Very High Weight Gain During Exclusive Breastfeeding Followed by Slowdown During Complementary Feeding: Two Case Reports

There is consistent evidence that both high weight and rapid weight gain during early infancy are associated with development of overweight or obesity later in childhood and adulthood (Druet et al., 2012; Weng, Redsell, Swift, Yang, & Glazebrook, 2012; Young, Johnson, & Krebs, 2012). Researchers conducting systematic reviews and meta-analyses have suggested that the odds of childhood overweight and obesity are lower in breastfed infants (Monasta et al., 2010; Victora et al., 2016; Weng et al., 2012; Yan, Liu, Zhu, Huang, & Wang, 2014), but some researchers have not found a protective effect (Casazza et al., 2013; Kramer et al., 2007). A large cohort study conducted by van der Willik, Vrijkotte, Altenburg, Gademan, and Kist-van Holthe (2015) reported that a high body mass index (BMI) in infancy (≥ 1 SD BMIfor-age at 6 months) increased the odds of childhood obesity at 60 to 72 months of age regardless of feeding method. They suggested that exclusively breastfed infants with high weight gain were not protected against later obesity. Even though reported results were inconsistent, it is still the general belief among health personnel that there is no reason to worry about exclusively breastfed infants with high weight gain (Danish Health Authority, 2015). However, little is known about the possible causes of high weight gain seen in some exclusively breastfed infants and to what degree these infants have a higher risk of obesity later in childhood. Thus, health professionals lack adequate evidence-based recommendations for exclusively breastfed infants with high weight gain. We present two cases of infants having very high weight gain during exclusive breastfeeding followed by a decrease in weight-for-age z-scores (WAZ) during complementary feeding. To explore potential factors that might have influenced their very high weight gain, we analyzed the macronutrient concentration in human milk, breastfeeding frequency, and human milk intake at 4 to 5 months. Furthermore, we followed the weight of the two children until 24 and 42 months of age.