Eating Like Adults: An Investigation of Dietary Change in Childhood and Adolescence at Portus Romae (Italy, 1st–4th Centuries C.E.).

Previous isotopic studies of Roman diet for individuals buried at Isola Sacra (first–fourth centuries C.E.; Italy) have focused on variation in adult diet or the critical stages of breastfeeding and weaning during infancy and childhood; however, little is known about the characteristics of diet when a child transitioned through adolescence to adulthood. This paper uses dietary stable isotope analysis of incremental tooth dentin from nine individuals (15 teeth, 52 incremental dentin sections) to investigate the transition between childhood and adult diet, and sex-specific dietary patterns for people buried in the necropolis of Isola Sacra in the early Roman Empire. The incremental dentin isotope data demonstrate that males and females consumed different diets as early as 4.5 years of age. Females exhibit a positive correlation between δ15N and age (rs = .41, p = .026), suggesting the greater inclusion of higher trophic level foods as they aged. However, no discernable pattern of dietary change is identified for males, suggesting sex-based dietary variation. For males, isotopic evidence of protein insufficiency around 15 years of age for two individuals raises questions about the effects of pubertal development on protein requirements, as well as changing social roles for young men during adulescentia. This research highlights the importance of considering diet in a longitudinal fashion and working to understand the biological and social changes occurring during adolescence in the past.