<P> Starvation mode is a state in which the body responds to prolonged periods of low energy intake . During short periods of energy abstinence , the human body burns primarily free fatty acids from body fat stores , along with small amounts of muscle tissue to provide required glucose for the brain . After prolonged periods of starvation the body has depleted its body fat and begins to burn primarily lean tissue and muscle as a fuel source . </P>
where does body get energy from when fasting
primarily free fatty acids from body fat stores small amounts of muscle tissue