A top cancer doctor shares 4 bare minimum food rules to lower your chronic disease risk

• Making small changes to your diet can have a big impact on your health.
• Dr. Ezekiel Emanuel shared four tweaks he says give the most bang for your buck.
• He believes eating fermented foods is the easiest small change with the biggest benefit.

Dr. Ezekiel Emanuel wants you to stop obsessing over your health data and enjoy a treat from time to time. I experienced this firsthand when I met him for ice cream on a sunny Thursday afternoon in June to discuss his latest book on healthy living.

A specialty ice cream shop in London had formulated a limited edition pen-and-paper flavored ice cream for the UK launch of Emanuel's "Eat Your Ice Cream." It had a smoked wood flavor and was surprisingly good.

"I'm anti the wellness industrial complex," the oncologist, public health professor, and former Obamacare advisor told me matter-of-factly. The 68-year-old is "vehemently" against tracking, obsessing over, and maxxing our health, and advocates finding ways to fit wellness around your lifestyle, not the other way around.

In his latest book, he attempts to cut through the noise of the buzzy longevity trend that has gone mainstream by outlining the tenets of a healthy diet, including eating protein, healthy fats, and fresh produce.

As we scooped spoonfuls of ice cream from small metal bowls topped with chocolate flakes, he shared his top "bang for your buck" dietary changes to reduce the risk of chronic disease.

"Getting on the right diet is relatively simple," Emanuel told me. "There are four things you should do to start, and then there are things you can add."

But remember, "the occasional treat will not shave any minutes off your life, especially if you enjoy it with someone you love," he wrote in the book.

Stock up on fermented foods

Emanuel recommends adding fermented foods like sauerkraut, miso, kimchi, and kefir to your diet. He calls it "the easiest small change with big benefits."

The gut microbiome is host to trillions of microbes that impact our overall health. Studies suggest that people who eat fermented foods tend to have a more diverse gut microbiome, a sign of good health, a lower risk of obesity, and stronger immune systems.

This is because fermented foods contain prebiotics, which are plant fibers that the body can't fully digest, and live bacteria called probiotics. Both feed the "good" gut microbes and help increase the diversity of microbes in the colon lining.

"Pick whichever ones you like. They're really, really good for you," he said.

Can the soda

According to Emanuel, one of the best things you can do for your health is to stop drinking sugary soda, or at least cut down to one to two glasses a week.

Drinking one to two cans of soda a day increases your risk of developing type two diabetes by 26%, he said. It also increases the risk of heart disease, metabolic dysfunction-associated steatotic liver disease (MASLD), which is on the rise, and certain cancers.

A 12-ounce can of soda contains 140 calories, around 10 teaspoons worth of sugar, and has no nutritional value, Emanuel said.

Business Insider's Gabby Landsverk recently reported from a Washington DC nutrition conference that while diet sodas can be a helpful alternative to sugary drinks, they can still upset gut health.

Cut down on ultra-processed snacks

"We all have to cut back on the packaged snacks," Emanuel said.

Research suggests the average American gets around 60% of their daily calories from "junk" or ultra-processed foods that contain large quantities of salt, sugar, and fat, as well as additives.

Regularly eating this type of food (think packaged muffins, cookies, and potato chips) has been linked to an increased risk of a plethora of health conditions, including diabetes, cardiovascular disease, cancer, and depression. There's evidence that certain additives that are common in these foods can disrupt the gut microbiome, plus junk food rarely contains nutrients.

The term ultra-processed food has become somewhat contested among nutrition experts as it groups some dietary staples, such as packaged wholemeal bread, with junk food like doughnuts and hot dogs.

Emanuel prefers to use the term junk food for this reason.

Don't forget about fiber

Despite our cultural obsession with protein, most of us are getting enough already, Emanuel said. What most Americans are truly lacking is fiber.

Adults need about 30 to 35 grams of fiber a day, Emanuel said, but on average, most Americans get about half of that.

Fiber plays an important role in keeping the gut, cardiovascular, and metabolic systems healthy. It does this by slowing down the uptake of glucose into the bloodstream, curbing sugar spikes and crashes, and feeding the beneficial microbes in the gut.

Berries, pears, apples, kiwis, broccoli, sweet potatoes, beans, nuts, and whole grains are great sources of fiber, Emanuel said. He recommended starting by eating some fruit throughout the day and a salad with your dinner at night.