A recent study has revealed that children who continue to consume fluids up until the age of 2 have a 30% higher chance of becoming obese when they start school.  

http://www.bbc.co.uk/news/health-13294632

The BBC reportes about a US study that revealed this information. 

Essentially, this is very logical. Most bottles hold at least 8 fl. oz. Most children still drinking from a bottle, at the age of 2, consume sugary forumla or homo milk, and they consume a full bottle at a time. This is great, however, they are also eating solids and probably have a healthy appetite. There are a lot more calories being consumed than necessary. 

Take a look at what your toddler is consuming and how. Understanding that bottles provide confort to a child, consider replacing the fluid with water or tea, and then consider weening them. This can help reduce the risk of obesity. It will also help with not having to get braces from their teeth not forming correctly - maybe the orthedontist won't thank you, but your wallet will.