The American diet has changed dramatically over the past two centuries, and the most notable changes include the increase in the consumption of processed and ultra-processed foods (for example, the biggest food-related change in the last 50 years could be the fact that, for the first time in recorded human history, people eat too much). American adults have reduced their consumption of household food and have reduced the time spent cooking since 1965, but this trend seems to have stabilized and there has been no substantial decline after the mid-1990s. This study aims to assess whether American adults continue to increase their consumption of food outside the home or if this trend has stabilized and, when people eat at home, how likely they are to cook and how much time they spend cooking, especially among low-income consumers. Because home-cooked foods are still the most important source of Americans' diets, a more effective approach could seek to increase the health of the foods that people prepare and consume at home.
There is no evidence to suggest that the trend of increasing food consumption outside the home should continue indefinitely, and American consumers may have already peaked in terms of the amount they eat away from home. Although this study uses nationally representative surveys on diet and time use, since neither survey takes into account both food intake and time use, the association between food preparation and daily energy cannot be examined. The lowest-income group consumed the highest proportion of domestically sourced food in all years, while the highest-income group consumed the least amount of domestically sourced food in all years. The percentage of daily energy from household food sources declined by similar amounts in all income groups, but low-income people consumed a higher proportion of food from household sources over all years.
Data on food availability does not include information on processing before sale, where food was sold, how it was prepared and consumed, or consumer profiles (2). Figure 1 shows the trends in total energy intake and energy consumed from household food sources by income group. Despite consuming 72% of their daily energy from household food sources, people with lower incomes seem to be increasingly less likely to cook, suggesting that they rely more on foods that require little preparation rather than eating out more. Chains such as Panera Bread, Shake Shack and Chipotle have helped introduce the so-called fast and informal restaurant concept, which is based on freshly prepared food with quality ingredients that cost only nominally more than fast food in terms of money and time.
However, little is known about whether these trends have continued in the 21st century and whether they are consistent among people with low incomes, who are increasingly being targeted by public health programs that promote home cooking. Using dietary data, trends in people's food supply were examined in relation to the average total daily energy intake. In all dietary surveys, the proportion of energy consumed at home and outside the home for adults was determined using variables about the food source and where it is eaten.