For more than a decade since he began studying nutrition, Kenny Mendoza has been paying attention to his food labels, scrutinizing grams of fat, protein, and added sugar.

But people eat food, not isolated nutrients. And, as Mendoza realized while training for his doctorate at Harvard, those foods are often heavily processed before reaching our plates, which can make a huge difference for our health.

"Now, I also pay much more attention to all the ingredients beyond the nutrients in the foods, to see if they're ultra-processed," he told Business Insider. "The evidence says that both things are important, nutrients and food processing."

Today, as a professor of public health at the University of Texas Southwestern Medical Center, Mendoza said his research has changed how he eats.

His latest work suggests that small, actionable food choices can make an important difference in colon cancer risk, at a time when the disease has become the leading cause of cancer-related death in younger people.

Mendoza shared two of the most compelling swaps to prevent cancer, as well as his personal strategies to make healthy eating simpler.

The top culprits behind colon cancer risk

Mendoza and colleagues from Harvard wanted to estimate how cancer risk might change if people ate fewer processed foods.

Researchers analyzed decades of dietary and health data from more than 200,000 US healthcare professionals. They modeled what would happen to their cancer risk if they ate more of some foods, and less of others.

They found a small but significantly reduced risk in obesity-related cancers, such as breast and colorectal cancer, was linked to cutting back on ultra-processed foods like refined carbs and packaged snacks by just 10% (measured as a share of total calories).

That's like cutting out 20-ounce soda, a small order of fries, or three to four pieces of bacon from a regular diet of 2000 to 2500 calories a day.

The swaps that matter

Mendoza said not all processed food is equally bad for our health. Two types of processed food are most closely linked to higher cancer risk: processed red meats and sugary drinks. He avoids them completely — and recommends others do, too.

Mendoza's research also found that a specific food swap offers a double whammy for cancer prevention.

His study found that replacing a serving of ultra-processed bread with a serving of whole-grain cereal (such as oatmeal) was associated with a small but significant reduction in cancer risk.

The swap is doubly beneficial because you're replacing preservatives that can harm your health with nutrients that protect it.

Processed bread contains emulsifiers, which are linked to inflammation that drives cancer risk. In contrast, whole grains contain fiber and B vitamins, which help stave off cancer.

And if you're used to a breakfast sandwich with bacon, a good cancer-fighting alternative is yogurt. Research suggests it plays a uniquely supportive role in gut health (in addition to providing key nutrients like protein and B vitamins).

"Despite the fact that some yogurts are ultraprocessed, they still retain active cultures, which are the live bacteria that basically help your gut bacteria to be healthier," Mendoza said.

One caveat: some flavored yogurts are more likely to contain lots of added sugar or thickeners. Your best bet is to pay attention to labels and opt for plain, unsweetened yogurt and mix in toppings like honey, berries, or nuts and seeds.

You may not be able to eliminate processed food — even top nutrition scientists eat them occasionally. But a good first step is ditching the soda, processed meat, and white bread in favor of more whole grains and yogurt for a healthier gut.

This article is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your qualified physician or healthcare provider.