A phenomenological model for the synthesis of few-layer graphene (FLG) nanosheets by the method of self-propagating high-temperature synthesis (SHS) from starch, lignin, and other biopolymers is considered. We suggested that polysaccharides, in particular starch, could be an acceptable source of native cycles for the SHS process. The carbonization of biopolymers under the conditions of the SHS process was chosen as the basic method of synthesis. Chemical reactions, under the conditions of the SHS process, proceed according to a specific mechanism of nonisothermal branched-chain processes, which are characterized by the joint action of two fundamentally different process-accelerating factors – avalanche reproduction of active intermediate particles and self-heating. It is shown that the proposed model can explain the production of few-layer graphene nanosheets with linear dimensions of tens of microns and a thickness of several graphene layers.