Be consistent for at least 3 weeks. It takes about that long for new habits for be formed and if you tell yourself "it's only 3 weeks" you'll feel so amazing when the 3 weeks is up chances are you won't go back to old habits. Be sure to control portion size of meals, and incorporate fibre and protein rich foods which will help you to feel full.
It makes a lot of sense to first deal with what took you to the top before beginning your journey down that up-escalator. Clearly, simply jumping on that escalator without first dealing with the underlying problem will make losing weight and keeping it off so much more difficult -- remember, running down the escalator with no baggage is already hard enough.
One of the games I used to play as a kid was to run down the up escalator. To get to the bottom, I had to run down faster than the escalator was moving upwards. If I ran any slower, the escalator would take me back to the top. I use this analogy with my patients to help them understand the incredible challenge of losing weight and keeping it off.
To succeed in the fast-paced world we live in today, wasting time is not an option. Time can neither be bought nor replaced and taking advantage of each moment is crucial. Though many people may only have time to visit a gym 3-4 times per week for an hour, it is how they make use of that time that matters!