How does body fat affect buoyancy?

• A. More body fat increases buoyancy because fat is less dense than muscle.
• B. More body fat decreases buoyancy because fat is heavier.
• C. Body fat has no effect on buoyancy.
• D. Buoyancy depends only on bone density.

Answer: (A)

Buoyancy is about whether your body's average density is lighter or heavier than water. Fat tissue is less dense than water (about 0.9 g/mL) while muscle is denser (around 1.06 g/mL) and bone is even denser. When you have more fat, the overall average density of your body drops, so your body displaces enough water to stay afloat more easily. In short, increasing fat lowers your density and increases buoyancy, making you float better.