a seven-year follow-up period, an increase in processed foods consumption was linked to a higher risk of death.
What's more, a May 2019 study in BMJ found that chomping on more than four servings of processed foods per day was associated with a 62 percent increased risk of dying from non-age-related causes. The researchers took it a step further and observed that for every additional serving of processed food, those chances increased by 18 percent.
"We have to remember the word 'risk,'" Pfau says. "No single food is going to cause stroke [or death] or even increase the risk for it. It's about the entire diet and lifestyle." Heather Caplan, RD, agrees: "We need to zoom out and see the full scope. I don't focus on a single food; there are so many other dietary factors to consider."
How to Avoid Processed Foods
Making a few simple swaps to your kitchen and your daily meals can help you cut down on the processed stuff significantly. Try these tips to get started.
- Empty your pantry of processed meats, packaged snacks and pastries and stock up on whole foods such as vegetables, fruits, lean meat and fish, nuts and whole grains.
- Replace your daily cold-cut sandwich and bag of potato chips with a piece of grilled chicken and roasted sweet potatoes over a bed of leafy greens.
- Instead of ending your meal with a brownie, reach for some fresh fruit.
- Current Obesity Reports: "Ultra-Processed Food Intake and Obesity: What Really Matters for Health—Processing or Nutrient Content?"
- American Cancer Society: "World Health Organization Says Processed Meat Causes Cancer"
- British Medical Journal: "Consumption of Ultra-Processed Foods and Cancer Risk: Results From Nutrinet-Santé Prospective Cohort"
- Acta Pharmacologica Sinica: "Dietary Salt Intake and Stroke"
- Stroke: "Diet and Stroke: Recent Evidence Supporting a Mediterranean Style Diet and Food in the Primary Prevention of Stroke"
- JAMA Internal Medicine: "Association Between Ultraprocessed Food Consumption and Risk of Mortality Among Middle-aged Adults in France"
- British Medical Journal: "Association Between Consumption of Ultra-Processed Foods and All Cause Mortality: SUN Prospective Cohort Study"
- British Medical Journal: "Ultra-Processed Food Intake and Risk of Cardiovascular Disease: Prospective Cohort Study (NutriNet-Santé)"
- International Journal of Health Sciences: "Effect of Diet on Type 2 Diabetes Mellitus: A Review"
- JAMA Internal Medicine: "Ultraprocessed Food Consumption and Risk of Type 2 Diabetes Among Participants of the NutriNet-Santé Prospective Cohort"
- Current Treatment Options in Gastroenterology: "Beyond the Calories—Is the Problem in the Processing?"