Those of us who eat home-cooked meals have lower levels of potentially harmful chemicals in their blood.
Tools used to prepare restaurant and takeaway meals and some packaging may be to blame.
Perfluoroalkyl (PFAS) and polyfluoroalkyl substances, are a group of synthetic chemicals that are resistant to heat and do not easily degrade.
Because of this, they are used in some cookware and stain-resistant materials.
Studies in the US have found the chemicals in the blood of 97-100% of adults and children.
Diet is thought to be a key factor.
To investigate further, Susmann and colleagues (2019) looked at how eating habits affect PFAS levels, analysing data from more than 10,000 participants in the US National Health and Nutrition Examination Survey from 2003 to 2014.
Participants provided blood and information on food sources.
PFAS were detected in three out of every four samples. Levels were lower in those who ate more meals at home, and higher among those who ate out or ate more fast food.
For every 1,000 kilocalories of food eaten from non-restaurant sources each day, the concentration of PFAS dropped by up to 5%.
Microwave popcorn raised levels, possibly due to chemicals in packaging.
There is some evidence to suggest PFAS may cause cancer and weight gain, and affect fertility, child development and the immune system.
Scully, R.P. (2019) Eating Out can bring a Side Serving of Suspect Chemicals. New Scientist. 19 October 2019, pp.18.
Susmann, H.P., Schaider, L.A., Rodgers, K.M. & Rudel, R.A. (2019) Dietary Habits Related to Food Packaging and Population Exposure to PFASs Environmental Health Perspectives. 127(10). https://doi.org/10.1289/EHP4092.