1. Introduction:In Hong Kong the obesity problem is quite serious. According to the Population Health Survey 2003/2004 commissioned by the Department of Health, around 18% of the population aged 15 years and over were overweight and around a quarter of the population was obese. [1] Nonetheless, to address the problem effectively, the causes of the problem will be evaluated in this report and various preventive measures will be suggested.2. Main reasons for obesity in Hong Kong:2.1. Nutrition: There are many working women these days. They have to sacrifice their time cooking in order to work. Therefore, they prefer to choose fast foods as their meal because these foods are generally cheap, tasty and widely available. But these foods are generally high in energy and low in nutrients. [1] For example, an average fast food meal provides 1,000 to 2,000 kilocalories, which is the recommended daily calorie intake for adults. [1] In the long term, persistent intake of these foods at every meal can lead to obesity.2.2. Physical activity: Hong Kong has a well-developed transportation network. People can go anywhere conveniently by taking public transportation or driving private cars. At home, many people nowadays engage in more sedentary activities such as watching TV. Due to the prevalence of public transportation and the increase in sedentary recreational activities, opportunities for people to exercise are decreasing. It is estimated that approximately 17% of adults do not engage in physical activity. [1] One study stated that there is an inverse relationship between BMI and physical activity. [2]2.3. Busy lifestyle: Hong Kong is a prosperous yet busy city. Most people living in Hong Kong have a busy lifestyle. They have to work around the clock despite having less time to rest. According to a survey published in the International Journal of Obesity, people who sleep less than six hours and work more than 9 hours have the highest BMI. [2] This shows that reduced sleep hours and long working hours could be the factors leading to obesity.3. Preventive measures that can be taken:3.1. DietPeople usually mistakenly believe that to stay fit they need to eat less. Some of them may choose to skip breakfast, but this is not correct. Breakfast is essential [3] as it provides nutrients for the entire day. Additionally, people should limit their intake of high-calorie foods and high-fat foods.