Fatty acid synthesis occurs in the cytosol. Acetyl CoA units are transported to the cytosol via citrate for this process to occur. Fatty acid synthesis starts with the formation of malonyl CoA from acetyl CoA by the action of acetyl CoA carboxylase. This process ends when the chain length reaches 16. Fatty acid synthesis occurs in liver, mammary and adipose tissues.
Body fat reflects dietary fat for non-ruminants.
However, this is not the case for ruminants due to hydrogenation by rumen microbes.