One key to weight loss is water.
Drink a lot of water, and you will lose weight.
I drink three 16 oz. bottles each day at the office. Plus, an 8 oz glass in the morning and another 8 oz glass at night. that's how I get my 8 glasses a day in.
Since I've started drinking primarily water in place of diet coke, I've noticed a big change.
It's not the only key, but drinking water has helped me lose weight.