A new study on cannibalism reveals that humans aren’t all that nutritionally valuable. Compared to one dead mammoth, which can feed 25 hungry Neanderthals for a month, cannibalizing a human would provide the group with only about a third of the calories needed for that day, reports National Geographic.

Humans have engaged in cannibalism throughout history, but understanding exactly why is up for debate. Well, to better understand the reasons behind it, James Cole, a senior lecturer in archaeology at the University of Brighton in England, counted the calorie content of all edible parts of the human body using autopsy data. He found that an adult man is worth 125,823 calories, with 32,376 calories from his lean muscle. The thighs are among the most nutritious parts providing 13,354 calories, Time reports. The upper arms offer about 7,451 calories; the brain and spinal cord 2,706, the liver 2,570 and the heart just 651.

Reporting in the journal Scientific Reports, James Cole says that on a nutritional level, humans fall where expected, in terms of calorie content, when compared to animals of a similar body weight. However, when compared to large animals often found in association with anthropogenically modified human remains, the calorie returns of individuals and groups of hominins are significantly less than individual large fauna commonly exploited by our ancestors in the past. Humans may have been seen as another source of food and were cannibalized on an opportunistic basis, the paper notes.

Reference: Assessing the calorific significance of episodes of human cannibalism in the Palaeolithic. Scientific Reports, 2017. DOI: 10.1038/srep44707