Neanderthals have been commonly depicted as top predators who met their nutritional needs by focusing entirely on meat. This information mostly derives from faunal assemblage analyses and stable isotope studies: methods that tend to underestimate plant consumption and overestimate the intake of animal proteins. Several studies in fact demonstrate that there is a physiological limit to the amount of animal proteins that can be consumed: exceeding these values causes protein toxicity that can be particularly dangerous to pregnant women and newborns. Consequently, to avoid food poisoning from meat-based diets, Neanderthals must have incorporated alternative food sources in their daily diets, including plant materials as well. In this manuscript, we review traditional as well as more recent approaches for reconstructing the diet in past human populations, and we show how new archaeological discoveries and innovative methods are changing our views of Neanderthal ecology and behavior. We further underline the importance of reconstructing Neanderthal environments derived from palaeoecological data to better understand and interpret the dietary evidence obtained by these methods. Finally, since the intake of specific foods can be invisible to certain techniques and detect by others, we suggest using a more holistic approach by integrating the findings of more than one method. Such comprehensive analyses would enable the reconstruction of the whole dietary spectrum, which is particularly important for species like Neanderthal, who lived under severe and unstable climatic conditions. Neanderthals are undoubtedly the most studied and best-known group in the human fossil record. Despite that, for more than 100 years since their discovery, research on Neanderthal ecology, subsistence strategies, and diet have received remarkably little attention (Ready, 2010). It is only with the emergence of new archeological disciplines and development of innovative analytical approaches in the 1960s, that scholars began to look at Neanderthal behavior and adaptations to their environment. Methods such as faunal analysis, lithic technology, and taphonomic studies progressively led to a general portrait that defined Neanderthals as a homogenous group, with similar nutritional needs typified by a reliance on the consumption of terrestrial animals. This idea was reinforced by the study of stable isotopes and Neanderthal anatomy. The general robusticity of Neanderthal skeletons, with relatively short limbs and heavy trunks, has been interpreted as adaptation to cold stress environments that follow the ecogeographic principles of Bergmann's and Allen's rules (e.g., Trinkaus,