Sea fish consumption appears as an important factor in both stepwise MLR and GWR. The consumption of sea fish, kelp, seaweed, jellyfish, mussels, and other sea foods are excellent sources of protein and unsaturated fatty acids. They also supply inorganic salts, which hinder the absorption of cholesterol in the intestines, all of which are associated with healthy diets. Almost all the cities along the coast, whether developed or poor, had high longevity ratios. Although some coastal cities in China are richer, one-third of them remain below the average gross domestic product (GDP) for all cites in China, including Huludao, Dandong, Jinzhou, Yingkou in Liaoning province, Shanwei, Jieyang, Chaozhou, Zhanjiang, Shantou, Maoming in Guangdong province. A relatively low longevity ratio was found in the coastal regions of Hebei province, where the production of sea fishing was also lowest among the coastal regions. In Guangdong province, the longevity ratio gradually decreases moving inland from coastal regions, as illustrated in Figure 17.