GM soy burger with salad vegetables and bread. The burger has been made using genetically modified (GM) soya. Soya beans (Glycine max) are one of the best dietary sources of protein, also providing minerals and B-complex vitamins. GM soya has had a gene altered to make it resistant to chemical herbicides. This allows farmers to spray entire crops with herbicides to kill weeds, theoretically increasing soya yields. There is concern over the safety of GM food.