Childhood obesity, is fast food exposure a factor?

Can we estimate the causal effects of diet and sedentary behavior on schoolchildren’s overweight/obesity from observational studies?

“…Brazilian schoolchildren who consumed such a lunch which concentrated most of the daily energy intake had lower obesity risk compared to other dietary patterns based on the time of day of eating events [33]. This is in line with the present study finding that frequent eating ("snacking") increases the risk of overweight/obesity and some reviews shared this concern, especially in the context of social isolation during the coronavirus disease (COVID) epidemic [32][33][34].…”

“…Causal analysis with observational study data has a strong foothold in econometrics and public health, especially for evaluating the impact of policy regulations on an area level (county, district, state), and in epidemiological analyses of the impact of public health interventions such as vaccination, using synthetic cohort method [6,[29][30][31][32]. It usually requires a large sample size to guarantee a sufficient number of comparable case and control units, particularly if the effect size is small, such as in the present study.…”

“…However, it is worth noticing that the application of Mendelian randomization has been growing exponentially in medical research, including the field of nutrition [54,55]. When the genetic analysis is unavailable, other designs that improve similarities between the baseline characteristics of the groups under comparison are still available [5,6,9,31,32]. The best design to evaluate the effectiveness of the interventions to prevent overweight/obesity-a matter of ongoing debate [56][57][58]-may benefit from a causal analysis, despite some skeptical views held by those who think confounding is ubiquitous in observational studies [2].…”

Swallow This: Childhood and Adolescent Exposure to Fast Food Restaurants, BMI, and Cognitive Ability

“…In contrast, Howard et al (2011), Asirvatham et al (2019), and Langellier (2012 find no such relationship. Other papers examine exposure at the place of residence, with estimates likewise ranging from increases in BMI (Elbel et al, 2020;Qian et al, 2017) to no effects (Lee, 2012;Dolton and Tafesse, 2022). The literature studying exposure in adulthood is also inconclusive, with Anderson and Matsa (2011) finding no link between fast food restaurants and obesity, while Giuntella (2018) reports a positive association and excess weight gain in pregnant mothers.…”

Fast food proximity and weight gain in childhood and adolescence: Evidence from Great Britain

“…The majority of the evidence on this question comes from cross‐sectional data (Cobb et al., 2015 ; Feng et al., 2010 ; Fraser et al., 2012a ; Harrison et al., 2011 ; Maguire et al., 2015 ; Mason et al., 2018 ; Snowdon, 2018 ; Walker et al., 2010 ; Williams et al., 2013 ), with the ensuing issue that associations may reflect socioeconomic deprivation, for instance, rather than the presence of fast food restaurants. A few papers attempt to estimate causal relationships, and are mostly confined to specific regions in the US (Alviola et al., 2014 ; Anderson & Matsa, 2011 ; Asirvatham et al., 2019 ; Currie et al., 2010 ; Davis & Carpenter, 2009 ; Dunn, 2010 ; Dunn et al., 2012 ; Powell, 2009 ; Qian et al., 2017 ), and Dolton and Tafesse ( 2022 ) in the UK. The general finding from the US literature is that the impact of fast food restaurants is significant but fairly small, with the one UK study finding no impact, suggesting fast food restaurants play a limited role in rising levels of childhood obesity.…”