How much does your food contribute to your risk of cancer? The most comprehensive study of this question, carried out by Imperial College London, tracked the dietary habits of nearly 200,000 British people aged 40–69, who revealed their food consumption every 24 hours for three years between 2009 and 2012 and were then followed up until January 31, 2021.

All food consumed was categorized according to its degree of food processing, and their consumption of ultra-processed food was noted as a percentage of their entire food consumption.

In case you’re wondering about the name “ultra-processed food,” the NOVA Food Classification System, designed by the Center for Epidemiological Studies in Health and Nutrition of the School of Public Health within the University of Sao Paulo, Brazil, has grouped food into four categories “according to the extent and purpose of the processing they undergo,” including any “physical, biological and chemical processes that occur after food is separated from nature.”

Group 1 is unprocessed or minimally processed foods, meaning they’ve just been cleaned, had some fraction like inedible bits of stem removed, or been ground, dried, fermented or pasteurized but had nothing added.

Group 2 is “processed culinary ingredients,” which includes products extracted from natural foods or nature. This grouping covers packaged grains like rice, fresh or pasteurized juices, pasta and other grains simply made from water and flour, all sorts of oils, salt, fats including coconut or butter, and any sort of sugar, plus honey.

Then there’s Group 3, the processed foods, which have salt, sugar, oil or other substances added to minimally processed foods (Group 2). This cluster of foods includes such things as tomato paste, canned or bottled vegetables or legumes, fruits in sugar syrup, bacon, canned fish, smoked meat or fish, freshly made cheeses and even bread that is unpackaged, made just with flour, yeast, water and salt.

Finally, there’s Group 4, the ultra-processed foods. These “foods” are made via a variety of industrial formulations. They start life as genuine foodstuffs like corn, wheat or sugar cane that are “fractioned” into particular substances (like sugar, oil, protein or starch) or as animal carcasses from intensive livestock farming that are pureed or ground.

This stuff is then put through chemical modifications like hydrogenation. More processes follow involving the assembly of food substances with little or no actual whole food anymore that have been extracted from real food (like oils and fats), plus food constituents (like hydrogenated fats). Or these substances are created, Frankenstein style, in the lab from food “substrates” such as flavor enhancers, emulsifiers, colors or food additives.

As NOVA points out, natural whole foods (Group 1) make up a tiny proportion of—or are even absent from—these foods.

This category includes any sort of packaged snacks or cookies, soft or energy drinks, instant soups or sauces, flavored yogurts, meat substitutes, breakfast cereals, sweetened juices, ready-meals and prepared dinners, anything called a “nugget,” most packaged bread and baked goods and cereals, cakes, and of course infant formulas.

So what you have in Group 4 is the human equivalent of canned dog food: substances that may have started out as something natural four or more processes ago but have, as the Imperial team put it, become “industrially derived food substances and food additives” put through “a sequence of extensive industrial processes”—and so manipulated through additives, pre-processing, extrusion, pre-frying and molding that by the time they reach your lips, they cannot remotely provide anything in the way of nourishment.

There’s also the fact that these processed goods have been deliberately manipulated to be “hyper-palatable”—that is, engineered to taste so good you are likely to eat too much of them, even to become addicted.

But here’s the astonishing part of it. According to the Imperial College team, half or more of the everyday British diet is made up of Group 4 foods—a percentage that may be even higher in other Western countries.

What’s more, every 10 percent increase in ultra-processed foods increased their cohort’s chances of developing cancer—particularly ovarian and brain cancers—or of dying from cancer, particularly breast or ovarian cancer. This is not to mention the evidence from other research that these non-foods have much to do with diabetes, heart disease and more.

After reading about how much sugar and other killer foods are in soft drinks and pizza, I paid a visit to a health store a few days ago. I was curious to see whether the same applies to processed health foods.

In many instances, it doesn’t—but not all. For instance, when I headed over to the baby food section, I spied a pot of baby food made by a reputable manufacturer known to create a load of excellent Group 2 foods.

According to the label, the sugar in that one 100-g pot was 12 g—equivalent to 3 teaspoons of sugar—meant to be a single serving to a baby less than a year old.

I then turned to little rice cake snacks, also intended for babies. Each two of these teeny rice cakes (about a quarter of the size of an adult-sized rice cake) had nearly 8 g of sugar—about two teaspoons of the white stuff.

The bottom line from Imperial’s findings: read every label.

Or, even better, follow one simple rule: throw away your ready-meals and cook organic whole foods from scratch.