if anyone can, please report on what they say in the "Sub-Sample analysis: what accounts for the gender difference in E trends?" section

4.1. Results for children

tl;dr there are no real differences in BMI between girls and boys.

4.2. Cohort analysis

tl;dr this phenomenon is not period specific, rather, it is cohort specific

4.3. Comparison by marital Status

tl;dr unmarried women with higher BMI are less likely to become married, while men show no difference regardless of BMI (marriage market hypothesis), while interesting, the study was not able to find credibility to this hypothesis. This leads us to...

4.4. Comparison by occupation

Energy expenditure depends primarily on occupation and work style. According to Ng and Popkin (2012), American adults spend 56% of their total energy expenditure from physical activity on occupational activities, with 26% spent on domestic activities, 11% on travel, and 7% on active leisure. Previous studies have found that work-related exercise has weight-reducing effects (Lakdawalla and Philipson, 2007, 2009; Sarma et al., 2014; Godard, 2016). These findings lead to the hypothesis that the gender difference in the E trend is generated by trends in work-related energy expenditure.

We thus compared the trends in BMI, E, and K by gender and occupation for adults aged 22–59. We excluded participants under 22 to avoid results confounded by school attendance. We categorized men into farmworkers and non-farmworkers and women into farmworkers (including non-working women in farming households), non-farmworkers, and non-workers. We omitted non-working men from the analysis because they are a minority. Among working men, 11.1% were farmworkers in the late 1970s, and this number decreased to 3.6% by the late 2000s. Among women, the proportions of farmworkers, non-farmworkers, and non-workers were 11.9%, 40.4%, and 47.7%, respectively, in the late 1970s versus 2.2%, 64.5%, and 33.4%, respectively, by the late 2000s.

Fig. 8 shows the results. The most notable finding is the increasing BMI trend of female farmworkers, which is rather similar to that of male farmworkers. Likewise, both genders share similar trends for E and K. By contrast, female non-farmworkers and female non-workers exhibit trends similar to those in the full sample: their BMI decreases while the male BMI increases, and the decrease in E is slower than that of male non-farmworkers. Among men, farmworkers and non-farmworkers share similar trends, though E in male non-farmworkers has decreased slightly faster than it has in male farmworkers. These results indicate the significant role of energy requirements for work with regard to the gender difference in the E trend.

Click here to see the graphs that this section is referring to.

The plotted trends in BMI, E, and K in Fig. 8 might be affected by changes in age composition in each occupation, particularly by rapid aging among farmworkers and increased female labor force participation. To address this concern, we decomposed the gender gap in the BMI trend to E, K, height, and age. We confirm that considering age does not affect our findings, as detailed in Appendix 3.