Chinese have been experiencing dramatic changes in their body weight in the last ten years. Food service sector is believed to have significant effect on the rise of obesity in China. This paper analyses Body Mass Index (BMI) and overweight issue of adults 18 years and above in urban China with respect to food eating locations and other socio-economic and demographic variables. The data are from household surveys in three representative Chinese cities: Xi’an, Shenyang, and Xiamen. OLS is used to estimate the relationship between continuous BMI and food eating outlets, and an ordered probit model is fit to the categorical BMI. Findings indicate that the number of meals eaten at cafeterias significantly increases the probability of being overweight and obese while decreasing the probability of staying underweight and normal. The probability that a person in Xi’an, Shenyang and Xiamen is underweight and normal decreases by 0.25 and 0.49 percentage point respectively if consuming one additional meal at a cafeteria. And one unit increase in the number of meals ate at a cafeteria increases the probability to become overweight and obese by 0.55 and 0.19 percentage point correspondingly. The number of meals consumed at full service restaurants and fast food outlets are found to be insignificant on the body weight of Chinese adults. Education, household income and employment status all have significant effects on body weight change, as well as smoking status and physical activity.