Processed & Unprocessed Foods
Did you know that in 2015 the WHO (World Health Organization) announced that processed meats are connected to cancer (click here to view)? Most people never heard about it, as the meat companies are far stronger financially, and unfortunately there is a clear interest to protect the companies’ profits rather than the public’s health.
Not only that; many studies found a direct connection between how often people eat out and their likelihood of developing certain diseases. And as you can guess, most restaurant food is processed.
So, what do we mean when we say “processed foods”? Because, let’s be honest— even when we steam a vegetable, we can technically call it “processed” in a way.
This is why there are four different categories of processed food:
1. Unprocessed and Minimally Processed Foods
Unprocessed foods are raw foods such as fresh fruits, vegetables, nuts, and seeds (that are not roasted or salted!). Minimally processed foods may also be dried, crushed, ground, filtered, roasted, boiled, fermented, pasteurized, chilled, frozen, or vacuum-packed, as long as there’s no extra salt, sugar, or other added ingredients.
This minimal processing makes natural foods better suited for travel and storage but keeps them mostly pure.
Frozen vegetables are a good example of minimally processed foods that keep their integrity as whole food.
2. Processed Culinary Ingredients
This group contains calorie-dense foods you rarely eat by themselves, such as oils, butter, sugar, and non-caloric ingredients like salt. How these ingredients impact your metabolic fitness largely depends on context. For example, roasting fresh vegetables in olive oil will have a different effect than drinking coffee with added sugar.
Some oils in this category are best avoided entirely. For example, processed seed oils like soybean oil are among the most common sources of fat in the American diet but are some of the worst oils for metabolic fitness. This is because processed seed oils can contain high amounts of linoleic acid, an omega-6 fatty acid that prompts fat cells to store more fat.
The ratio of omega-6 to omega-3 fatty acids used to be around 1:1 in ancient humans’ diets but is as high as 20:1 in the modern diet, which increases the risk of obesity. Research has shown that these enlarged fat cells also spike inflammatory proteins that may lead to insulin resistance.
3. Processed Foods
Manufacturers combine foods from the first two groups—for example, canned fish in salty brine or fruit preserved in sugar syrup—creating processed foods with longer shelf lives.
Like minimally processed foods, processed foods may be canned, frozen, or fermented.
The easiest way to tell the difference is by scanning the label for added ingredients, even just salt or oil.
Processed foods usually have at least three ingredients, and often several more—slightly modified versions of recognizable foods.
Most cheeses, tofu, and processed meats like ham, bacon, smoked fish, and pastrami fall into this category.
Whole-grain bread that only has the same ingredients you’d use at home (flour, yeast, salt) falls into this category; a bread that also contains emulsifiers, coloring, or additives belongs to the ultra-processed group.
Whether processed foods can be part of a healthy diet depends on context and ingredients.
For example, flaxseed crackers have just a few whole ingredients, no added sugar or salt, and minimal processing—so you still get the health benefits of the whole food.
However, it’s easy to consume too much fat, salt, and especially sugar from this category.
Read labels carefully, as sugar hides under dozens of names in everyday foods like peanut butter and ketchup.
4. Ultra-Processed Foods
A study that looked at Americans’ eating habits over six years found that ultra-processed foods made up the majority of calories in most people’s diets and increased across nearly all demographics between 2007–2012.
And it’s not just fast food, frozen meals, or breakfast cereal—this category includes seemingly “healthy” energy bars and protein shakes.
Manufacturers create these products by combining extracted parts of foods or synthetic ingredients like preservatives.
First, they break down whole foods to create raw materials like oil, sugar, starch, protein, and fiber—often extracted from just a few crops (corn, wheat, soy, sugarcane, or beets).
These foods may also contain trans fats, which manufacturers create through hydrogenation. Adding hydrogen makes fats solid at room temperature and extends shelf life—but with major health costs.
Next, some products undergo further chemical modifications. Hydrolysis uses enzymes to extract proteins, carbohydrates, natural flavorings, and colorings from ingredients.
These parts are then mixed with other food derivatives and synthetic additives.
The result is ultra-processed foods: mass-produced pastries, breads, cakes, cookies, nut milks, “nuggets” made of ground meat, fish, or soy substitutes, and most chips, crackers, and snack foods.
A healthy, clean diet should avoid these foods. They have little nutritional value, and consuming their excess salt, sugar, and unhealthy fats increases the risk of diabetes, heart disease, obesity, and even depression.
A review of studies showed that the highest intake of ultra-processed foods increased the risk of overweight/obesity by 39% and metabolic syndrome by 79%, alongside low HDL (“good cholesterol”).
Studies also show that diets high in ultra-processed foods correlate with high consumption of refined sugars, saturated and trans fats, and low intake of protein, fiber, and essential vitamins and minerals.
(It’s also worth noting the environmental cost: for example, it takes more than 94 pounds of corn to make a single bottle of corn oil.)
How Ultra-Processed Foods Impact Metabolic Health
Trans Fats Alter Insulin Sensitivity
Although natural trans fats from meat and industrial trans fats both affect plasma lipoproteins (HDL and LDL cholesterol), research shows that industrially created trans fats are far more likely to promote inflammation and cellular stress, which are linked to insulin resistance and metabolic diseases.
Trans fats disrupt liver function and have been shown to cause liver damage in mice.
They also inhibit insulin sensitivity—possibly by altering insulin receptor signaling.
Because of these strong links to disease, the Food and Drug Administration (FDA) banned artificial trans fats (partially hydrogenated oils) in 2018. However, most countries have not taken that step.