Grocery aisles are lined with shelves of processed foods. And while there's nothing quite like the satisfying crunch of a potato chip, you're probably no stranger to the fact that processed foods can have some negative effects on your health.
In fact, 50 percent of a typical American's diet is made up of ultra-processed food, recent data from the American Heart Association (AHA) states.
Read more from our 'What Really Happens to Your Body When' series.
What Is Processed Food?
Processed foods are much more than just packaged cereals or fast food.
Technically, "processed foods" are foods that have been cooked, frozen, packaged or changed in nutritional composition, according to the Academy of Nutrition and Dietetics.
Processed foods can range from minimally to more heavily processed.
- Minimally processed foods: Foods that have been packaged or preserved at peak freshness, such as canned tomatoes, pre-cut veggies, tuna or frozen fruit fall into this category.
- Heavily or ultra-processed foods: Ready-to-eat foods are on the more heavily processed side. These include things like crackers, granola and deli meat. The most heavily processed foods are usually pre-made meals like frozen TV dinners.
Processed foods are often blamed for being the cause of diet downfalls — but not all of them deserve the bad reputation they're given.
In some cases, processing can actually provide added vitamins and nutrients due to fortification. Fortification is when certain nutrients are added to the food in order to improve nutrient density.
For instance, milk is fortified with vitamin D (which is not naturally present in milk), a nutrient most of us don't get enough of.
Pasteurization is another form of food processing that benefits, rather than harms, your health.
This process applies heat to food (often dairy) in order to destroy any potentially harmful bacteria, according to the International Dairy Foods Association. Without this form of food processing, many dairy products could be risky to consume.
Alongside some of these health benefits, processed or packaged foods can also be more convenient for anyone with a busy lifestyle, dietitian Sarah Schlichter, RD, says.
"Not everyone has the time, energy or availability to cook from scratch every night," she says.
"For example, I'd encourage a busy mom preparing dinner for her family of six to buy pre-cut or frozen vegetables, a rotisserie chicken and bread to feed everyone — and that can make for a completely healthy and balanced meal. Processed foods can fill the gaps while still providing nutrients — and sanity."
But, of course, the more heavily processed foods can be detrimental to your health if you're eating them too much or too frequently.
Many times, processing can take away from the food's natural vitamins and minerals (think: peeling the skin off fruit and veggies as well as whole grains to make white bread or refined-grain products), according to the Harvard T.H. Chan School of Public Health.
Processed foods have been linked to overeating and weight gain since they can be dense in calories.
People following a highly processed diet tend to eat around 500 more calories than participants following a minimally processed regimen, according to a small July 2019 study in Cell Metabolism. As a result, people following the highly processed meal plans gained more weight on average and ate faster, too.
Eating too quickly can make it difficult to identify satiety cues, causing overeating in some cases, according to Harvard Health Publishing.
What's more, eating more ultra-processed food is associated with a higher risk for obesity, according to a December 2017 review published in Current Obesity Reports.
It is unclear if the high risk for obesity is due to the processing of the food, which strips it from important nutrients, or because processed foods often pack in more ingredients such as sugar, which tacks on more calories.
Although there's no one ingredient or ultra-processed food that has been shown to directly cause cancer, a highly processed diet has been linked to an overall increased risk of death, according to a May 2019 study in the BMJ, which analyzed the diets of almost 20,000 men and women over 5 years.
In this study, the main cause of death was cancer and the risk of death by all causes was observed to be 62 percent greater for those with the highest amount (more than four servings per day) of ultra-processed foods.
What's worse is the risk of death by all causes was observed to increase by 18 percent with just one additional serving of processed food per day.
Another May 2019 study in the BMJ looked at over 100,000 people and found that eating ultra-processed foods was associated with an increased risk of heart disease.
Some of the types of foods they found associations with were ultra-processed fats and sauces, meats, sugary products, processed beverages and salty snacks.
Using data of more than 13,000 adults, researchers observed an overall decrease in heart health for every 5 percent increase in calories from ultra-processed foods, according to research presented in November 2019 by the U.S. Centers for Disease Control and Prevention.
High sodium levels are related to high blood pressure, a risk factor for heart disease and stroke, according to the AHA. Given that a majority of Americans' sodium comes from processed foods, choosing reduced-sodium options, for instance, is a measure you can take to minimize the negative effects of ultra-processed foods.
Look for the AHA's Heart-Check mark on packaged foods. The AHA's Heart-Check Food Certification Program is created to help inform consumers on which processed foods are lower in saturated fat, cholesterol and sodium. Foods with the checkmark also provide at least 10 percent of the Daily Value of either vitamin A, vitamin C, iron, calcium, protein or fiber.
A healthy gut is one that has a diverse number of bacteria — in type and in number.
Your diet has the potential to change the composition of the bacteria in the gut. In fact, diets rich in fiber can promote the growth of healthy gut bacteria and reduce inflammation in the gut, according to an August 2019 review published in Microorganisms.
Fermented foods, such as yogurt and sauerkraut, have also been shown to promote a healthy gut.
In addition, researchers may be getting closer to an answer on whether or not artificial sweeteners are good or bad for your gut health. According to an October 2019 review in Nutrients, artificial sweeteners negatively altered gut bacteria in people who did not normally consume them.
Researchers also found a link between artificial sweeteners and glucose intolerance.
The Bottom Line on Processed Foods
An increase in highly processed food in the diet typically means that the diet has lower amounts of fruits and vegetables, which are main sources of antioxidants and fiber — and are essential for good health.
Do your best to prioritize minimally processed foods over the ultra-processed fare, which should be eaten in moderation.
"We don't need to eliminate all processed foods from our diets, as there is a spectrum of processing involved," Schlichter reminds us.
If they occupy a large part of your diet, ultra-processed foods can have long-lasting negative effects on your health. But if you eat them wisely, prioritizing more minimally processed options with the occasional ultra-processed indulgence, these foods can be a part of a balanced, nutritious lifestyle.
Additional reporting by Bojana Galic.
- Academy of Nutrition and Dietetics: "Processed Foods: What's OK and What to Avoid"
- International Dairy Foods Association: "Pasteurization"
- Harvard T.H. Chan School of Public Health: "Processed Foods and Health"
- Cell Metabolism: "Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake."
- Harvard Health Publishing: "Why Eating Slowly May Help you Feel Full Faster"
- British Medical Journal: "Ultra-processed Food Intake and Risk of Cardiovascular Disease: Prospective Cohort Study (NutriNet-Santé)"
- American Heart Association: "Too Much Ultra-Processed Foods Linked to Lower Heart Health"
- AHA: "Can Processed Foods Be Healthy Infographic"
- AHA: "Heart-Check Food Certification Program Nutrition Requirements"
- BMJ: Association between consumption of ultra-processed foods and all cause mortality: SUN prospective cohort study
- Current Obesity Reports: "Ultra-processed Food Intake and Obesity: What Really Matters for Health – Processing or Nutrient Content?"
- Harvard Medical School: "Gut Feelings: How Food Affects Your Mood"
- Microorganisms: "The Role of Gut Microbiota in Intestinal Inflammation with Respect to Diet and Extrinsic Stressors"
- Nutrients: "Food Components and Dietary Habits: Keys for a Healthy Gut Microbiota Composition"