Relationships between consumption of ultra-processed foods, gestational weight gain and neonatal outcomes in a sample of US pregnant women.

Background: An increasingly large share of diet comes from ultra-processed foods (UPFs), which are assemblages of food substances designed to create durable, convenient and palatable ready-to-eat products. There is increasing evidence that high UPF consumption is indicative of poor diet and is associated with obesity and metabolic disorders. This study sought to examine the relationship between percent of energy intake from ultra-processed foods (PEI-UPF) during pregnancy and maternal gestational weight gain, maternal lipids and glycemia, and neonatal body composition. We also compared the PEI-UPF indicator against the US government's Healthy Eating Index-2010 (HEI-2010).

Methods: Data were used from a longitudinal study performed in 2013-2014 at the Women's Health Center and Obstetrics & Gynecology Clinic in St. Louis, MO, USA. Subjects were pregnant women in the normal and obese weight ranges, as well as their newborns ( = 45). PEI-UPF and the Healthy Eating Index-2010 (HEI-2010) were calculated for each subject from a one-month food frequency questionnaire (FFQ). Multiple regression (ANCOVA-like) analysis was used to analyze the relationship between PEI-UPF or HEI-2010 and various clinical outcomes. The ability of these dietary indices to predict clinical outcomes was also compared with the predictive abilities of total energy intake and total fat intake.

Results: An average of 54.4 ± 13.2% of energy intake was derived from UPFs. A 1%-point increase in PEI-UPF was associated with a 1.33 kg increase in gestational weight gain ( = 0.016). Similarly, a 1%-point increase in PEI-UPF was associated with a 0.22 mm increase in thigh skinfold ( = 0.045), 0.14 mm in subscapular skinfold ( = 0.026), and 0.62 percentage points of total body adiposity ( = 0.037) in the neonate.

Discussion: PEI-UPF (percent of energy intake from ultra-processed foods) was associated with and may be a useful predictor of increased gestational weight gain and neonatal body fat. PEI-UPF was a better predictor of all tested outcomes than either total energy or fat intake, and a better predictor of the three infant body fat measures than HEI-2010. UPF consumption should be limited during pregnancy and diet quality should be maximized in order to improve maternal and neonatal health.