Beyond its role in building muscle, protein may have beneficial effects on our metabolism. One study found that giving elderly people supplements containing essential amino acids (that is, mimicking some effects of increasing dietary protein) lowered their levels of liver fat and circulating triglycerides.

the reason is this: your liver makes cholesterol as a raw material for the bile salts that help you digest fat, so if you aren’t eating much fat, your genes will be given the signal to down-regulate cholesterol production.