We investigated changes in body composition in 3,088 free-living participants of the UK Biobank imaging study. Statistical models utilised organ and tissue segmentations from the neck-to-knee Dixon acquisitions and multiecho sequences of the liver/pancreas. A significant decrease in grip strength was observed, and small, but statistically significant, decreases in all skeletal muscle measurements. Significant increases in visceral adipose tissue and intermuscular fat in the thighs were also found in the absence of changes in BMI, waist circumference and ectopic-fat deposition. We have shown that even after a relatively short period of time significant changes in body composition are observable.