Answer
"Fats have a glucose-sparing effect as well as a protein-sparing effect."
In lipolysis fats are broken down into glycerol and fatty acids. The body preferentially oxidizes the fatty acids as a source of energy thus reserving the glycerol to be catabolized to provide glucose for the cells, neurons and RBCs, that use glucose exclusively as their energy source. Lipolysis is triggered by glucagon and epinephrine when glycogen stores are depleted about 30%. Skeletal muscle fibers make extensive use of fatty acids as an energy fuel.
Work Step by Step
As long as enough fat is available to supply the energy needs of tissues, protein is not catabolized for fuel. Rather, the protein is reserved for other purposes; for example, tissue repair, antibody production, and enzyme synthesis, This is known as the protein sparing effect of lipids.
