Objective: To examine the effect of fast-food and full-service restaurant consumption on adults' energy intake and dietary indicators. Design: Individual-level fixed-effects regression model estimation based on two different days of dietary intake data was used. Setting: Parallel to the rising obesity epidemic in the USA, there has been a marked upward trend in total energy intake derived from food away from home. Subjects: The full sample included 12 528 respondents aged 20-64 years who completed 24 h dietary recall interviews for both day 1 and day 2 in the National Health and Nutrition Examination Survey (NHANES) 2003-2004, 2005-2006, 2007-2008 and 2009-2010. Results: Fast-food and full-service restaurant consumption, respectively, was associated with an increase in daily total energy intake of 813·75 kJ (194·49 kcal) and 858·04 kJ (205·21 kcal) and with higher intakes of saturated fat (3·48 g and 2·52 g) and Na (296·38 mg and 451·06 mg). Individual characteristics moderated the impacts of restaurant food consumption with adverse impacts on net energy intake being larger for black adults compared with their white and Hispanic counterparts and greater for middle-income v. high-income adults. Conclusions: Adults' fast-food and full-service restaurant consumption was associated with higher daily total energy intake and poorer dietary indicators.
KeywordsFast food Full-service restaurant Food away from home Energy intake Obesity Diet qualityThe USA is one of the most obese nations in the world, with the age-adjusted prevalence of obesity at 35·5 % among adult men and 35·8 % among adult women in 2009-2010 (1) . With obesity linked to diabetes, heart disease, stroke and some cancers (2) , health-care spending attributed to obesity reached $US 147 billion in 2008, and the costs are projected to increase dramatically in the future (3) . Parallel to the rising obesity epidemic, there has been a marked upward trend in total energy intake derived from food away from home (FAFH). In 1977-1978, the contribution of intake from fastfood and full-service restaurants to total energy intake was 14·2 % for young adults (aged 19-39 years) and 11·5 % for older adults (aged 40-59 years) (4) . In 2007-2008, the contribution of restaurant energy to total energy intake increased to 24 % (13 % for fast-food and 11 % for full-service restaurants) for adults aged 20-64 years (5) . In addition, in 2007-2008, on a given day, 36 % and 27 % of US adults aged 20-64 years consumed foods and beverages from fast-food and full-service restaurant sources, respectively (5) . Moreover, FAFH as a share of food expenditures increased gradually from 30 % in 1977 to 43 % in 2012, although its share stagnated and declined slightly to about 42 % in the recent recession (2007)(2008)(2009) (6) .A number of studies have found an association between FAFH consumption and greater total energy intake and poorer nutrient intakes among adults (7)(8)(9)(10)(11) . Adults who ate fast food had higher intakes of energy, total fat, saturated fat and Na, and...