Dr. Larry Cohen had always eaten his vegetables—as long as they arrived on top of a burger. “And the tomato had to be in the form of ketchup,” says the emergency room physician at UCHealth Memorial Hospital Central in Colorado Springs. Then, in 1999, five-foot-six Cohen hit 197 pounds. His vanity wounded, Cohen joined a gym, went on a calorie-restricted diet, and lost 50 pounds. Nevertheless, a few years later Cohen began experiencing heart problems while training for a triathlon. A angiogram revealed arterial plaque, buildup that bypass surgery couldn’t completely clear. So, Cohen researched plaque-eradicating foods and adopted a whole-foods, plant-based diet with no added oils or fats and less than 10 percent of daily calories from fat. A year later, the blockage was gone. Convinced that food is the most powerful medicine in the world, in 2017 Cohen became one of the first Colorado doctors certified by the American Board of Lifestyle Medicine, which promotes healthy eating (plus other habits, like plenty of sleep and exercise) as a way to prevent and improve chronic disease. Now 67 and a svelte 137 pounds, Cohen broke down the numbers that really matter when it comes to food and your health.

~50: Percentage of deaths in the United States from heart disease, stroke, and type 2 diabetes in a single year that were associated with “suboptimal eating habits”—that is, not eating enough nuts and seeds, omega-3 fatty acids from seafood, vegetables, fruits, whole grains, and polyun-saturated fats and chowing down instead on high-sodium foods, red meat, and sugary beverages—according to a 2017 study published in the Journal of the American Medical Association.

One: Poor diet’s rank among the major causes of death; it surpassed tobacco use in 2017, according to research in the Lancet about the global burden of disease. The study showed that the problem is not just what people are eating (too much salt, fat, etc.), but also what people aren’t eating—not enough fruits and vegetables, whole grains, and fiber from whole foods. “I’m not a big fan of telling people what they have to eat,” Cohen says, “but it’s really frustrating sometimes when we have this powerful tool for making people healthy.”

5–7: Servings of fruits and vegetables you should be eating every day. Fruits and vegetables provide fiber and also contain phytochemicals, vitamins, and antioxidants, Cohen says, that together have been shown to reduce the risk of some chronic diseases.

8:30 a.m.: The time, on the Sundays he’s not working, that Cohen leads Walk With A Doc at Cottonwood Creek Park in Colorado Springs. As part of the nationwide program, Cohen strolls with anyone who wants to participate and answers their questions concerning lifestyle and health. Find a Walk With A Doc chapter near you by visiting walkwithadoc.org.

80%: The share of chronic diseases—like high blood pressure, stroke, and heart disease—that can be prevented, and even reversed, by adhering to lifestyle medicine, according to Cohen.

30–35: Grams of fiber Cohen recommends ingesting daily. Highly concentrated in whole-grain foods and legumes, fiber can lower mortality from not just cardiovascular disease but also from infectious and respiratory diseases, in part because certain gut bacteria feed on fiber and then produce short-chain fatty acids that actually help heal the gut and improve your immune system.