For example, for a typical adult, and holding constant other variables, a lunch in a table-service restaurant has on average 184 more calories (kcal) than a lunch made at home. A lunch at a fast-food restaurant has on average 121 more calories than a lunch made at home.
A difference of 120 to 180 kcal per day is enough to contribute to weight gain over time.
Two concerns about restaurant meals are their energy density and their total calories. Binkley found that fast-food meals were the most energy dense, while table-service restaurant meals had the most total calories. Meals from home scored better on both counts.
From the Wiley-Blackwell press release:
“It is misleading to focus concerns about the nutritional effects of increased food away from home primarily on fast food. All food away from home should be considered,” Binkley concludes.