Total body electrical conductivity, abbreviated TOBEC, is a method of measuring body composition — how much of the body is fat versus lean tissue. The person lies inside a chamber surrounded by an electromagnetic coil; lean tissue, with its water and electrolytes, conducts electricity far better than fat, so the conductivity reading reveals the proportion of fat-free mass. It was developed as a quick, non-invasive alternative to underwater weighing and remains a research tool in nutrition and physiology laboratories. Like all body-composition methods it estimates rather than directly measures, and hydration status affects the reading. It is accurate enough for group studies but too cumbersome for routine clinical use.