Why Muscle Raises Resting Energy Use
Even when you are still, your body is not idle. Muscle cells continually repair proteins, maintain their internal chemistry, and keep the machinery ready to contract. Those tasks require energy, so a body with more muscle generally spends more energy at rest than it would with less muscle.
That effect is real, but it is not a dramatic calorie burn. Muscle uses energy at rest, yet it does not consume as much as it does during movement. Adding muscle therefore nudges resting energy needs upward; it does not turn the body into a furnace that burns off any amount of food.
Why the Difference Varies Between People
Resting energy use depends on more than muscle. Body size, age, genetics, and the proportions of muscle and other tissues all contribute. Fat tissue also requires energy to maintain, though generally less per pound than muscle. That helps explain why two people of the same weight can have different resting energy needs.
Men, on average, tend to carry more muscle, partly because testosterone supports muscle growth. The hormone is one influence, not a complete explanation: individuals vary, and training, nutrition, age, and other factors affect how much muscle someone has.
The practical consequence is gradual rather than instant. Building or preserving muscle can modestly raise the energy the body uses at rest, while its larger payoff is that muscle makes movement possible—and movement can use far more energy than muscle maintenance alone.
