Refraining from eating grain or breatharianism is a method to achieve fasting by derivation and/or taking Daoist pills

which has the effect of health preservation

eliminating disease and prolonging life. Compared with therapies of European fasting and calorie restriction

this method has its unique advantages. Present relating researches of refraining from eating grain have problems of vague definition

unclear connotation and confused methods

which limits its orderly development. Based on these

the authors outline the history of refraining from eating grain

put forward the basic concepts

point out that the connotation includes two parts（ derivation and/or taking Daoist pills）

as well as summarize the methods of refraining from eating grain. Meanwhile

the authors analyze the progress and deficiencies of refraining from eating grain researches. Based on this

the authors propose the mechanistic hypothesis "Heng Yuan Lun（ theory of maintaining balance and fundamental order） "of refraining from eating grain to improve the level of Chinese medicine refraining from eating grain research and lay the foundation for further mining its medical application value.