Impact of seasonal scarcity on energy balance and body composition in peasant adolescents from Calakmul, Campeche Mexico

Abstract

A time allocation and anthropometric study were performed on 46 male and 38 female adolescents from 16 peasant households from two different adaptive strategies in the municipio of Calakmul, Campeche Mexico to see if they could maintain energy balance during the annual scarcity season. These strategies were called: "household subsistence agricultural strategy" (HSA) and "household commercial agricultural strategy" (HCA). Each month, from June 2001 to May 2002, adolescents were measured and followed for 24 h. Their activities were recorded at 15 min intervals. Weight for age (W/A), height for age (H/A), body mass index (BMI), arm muscle area, arm fat area, total energy expenditure (TEE), activity energy expenditure (AEE), and basal metabolic rate (BMR) were estimated and the data compared between seasons using a repeated measurements analysis of variance. The results suggest that HCA offers their adolescents better buffering against seasonal scarcity, and that HSA males are better protected than females. HCA adolescents didn't show significant losses of weight, and HCA females lost body fat during the scarcity season. HSA vulnerability was observed in W/A and BMI z score reductions during the scarcity season. It also reflected itself in stunted adolescent males and adolescent females with fewer fat reserves. HSA adolescents reduced their BMR to down regulate their energy expenditure during the scarcity season without reducing TEE and physical activity levels. HSA females lost muscle mass during the scarcity season while HSA males didn't. This difference was associated with a more demanding work schedule throughout the year for females.