To examine national patterns in cooking frequency and diet quality among adults in the USA, overall and by weight-loss intention.

Analysis of cross-sectional 24 h dietary recall and interview data. Diet quality measures included total kilojoules per day, grams of fat, sugar and carbohydrates per day, fast-food meals per week, and frozen/pizza and ready-to-eat meals consumed in the past 30 d. Multivariable regression analysis was used to test associations between frequency of cooking dinner per week (low (0–1), medium (2–5) and high (6–7)), dietary outcomes and weight-loss intention.

The 2007–2010 National Health and Nutrition Examination Survey.

Adults aged 20 years and over (n 9569).

In 2007–2010, 8 % of adults lived in households in which someone cooked dinner 0–1 times/week and consumed, on an average day, 9627 total kilojoules, 86 g fat and 135 g sugar. Overall, compared with low cookers (0–1 times/week), a high frequency of cooking dinner (6–7 times/week) was associated with lower consumption of daily kilojoules (9054 v. 9627 kJ, P=0·002), fat (81 v. 86 g, P=0·016) and sugar (119 v. 135 g, P<0·001). Individuals trying to lose weight consumed fewer kilojoules than those not trying to lose weight, regardless of household cooking frequency (2111 v. 2281 kJ/d, P<0·006).

Cooking dinner frequently at home is associated with consumption of a healthier diet whether or not one is trying to lose weight. Strategies are needed to encourage more cooking among the general population and help infrequent cookers better navigate the food environment outside the home.