To examine the association between household food insecurity and overweight, obesity and abdominal obesity in Mexican adults.

Cross-sectional study.

We analysed data from the Mexican Halfway National Health and Nutrition Survey 2016, a nationally representative survey that accounted for rural and urban areas in four regions of Mexico: North, Centre, Mexico City and South.

Adults from 20 to 59 years old (n 5456, which represents 45 804 210 individuals at the national level).

70·8 % of the Mexican adults had some degree of household food insecurity. This situation showed larger proportions (P < 0·05) among indigenous people, those living in a rural area, in the Southern region or the lowest socio-economic quintiles. The prevalence of obesity and abdominal obesity was higher in female adults (P < 0·001), with the highest proportions occurring among those experiencing severe household food insecurity. Among women, mean BMI and waist circumference were higher as household food insecurity levels increased (P < 0·001). According to multivariate logistic regression models, severe household food insecurity showed to be positively associated with obesity (OR: 2·36; P = 0·001) in Mexican adult females.

Our findings confirm the association between household food insecurity and obesity among Mexican women. Given the socio-demographic characteristics of the food-insecure population, it is alarming that prevailing socio-economic inequalities in the country might also be contributing to the likelihood of obesity. Therefore, it is crucial to maintain and bolster surveillance systems to track both problems and implement adequate policies and interventions.

To validate the telephone modality of the Latin American and Caribbean Food Security Scale (ELCSA) included in three waves of a phone survey to estimate the monthly household food insecurity prevalence during the COVID-19 pandemic in Mexico.

We examined the reliability and internal validity of the ELCSA scale in three repeated waves of cross-sectional surveys with Rasch models. We estimated the monthly prevalence of food insecurity in the general population and in households with and without children and compared them with a national 2018 survey. We tested concurrent validity by testing associations of food insecurity with socio-economic status and anxiety.

ENCOVID-19 is a monthly telephone cross-sectional survey collecting information on the well-being of Mexican households during the pandemic lockdown. Surveys used probabilistic samples, and we used data from April (n 833), May (n 850) and June 2020 (n 1674).

Mexicans 18 years or older who had a mobile telephone.

ELCSA had an adequate model fit and food insecurity was associated, within each wave, with more poverty and anxiety. The COVID-19 lockdown was associated with an important reduction in food security, decreasing stepwise from 38·9 % in 2018 to 24·9 % in June 2020 in households with children.

Telephone surveys were a feasible strategy to monitor reductions in food security during the COVID-19 lockdown.