Researchers can look at isotopes in hair and bone samples to see whether people were vegetarians or omnivores. They can also see investigate resides left in clay pots and other tools which can indicate, for example, the presence of milk or other uses of food.
Now, new details found on a mummy by the name of Otzi, revealed that Otzi ate meat shortly after before his death specifically red deer and ibex as well as whole wheat seeds, but no milk and cheese were evident as the last diet.
Additionally, scientists believe that Otzi might have used charcoal to help dry out the meat by using a bit of heat.
Overall, they believe that Otzi’s diet included a mix of protein, fat, and carbs as well as plenty of essential nutrients.