给定一个英文段落，要求生成一个总结性的主题句。
"There are several factors that contribute to the rise of obesity rates in modern societies. Firstly, the prevalence of fast food and convenience foods that are high in calories and low in nutrition are widely available. Secondly, the sedentary lifestyle created by modern technologies, such as television and video games, leads to a lack of physical activity. Finally, the stress of modern life can lead to emotional eating and unhealthy habits."
The rise of obesity rates in modern societies can be attributed to factors such as the availability of fast food and convenience foods, sedentary lifestyles, and stress.