Food Processing and Health – The Nutrition Source

Nov 04, 2024

Processed foods are generally thought to be inferior to unprocessed foods. The term may suggest that a packaged food item contains many ingredients, perhaps even artificial colors, flavors, or other chemical additives. Often referred to as convenience or pre-prepared foods, processed foods are suggested to contribute to the obesity epidemic and the rising prevalence of chronic diseases like heart disease and diabetes. However, the definition of processed food varies widely depending on the source:

According to these standards, virtually all foods sold in the supermarket would be classified as “processed” to some degree. Because food begins to deteriorate and loses nutrients as soon as it is harvested, even the apples in the produce aisle undergo four or more processing steps before being sold to the consumer. That’s why in practice, it’s helpful to differentiate between the various degrees of food processing.

A popular system to classify processed foods was introduced in 2009, called the NOVA classification. It lists four categories considering the degree to which a food is processed and the purpose of these modifications: [2-4]

The NOVA system is recognized by the World Health Organization, Food and Agriculture Organization, and the Pan American Health Organization, but not currently in the U.S. by the Food and Drug Administration or USDA. NOVA has been criticized for being too general in classifying certain foods, causing confusion. For example, yogurt may fall into more than one category: plain yogurt is minimally processed, but fruited yogurt with added sweeteners could be labeled either processed or ultra-processed depending on how much sweetener and other chemical additives are incorporated. NOVA also does not provide comprehensive lists of specific foods in each category, so the consumer is left to guess where each may fall.

There’s no doubt that at least some processed foods are found in most people’s kitchens. There are benefits and drawbacks.

Depending on the degree of processing, nutrients can be destroyed or removed. Peeling outer layers of fruits, vegetables, and whole grains may remove plant nutrients (phytochemicals) and fiber. Heating or drying foods can destroy certain vitamins and minerals. Although food manufacturers can add back some of the nutrients lost, it is impossible to recreate the food in its original form.

Currently, bread and frozen meals are some of the most consumed ultra-processed foods in the U.S. [5] While these products can be good sources of whole grains, fiber, vitamins, and minerals, they can also be high in sodium, added sugars, and saturated fats. Given the variety of ultra-processed foods, it may be helpful to distinguish those with lower nutritional value from the broader category. Such distinction can be determined by evaluating a food’s nutritional content and long-term health effects. A product with an unevenly high ratio of calories to fiber and healthy nutrients (e.g., unsaturated fats, B vitamins, potassium) may be considered an “ultra-processed food of low nutritional value.” For example, soda provides high calories from added sugars and no healthy nutrients; and research supports an association between a high intake of sugar-sweetened beverages and an increased risk of obesity, diabetes, and heart disease. On the other hand, whole-grain bread and fiber-containing low-sugar breakfast cereals that may be fortified with nutrients such as folic acid have consistently been linked with lower rates of stroke. [6]

To help illustrate the spectrum of food processing, the table below includes ultra-processed foods of low nutritional value as its own category. We also we separate the NOVA categories of “unprocessed” and “minimally processed” foods, and omit NOVA’s “processed culinary ingredients” category, which mainly includes supplementary food components to assist in cooking and food preparation.

store-bought hummus made with chickpeas, spices, and oil without preservatives

Ingredients used widely in the production of ultra-processed foods such as saturated fats, added sugar, and sodium have become markers of poor diet quality due to their effect on heart disease, obesity, and high blood pressure. [8,9] It is estimated that ultra-processed foods contribute about 90% of the total calories obtained from added sugars. [5]

Food processing is a very broad spectrum that ranges from basic technologies like freezing or milling, to the incorporation of additives that promote shelf stability or increase palatability. As a general rule, emphasizing unprocessed or minimally processed foods in the daily diet is optimal. That said, the use of processed and even ultra-processed foods is the choice of the consumer, and there are pros and cons that come with each type. The Nutrition Facts Label and ingredients list can be useful tools in deciding when to include a more processed food in one’s diet. There is evidence showing an association with certain types of food processing and poor health outcomes, especially low-nutrient ultra-processed foods that contain added sugars, excess sodium, and unhealthful fats. But there also exist ultra-processed foods that have low amounts of these ingredients while being fortified in beneficial nutrients such as calcium, protein, fiber, and vitamins B and D.

Research is still clarifying if any harmful health effects from ultra-processed foods arise from the higher degree of processing or simply from the poorer nutritional quality often accompanying these types of foods. There is a growing range of processed and ultra-processed foods available, and some products may be a useful addition to a healthful diet.

You don’t have to avoid all processed foods but begin by adding more fresh or minimally processed ingredients to your shopping cart. More time may be needed to prepare these foods than just opening a can or popping a frozen container in a microwave, but the rewards may be fresher flavors, increased nutrients, and eating less additives that have no nutritional benefit.

Breakfast:

Lunch/Dinner:

Snacks:

Beverages: Your body appreciates plain water! Try it chilled with ice, warmed, or infused with fresh mint, slices of citrus fruit, or a piece of ginger.

Restaurants:

Last reviewed August 2023

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