Why do you retain water and how can you avoid it?

Many possibilities: Too much salt (sodium) in your diet can cause you to retain water. Therefore, paying closer attention to what you eat can help. Just beware of hidden sodium/salt in lots of daily foods that don't necessarily taste salty. On the other hand, you can retain water due to heart failure and/or kidney failure. Liver failure can also do this. Less serious but still a problem is venous insufficiency.