Stable isotope analysis allows researchers to identify isotopic markers of certain foods in human bone and teeth, which can be used to reconstruct ancient diet and population movements.
For example, in the Southwest, scientists use the ratios of different carbon isotopes in human bone to estimate the relative contributions of domesticated corn and wild plants to the ancient diet at different times throughout history. Such studies have shown that people in the Four Corners area became dependent on corn by about 500 B.C.To reconstruct population movements, scientists look at the element strontium. Plants and water contain varying relative quantities of two different strontium isotopes, depending on the geology of the local area. Strontium is absorbed into human tooth enamel and bone through the consumption of food and water. Because tooth enamel forms in early childhood and is never replaced, it preserves a strontium record of where an individual lived early in life. Bone is different. In a process called "remodeling," old bone cells are continually replaced by new ones, with each generation of cells acquiring the strontium signature of the region where an individual was living at the time. Thus, bone preserves a record of where a person lived late in life. By comparing tooth and bone chemical profiles, archaeologists can tell whether that person lived in the same area his or her entire life or moved from one area to another.
. . . about stable isotope analysis and reconstruction of diet (Wikipedia).
Read about a study in the American Southwest that used stable isotope analysis to reconstruct ancient Pueblo diet (research paper available through Academia.edu).
Read about a study in the American Southwest that used stable isotope analysis to reconstruct ancient population movements (Archaeology Magazine online).