One of the most common statements I hear is, "I want to lose ___lbs in ___weeks/months". I wish it was that simple. Sometimes people are able to achieve these goals, and sometimes they aren't. The question is: can they maintain their goal? If you really want long term results, it requires establishing habits not goals. Habits that include your diet, exercise, sleep, hydration, and stress management.
So, when people come to me with numbers of pounds and numbers of weeks, I usually tell them that there is a possibility of them reaching their goals. However, there's a greater possibility of them changing their life in a way that they will never be the same again.