You constantly hear about how processed food is bad for your health and should be avoided. But what is it and why is it so bad?
In: Biology
Everything you do to food from the point that it comes out of the ground / off the tree or plant is processing, so it’s important to avoid pop-sci journalism headlines and dig into the nuance a bit.
Some types of food processing are vital to our survival. Humans, as a species, are the only animal to use fire to cook their food. This allowed our ancestors to broaden their diet, and survive on a wider variety of foods. For example, cows and other ungulates have multiple stomachs, just so they can extract the necessary amount of nutrition from grasses.
Instead of specializing in something so specific, humans just cook the food to help with nutrient extraction. Some nutrients are lost along the way, but cooking also helps us to digest things that we otherwise wouldn’t get sufficient nutrition from.
So what’s with all this talk about processed food being bad? Cooking is just one, very simple, method of processing food. Food is also processed mechanically, like grinding it up, and chemically, which can include heating things up or introducing other chemicals.
Some food processing results in higher caloric density. For example, if you were to sit down and eat an ear of corn, you’d eat a lot of fiber and water along with the corn kernels, which is where all the nutrition is. When we process corn, we dry it out, grind it up, and press it in to smaller pieces. These smaller pieces are much more nutritionally dense. This is good, but also bad. We don’t need *that much* corn in our diet. So by processing corn mechanically in a way that packs more into a smaller package, we introduce a lot of opportunities to over-consume it.
Chemically, we process foods to either make them last longer or to change their properties. One popular form of food processing is pasteurization. Pasteurization heats and/or pressurizes a food item in order to kill pathogens. On the whole pasteurization is a good thing. It makes food much safer, because it kills pathogens. It makes certain foods less healthy though.
For example, some foods contain beneficial bacteria. The pasteurization process can’t selectively kill microorganisms though. It just kills everything. So we lose some of the beneficial bacteria along the way. On the whole though, pasteurization is good processing.
One popular form of food processing that is extremely bad for you is hydrogenated fats/oils. This chemical process takes cheap food oils that are liquid and turns them into a solid at room temperature. These chemically engineered fats are very stable, meaning they will keep at room temperature for long periods of time. Hydrogenated fats are the reason you can buy a can of frosting off the shelf, and it will keep in the cupboard for months. Unfortunately, they’re also linked to an increased risk of heart disease.
The reality is that eating healthy requires you to stay on top of current scientific knowledge about diet and to avoid trendy pop-sci articles about foods that are good/bad for you. The easiest way to eat a healthy diet is to simplify what you eat. At one point, scientists heralded things like hydrogenated fats as a triumph of science. They soon learned that they were very wrong.
A simple diet that avoids processed foods and sticks to core dietary items that have been known to be good for us for decades is the easiest way to eat healthy. This means eating mostly vegetables, avoiding refined sugars and calorie-dense foods/snacks, limiting sodium/salt intake, and enjoying meat in reasonable portions.
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