consuming a ‘western’ dietary pattern were at higher risk of GDM (RR 1.27; 95% CI 1.03, 1.56) in one meta-analysis of 13 cohort studies (Hassani Zadeh, Boffetta, and Hosseinzadeh 2020) with a similar effect size that was marginally non-significant in 2 other meta-analyses due to the lower confidence limit (Haghighatdoost et al. 2023; Quan et al. 2021).

Higher maternal adherence to a healthy diet (defined in various ways) was protective for GDM in 10 of 11 effect estimates (including between 6 and 26 studies), with the effect size ranging from 0.39 (95% CI 0.31, 0.48) for a high quality diet that adhered to national dietary guidelines to 0.86 (95% CI 0.76, 0.96) for a healthy dietary pattern rich in fruits, vegetables and whole grains (Haghighatdoost et al. 2023). Higher quality diet, as measured by higher adherence to Mediterranean, DASH, AHEI or plant-based diets, also was associated with lower risk of gestational diabetes (range of OR 0.51-0.66).

**_Hypertensive disorders of pregnancy_** - Higher maternal adherence to a healthy diet was associated with lower risk of gestational hypertension (OR 0.86) (Abdollahi et al. 2021) and pre-eclampsia (OR 0.78) (Kibret et al. 2019). Risk of pre-eclampsia was also lower among pregnant women consuming adequate vegetables and fruit, based on 4 and 5 studies in LMICs, respectively (Kinshella et al. 2021). Conversely, unhealthy dietary pattern adherence increased the odds of gestational hypertensive disorders (OR 1.23) (Abdollahi et al. 2021) and maternal diets rich in UPF also were associated with increased risk of pre-eclampsia (OR 1.28) (Paula et al. 2022).

## **Birth outcomes**

Seven (7) SRM summarized the evidence for the contribution of diet during pregnancy to neonatal birth outcomes such as preterm birth, birth weight/length, small/large-for-gestational-age, and low birthweight (LBW). The odds of preterm birth were lower among pregnant women with healthy dietary pattern adherence, with estimates from meta-analyses of 6-10 studies ranging from 0.44 to 0.79 (Abdollahi et al. 2021; Chia et al. 2019; Kibret et al. 2019).

Evidence was also available on the association of maternal diet characteristics to the infant’s birth weight and length. Low dietary diversity during pregnancy was associated with an increased risk of having a LBW baby (OR 2.04) based on 9 studies in Africa (Seid et al. 2023). An _unhealthy_ dietary pattern (high intake of refined grains, processed meat, and foods high in saturated fat or sugar) was associated with lower birth weight (mean difference -40 g; 95% CI -61, -20) in 3 studies but the pooled effect size for birth weight among mothers with high adherence to _healthy_ dietary patterns during pregnancy in 13 studies (n=25,499) was close to zero (Chia et al. 2019). Yet higher maternal adherence to a healthy diet was associated with higher birth weight (mean difference +0.19 g; 95% CI 0.05, 0.32) in a meta-analysis of 15 studies (n=75,041) by Abdollahi et al. (2021) as well as lower risk of LBW (OR 0.72; 0.53, 0.97), based on 7 prospective cohort studies. Milk consumption during pregnancy was associated with higher birth weight (mean diff =51.0 g; 95% CI 24.7, 77.3) and birth length (mean diff 0.33 cm; 95% CI 0.03, 0.64), as well as lower risk of small-for-gestational-age (OR 0.69; 95% CI 0.56, 0.84) and LBW (OR 0.63; 95% CI 0.48, 0.84) (Pérez-Roncero et al. 2020).

# Children < 5 years of age

Evidence on the risk of malnutrition associated with nutrient-inadequate and unhealthy diets for children less than five years of age includes nine (9) SRM articles with effect size estimates (see **Table 5** ). Diet diversity is a recommended measure of nutrient adequacy for this age group in LMICs. We found only three SRMs, all based on studies from Ethiopia, that looked at the association of low diet diversity in children < 5 years with stunting (Abdulahi et al. 2017) and anemia (Azmeraw et al. 2023; Belachew and Tewabe 2020). The evidence for dietary risk factors for overweight and obesity in children <5 years was also very limited, with one SRM on breastfeeding and three SRMs that included overweight and/or obesity among children 1-21 years as an outcome. There is strong evidence across 159 studies that breastfeeding is protective against overweight or obesity among children 1-9 years (pooled OR 0.73, 95% CI 0.71, 0.76), with subgroup analysis showing an even higher effect size for LMICs (OR 0.70; 95% CI 0.64, 0.78) (Horta et al. 2023). Breastfed children are also at lower risk for diabetes in later life, with a 9