Nutritional Strategies Prescribed During Pregnancy and Weight Gain in Women with Gestational Diabetes Mellitus: A Systematic Review of Observational Studies

Background/Objectives: This systematic review aims to identify diets related to weight gain in pregnant women diagnosed with gestational diabetes mellitus (GDM). Methods: This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, and its protocol was registered on the International Prospective Register of Systematic Reviews (CRD42023432322). The searches used the medical subject headings in the PubMed/MEDLINE, Web of Science, Scopus, and EMBASE databases. Studies were selected, and data were extracted by three researchers. The Newcastle-Ottawa Scale (NOS) and the Joanna Briggs Institute (JBI) tool were used to assess methodological quality. Results: Six articles were included, most of them of the cohort type, with nutritional strategies lasting 2-15 weeks for overweight/obese women, based on the "macronutrient-adjusted diet" and "calorie-adjusted diet". Only one study addressed dietary counseling in weight management, and none considered the dietary pattern. The gestational weight gain was 4.91-13.8 kg, and a lower weight gain was found in all studies that used the "macronutrient-adjusted diet" nutritional strategy. However, it did not meet the gestational weight gain targets. Conclusions: Despite the limited number of studies examining the impact of nutritional strategies on weight gain in women with GDM, some research suggests that diets focused on macronutrient adjustment may lead to less weight gain but are not adequate. Therefore, future studies are needed to evaluate which type of nutritional strategies ensure weight gain control during pregnancy.