The relationship between human beings and food in the 21st century is strange. For most of our time on the planet (roughly two million years), humans were hunters and gatherers, and their food was whatever they could find, collect, or kill. Within the past 10 to 13 thousand years, humans started making the switch to agriculture, and food became whatever we could grow or domesticate on a farm. Within the past 200 years, though, food processing has exploded to an alarming extreme, and, as a result, we have had to make up some new words and phrases to make sense of what’s going on.

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Some new, made-up words:

• Food product: A food product is something that would probably be unknown to a hunter-gatherer. Examples include ketchup, mayonnaise, cereal, and — some would argue — bread. These things are called “food products” to differentiate them from “whole foods.”
• Whole food: A “whole food” can be simply defined as “not a food product.” It is unprocessed and has no additives. Examples include: an apple, a handful of nuts, or a head of lettuce. To our ancestors from a million years ago, the phrase “whole food” wouldn’t really make sense (even if they somehow spoke English). To them, whole foods were just “foods.” In this way, “whole foods” only exist in a world where most foods are processed.

To many people today, avoiding food products and emphasizing whole foods seems intuitive. To some, it might seem like the latest fad diet. Regardless, eating a diet that is rich in whole foods is a pillar of the Spartan lifestyle, and there are many reasons why we believe that the Spartan nutrition plan is the best for human beings.

Why Should You Eat a Diet Rich in Whole Foods?

1. Because whole foods, unlike processed foods, have a 2-million-year track record.

It is estimated that the earliest beings that could reasonably be called humans appeared on the planet some 2 million years ago. Back then, human beings did not have sophisticated ways of processing their foods, so it is safe to say that all of their foods were whole foods.

Related: 7 Major Health Benefits of Eating a Plant-Based Diet

If we assume that our bodies adapt to their environments, it is reasonable to think that our bodies are adapted to digest the foods that we ate for millions of years. Whether or not those foods are “good” or “bad” for us is beside the point; the fact is, whole foods work well with our bodies; they have always worked well; they will probably always work well.

2. Because processed foods generally have reduced nutrient content.

Imagine a tomato severed from its stem and left out in the sun for 1,000 days. Eventually, if it is not eaten by an animal, that tomato will turn into a pile of mush, and, finally, into a pile of dust.

This happens because the natural tendency of all matter in the universe is to become more and more disordered. We see this every day in the natural world. All living things survive — on a cellular level — by using energy to organize small, simple particles into larger, more complex molecules that can perform complicated tasks. By contrast, the decay of organic matter is essentially all of those complex molecules relaxing, letting go, and turning back into their simple components.

Related: This Plant-Powered Super Salad Will Help You Crush the Spartan Whole-Food Challenge

What does this have to do with processed food?

Because whole foods closely resemble the plants and animals that they came from, they start out with a relatively high level of molecular organization. For us, this also means that they have a very high nutrient content. (Many essential nutrients, such as folic acid and riboflavin, are highly-complex molecules.) As soon as we start applying heat to those whole foods, the complex molecules —including essential nutrients that our bodies cannot produce on their own — start to degrade. The more processing, the more degradation.

You wouldn’t want to eat a 1,000-day-old tomato, right?

3. Because there is a lot of evidence that regular consumption of fruits, vegetables, and whole grains decreases the risk of certain diseases.

For starters:

• Coronary heart disease (CHD) and heart attacks. Consumption of flavonoids (chemicals found in plant food sources) has been linked to lower mortality from CHD, fewer heart attacks, lower bad cholesterol (LDL), and lower total cholesterol.
• Heart disease. Increased intake of fruits and vegetables has been linked to a 27% lower mortality from cardiovascular disease, a lower risk of stroke, lower stroke mortality, lower mortality from coronary heart disease, and lower all-cause mortality.
• Cancer. Consuming more fruits and vegetables has also been linked to a 35% reduced risk of prostate cancer, a decreased risk of colon cancer, a decreased risk of colorectal cancer in both men and women, and a 22% lower risk of death due to cancer.

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4. Because whole foods are generally cheaper.

Food products, unlike food, do not grow naturally. (That much is obvious.) They require artificial methods of production besides photosynthesis and cellular respiration, and these methods require alternative fuel sources: electricity, fossil fuels, and others. When we pay for processed foods, we pay not only for the food itself, but for the processing and packaging.

Outside of increased convenience in the short term, neither of these extra expenses does us a lot of good. The processing depletes the food of nutrients, and the packaging ends up in a landfill. Whole foods, like fruits and vegetables, are nutrient-dense and package-less — and therefore not only cheaper, but also healthier and more sustainable.

In the spirit of delaying gratification, let’s give up a little bit of convenience in the here and now for the sake of the long-term good.

5. Because nutrients in isolation don’t do much good.

Here is an example. People used to think that taking B-Carotene would prevent lung cancer. After all, it’s a strong antioxidant found in fruits and vegetables, and there were some strong epidemiological studies supporting that idea. But more recent studies found that B-Carotene alone didn’t help at all; in fact, it might have hurt.

Related: 5 Reasons Why Athletes Need Flavonoids in Their Diets

Other isolated nutrients have also failed to improve health. Vitamin C supplements were found to have no significant effect on the risk of CHD or cancer. Vitamin E did little to improve the heart health of patients in the HOPE study. In the words of Rui Hai Liu, Professor of Food Science at Cornell University, “No single antioxidant can replace the combination of natural phytochemicals in fruits and vegetables to achieve the observed health benefits.”

What do you think?

If these five arguments hold up, then the smart thing to do would be to cut out processed foods and eat more fruits, vegetables, nuts, whole grains, legumes, and leafy greens.