Yes, eating out too often is bad for you

We know that people who eat out frequently are more likely to develop obesity, diabetes, and other chronic health conditions, likely because restaurant and fast foods tend to be more calorie-dense, nutrient-poor, and higher in fat and sodium than what you might make at home. So it might seem obvious to conclude that those who eat out a lot are more likely to die of a heart attack or develop cancer.

As you know, however, medicine is not math, and the Transitive Property of Equality (if A=B and B=C then A=C) doesn't necessarily apply. Today's article tries to connect those dots (J Acad Nutr Dietetics 2021;121(9):1741-1749).

The authors analyzed data gathered between 1999-2000 and 2013-2014 as part of the National Health and Nutritional Examination Survey (NHANES), an ongoing, large-scale, long-term study of Americans living all over the United States. For the purposes of today's article, the authors included participants who were at least 20 years old in 1999-2000 and did not have cardiovascular disease or cancer: over 35,000 people.

During the extensive interviews conducted as part of the survey, the participants were asked how many times in the previous 7 days they had a meal that was "prepared away from home in places such as restaurants, fast food places, food stands, grocery stores, or from vending machines". That frequency was then classified in five increasing levels ranging from less than 1 meal per week (on average) to 2 meals or more per day.

As part of the survey the participants receive a physical exam from a physician and respond to detailed questionnaires assessing not only their health and demographic information, but also dietary factors. This allowed the authors of this article to take into account the quality of the participants' overall diet as well as factors ranging from race/ethnicity to smoking status to physical activity and Body Mass Index.

Today's article compares the frequency of dining out for those participants who passed away during the study period with those who did not. The authors were able to ascertain the cause of death through NHANES' link to the National Death Index.

In particular, the researchers were interested in all-cause mortality (those who died of any cause), cardiovascular mortality (for example: dying of a stroke or heart attack), and cancer mortality (dying of cancer of any type).

The results are predictable, but still surprising: compared to those who ate out the least, those who ate out 2 times a day or more were 49% more likely to die of any cause, 18% more likely to die of a heart attack or other cardiovascular event, and 67% more likely to die of cancer.

This was after taking into account not only demographic and health factors, but also what the participants actually ate.

What this means for you

Eating out is an important part of life but staying home more often than eating out is healthier but also less expensive.