The interplay between fat and bone deposition represents a physiologic trait enabling the body to choose between shuttling 'energy' towards accrual of a particular tissue. Plausibly the phenotype underlying obesity and diabetes risk may be determined by the differentiation of cell type (adipocyte, osteocyte, etc.) during this early stage of growth and development. In vitro studies demonstrate transdifferentiation under the influence of specific external stimuli, which can switch phenotypes toward other cell lineages. Further, rodent models have demonstrated that exposure to stimuli (exercise) early in life may prevent excess fat mass accrual in adulthood, even when the stimulus is later removed (animals are no longer exercising). Children's early experiences (engagement in physical activity) may 'environmentally induce' alterations in body composition and predispose individuals to diabetes throughout life (Figure 1).