You can't really digest plant nutrients regardless of the nutritional dogma pressed out in the dietary religions. This is due to your lack of cellulase, an enzyme critical for breaking down cellulose in plant cell walls. The human digestive system struggles to extract nutrients of any type from plant fibers, leaving most plant material unprocessed.
While some types of gut microbes help slightly, they can't compensate for the significant enzyme deficiency. Your body's nutritional design fundamentally requires animal fats and proteins for energy, complete amino acid profiles, and essential nutrients. Curious about your biological nutrition blueprint?