By Jamie Smith. Medically reviewed by Amy Richter, RD Nutrition
Processed foods, such as ready meals, baked goods, and processed meats, can have negative health effects. Most food needs some degree of processing, and not all processed foods are bad for the body. However, chemically processed foods, also called ultra- processed foods, tend to be high in sugar, artificial ingredients, refined carbohydrates, and trans fats. Because of this, they are a major contributor to obesity and illness around the world.
In recent decades, ultra-processed food intake has increased dramatically worldwide. These foods now account for 25–60% of a person’s daily energy intake throughout much of the world. This article looks at how processed foods can affect a person’s health and what to avoid.
What are processed foods?
The term “processed food” can cause some confusion because most foods are processed in some way.
Mechanical processing — such as grinding beef, heating vegetables, or pasteurizing foods — does not necessarily make foods unhealthful. If the processing does not add chemicals or ingredients, it does not tend to lessen the healthfulness of the food.
However, there is a difference between mechanical processing and chemical processing. Chemically processed foods often only contain refined ingredients and artificial substances, with little nutritional value. They tend to have added chemical flavoring agents, colors, and sweeteners. These ultra-processed foods are sometimes called “cosmetic” foods, as compared with whole foods.
Are processed foods bad for you?
Ultra-processed foods tend to taste good and are often inexpensive. However, they usually contain ingredients that could be harmful if consumed in excess, such as saturated fats, added sugar, and salt. These foods also contain less dietary fiber and fewer vitamins than whole foods.
One large study, involving more than 100,000 adults, found that eating 10% more ultra-processed foods was associated with a 10% increase in the risks of cardiovascular disease, coronary heart disease, and cerebrovascular disorders.
The researchers reached this conclusion after accounting for saturated fat, sodium, sugar, and fiber intake. Other research indicates that eating highly processed foods can lead to weight gain.
Below, we look at seven reasons why processed foods can increase the risk to a person’s health.
- 1. Added sugar
Processed foods tend to contain added sugar and, often, high fructose corn syrup. Added sugar contains no essential nutrients but is high in calories.
Regularly consuming an excess of added sugar can lead to compulsive overeating. It is also linked with health conditions such as obesity, metabolic syndrome, type 2 diabetes, and inflammatory diseases.
Processed foods and beverages are among the major sources of added sugar in the diet. Sweetened beverages are a particularly significant source; people tend to consume much more sugar than they realize in soft drinks.
Cutting down on added sugar — by drinking sparkling water instead of soda, for example — is a quick and effective way to make the diet more healthful.
- 2. Artificial ingredients
The ingredients list on the back of processed food packaging is often full of unrecognizable substances. Some are artificial chemicals that the manufacturer has added to make the food more palatable.
Highly processed foods often contain the following types of chemicals:
- artificial coloring
- chemical flavoring
- preservatives, which keep the food from going bad quickly
- texturing agents
Also, processed foods can contain dozens of additional chemicals that are not listed on their labels. For example, “artificial flavor” is a proprietary blend. Manufacturers do not have to disclose exactly what it means, and it is usually a combination of chemicals.
Official organizations have tested most food additives for safety, though the use of these chemicals remains controversial among doctors and researchers.
- 3. Refined carbohydrates
Carbohydrates are an essential component of any diet. However, carbs from whole foods provide far greater health benefits than refined carbohydrates.
The body breaks down refined, or simple, carbohydrates quickly, leading to rapid spikes in blood sugar and insulin levels. When these levels then drop, a person may experience food cravings and low energy.
Because refined carbs cause frequent increases and decreases in blood sugar, consuming them is linked with an increased risk of type 2 diabetes. Highly processed foods are often high in refined carbohydrates.
- 4. Low in nutrients
Ultra-processed foods are very low in essential nutrients, compared with whole or minimally processed foods. In some cases, manufacturers add synthetic vitamins and minerals to replace nutrients lost during processing.
However, whole foods provide additional healthful compounds that ultra-processed foods do not. Fruits, vegetables, and grains, for example, contain healthful plant compounds with antioxidant, anti-inflammatory, and anticarcinogenic effects. These include flavonoids, anthocyanins, tannins, and carotenoids.
The best way to get the full range of essential nutrients is to eat whole, unprocessed, or minimally processed foods.
- 5. Low in fiber
Dietary fiber has a wide range of health benefits.
Fiber can slow the absorption of carbohydrates and help people feel more satisfied with fewer calories. It also acts as a prebiotic, feeding the friendly bacteria in the gut, and can help boost heart health.
Most ultra-processed foods are very low in fiber, as natural fiber is lost during processing. Healthful high fiber foods include:
- nuts and seeds
- whole grains
- 6. Quick calories
The way that manufacturers process foods makes them very easy to chew and swallow. Because much of the fiber is lost during processing, it takes less energy to eat and digest ultra-processed foods than whole or less processed foods. As a result, it is easier to eat more of these products in shorter periods. In doing so, a person consumes more calories — and uses fewer in digestion — than they would if they had eaten whole foods instead.
This increases a person’s chances of taking in more calories than they use up, which can lead to unintentional weight gain.
- 7. Trans fats
Ultra-processed foods are often high in unhealthful, cheap fats. For example, they often contain refined seed or vegetable oils, which can be easy to use, inexpensive, and last a long time. Manufacturers create artificial trans fats by adding hydrogen to liquid vegetable oils, making them more solid.
Trans fats increase inflammation in the body. They also raise levels of low-density lipoprotein, or “bad,” cholesterol, and decrease levels of high-density lipoprotein, or “good,” cholesterol. Eating trans fats is associated with an increased risk of heart disease, stroke, and type 2 diabetes. For example, according to a 2019 study, a 2% increase in energy intake from trans fats is linked with a 23% increase in cardiovascular risk.
The best way to avoid refined oils and trans fats is to avoid processed foods. A person can replace these with healthful alternatives, such as coconut oil or olive oil.
In recent decades, ultra-processed foods have become common in diets worldwide. However, eating large amounts of these foods increases risks to health.
To rebalance the diet or make it more healthful, a person can replace ultra-processed foods with whole foods, including grains, nuts, seeds, lean meats, fruits, vegetables, and legumes.