Omnivore mammals play a crucial role in maintaining food web structure and stability in ecosystem. However, on the molecular level, their dietary habit remain inadequately revealed, mainly because existing studies focused separately on animal or plant food sequences (amplified the sequences of animal food or plant food respectively), failing to and being unable to achieve the unified quantification. To address this bottleneck gap, we proposed a new method that utilizes the combination of two pairs of primers to amplifying the fragments of nuclear 18S rRNA gene and mitochondrial 12S rRNA gene. The method can quantify both animal and plant food sequences in a unified manner, thus revealing whether omnivores are more vegetarian or carnivorous. Simultaneously optimized dietary indicators at the individual level helps to exclude the DNA sequences of the omnivore itself, eliminating the need for blocking primers. Our case study, based on the wild Asian badgers (Meles leucurus), demonstrates that method effectively achieves unified quantification of diverse food sequences. Overall, our method provides a viable new insight into the quantitative study of molecular dietary habits in omnivores. We advocate abandoning stereotypes and extending this method to animals traditionally considered as herbivores or carnivores. We also highly encourage further efforts to achieve unity between animal and plant food in the dietary habit studies of omnivores and other animals.