Many factors including exercise and metabolic hormones regulate bone homeostasis and maintain bone sufficiently strong for everyday activity protecting against falls and factures. However, with age effectiveness of the skeletal system to withstand habitual loads without fractures or accumulating microdamage declines, and injuries become frequent. Therefore, it is hard for elderly adults and those with bone wasting disorders to exercise with sufficient intensity to influence bone strength. It is known, that concentrations of gastro-entero-pancreatic hormones change before and after eating and many have potent regulatory effects on bone. We hypothesised that the timing of food ingestion affects bones’ response to mechanical loading.

Using a well-established tibial axial loading model, we performed experiments to determine osteogenic effects of mechanical loading that mimics exercise after different periods of withholding food or feeding in young adult and aged mice. Here we show that food ingestion for 2 hours, but not 1 hour or 3 hours, following overnight (16-hour) fast potentiated bones’ adaptive response to osteogenic mechanical loading in young, but not aged mice. Furthermore, we found that changing timing of feeding can turn an ineffective loading stimulus that does not normally cause bone formation, into an effective one. Concentrations of metabolic hormones, with known regulatory effects on bone including ghrelin, leptin, insulin, GIP and GLP1 changed during fed and fasted 2-hour fed states in young and aged mice, however, there were age-related differences in hormone secretion.

Our findings indicate associations between the timing of feeding and bone adaptation. These findings have potential for translation into benefits for people by providing information on when to exercise in relation to meals, which may help to build and maintain healthy musculoskeletal system throughout the life-course.