Caffeine content varies by soda. Most sodas contain between 10-60mg of caffeine. Energy drinks contain more than twice this amount. Ritz cola has a particularly low caffeine content at 10.3mg, while Pepsi One has 57.1mg. Though Mountain Dew is notorious for having a lot of caffeine, it only contains 55mg. In comparison, a single cup of coffee has 95mg of caffeine. Caffeine stimulates the central nervous system, which is why it's a popular choice when people are feeling tired and sluggish. Caffeine makes some people feel alert and energetic. Caffeine can also help with headaches and migraines. However, too much caffeine can cause anxiety, insomnia, and an upset stomach. If you'd like to limit your caffeine intake, consider choosing caffeine-free soda.