More frequent cooking at home is associated with higher Healthy Eating Index-2015 score

To examine the association between cooking frequency and Healthy Eating Index (HEI)-2015, overall and by income, among US adults. Cross-sectional analysis using multivariable linear regression models to examine the association between cooking frequency and total HEI-2015 score adjusted for sociodemographic variables, overall and stratified by income. Nationally representative survey data from the USA. Adults aged ≥20 years (with 2 d of 24 h dietary recall data) obtained from the 2007 to 2010 National Health and Nutrition Examination Survey (n 8668). Compared with cooking dinner 0-2 times/week, greater cooking frequency was associated with higher HEI-2015 score overall (≥7 times/week: +3·57 points, P < 0·001), among lower-income adults (≥7 times/week: +2·55 points, P = 0·001) and among higher-income adults (≥7 times/week: +5·07 points, P < 0·001). Overall, total HEI-2015 score was higher among adults living in households where dinner was cooked ≥7 times/week (54·54 points) compared with adults living in households where dinner was cooked 0-2 times/week (50·57 points). In households in which dinner was cooked ≥7 times/week, total HEI-2015 score differed significantly based on income status (lower-income: 52·51 points; higher-income: 57·35 points; P = 0·003). Cooking frequency was associated with significant differences in HEI-2015 component scores, but associations varied by income. More frequent cooking at home is associated with better diet quality overall and among lower- and higher-income adults, although the association between cooking and better diet quality is stronger among high-income adults. Strategies are needed to help lower-income Americans consume a healthy diet regardless of how frequently they cook at home.