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Most US Adults Fall Short of Cancer-Prevention Dietary Guidelines

The vast majority of American adults eat a dietary pattern that falls short of meeting national dietary guidelines for cancer prevention, a new study shows.

When researchers analyzed the dietary intake of more than 30,000 American adults according to BMI, the results also showed that people with BMIs in the obese range were the least likely to adhere to the dietary recommendations intended to reduce the risk for cancer.

The analysis measured self-reported dietary recalls and diet quality. Though the percentages of American adults who met each food source category differed, between almost 63% and 73% fell short of the recommended daily intake of fruits and vegetables and whole grains, and roughly 90% failed to meet the 30 g fiber per day recommendation.

The cancer prevention guidelines updated by the American Institute for Cancer Research in 2018 and the American Cancer Society nutrition and physical activity guideline closely mirror the 2020–2025 Dietary Guidelines for Americans recommended by the USDA—suggesting that most US adults are eating a suboptimal dietary pattern when it comes to nutrition-related disease prevention.

“We’re looking at individuals to move toward a primarily plant-based type of dietary pattern rich in fruits and vegetables, whole grains and beans, peas, lentils, seeds, and nuts—and cutting back on saturated fats and sodium,” says senior study author Colleen Spees, PhD, MEd, RDN, LD, FAND, an associate professor of medical dietetics in the School of Health and Rehabilitation Sciences at The Ohio State University. “Modifying our current dietary and physical activity patterns to better align with these evidence-based guidelines over time is important to reduce the risk of noncommunicable disease and promote lifelong health and wellness.

“If Americans adopt these recommendations, they can reduce their risk of obesity, cancer, cardiovascular disease, stroke, and high blood pressure.”

The study is published in the Journal of the Academy of Nutrition and Dietetics.

The research team used data from the National Health and Nutrition Examination Survey (NHANES), which collects health information on a nationally representative sample of about 5,000 individuals in the United States every year through interviews, laboratory tests, and physical exams.

The sample for this study included 30,888 adults aged 18 and older. The Ohio State researchers analyzed their BMI and data from 24-hour dietary recalls participants completed as part of the NHANES survey.

Almost 70% of the sample was classified as having overweight or obesity, and adults in the obesity range (35.9% of all participants) were significantly less likely than other adults to meet recommended intakes of fiber, fruit, nonstarchy vegetables, and whole grains. Adults with obesity also were more likely to exceed the recommended 18 oz per week of red meat and to have consumed fast food on the day of survey participation.

All groups, on average, consumed more added sugars than the recommended maximum of less than 10% of overall daily calories.

While basing the analysis on what survey participants reported eating over the previous 24 hours is a study limitation, Spees says previous studies have shown that 24-hour recalls can provide a representative snapshot of American dietary patterns.

Spees says these results also may reflect common “reductionist” views of dietary patterns among Americans—namely, the fixation on fad diets that often exclude certain food groups the public is led to believe can cancel out a lifetime of marginal eating patterns.

“Is coconut oil good for me? Is a single egg good for me, or not?” she says. “That’s a reductionist view and perspective when what really shapes and defines our health outcomes throughout life are dietary patterns—the cumulative patterns over time, and over years—as well as our patterns of behaviors, including our physical activity, our sleep patterns, our stress levels.

“It almost appears as if many Americans believe that if they can’t follow all of the recommendations, why should they adhere to any of them? And that’s just not the case. These guidelines don’t have to be so prescriptive. Even little changes in behavior can have a huge impact. For instance, reducing added sugars can help individuals achieve and maintain a healthy weight status over time.”

The USDA and cancer prevention agencies are the most reliable sources for not just what the guidelines are but also how to incorporate them into daily life, says Spees, who’s also an investigator at Ohio State’s Comprehensive Cancer Center.

Meeting some of the guidelines is far better than disregarding expert advice altogether, she says: Eat out at fast food restaurants a little less often and find tasty ways to incorporate more vegetables, grains, and beans into meals prepared at home. If you can’t exercise the suggested 150 minutes per week, then simply sit less and move more. And as you make such changes, do it gradually, in a way that's sustainable—ideally, for the rest of your life.

While this study found that people whose BMIs classify them as having obesity were the least likely to adhere to the guidelines, Spees says there’s a bigger problem to consider: “Most Americans, regardless of weight status, have much to improve when it comes to dietary patterns.”

— Source: The Ohio State University