A recent study reported in the Journal of the American MedicalAssociation (JAMA) found that weight loss is more successful long term when a person gets monthly help and support from a nutrition counselor.
This can be as little as a 10 -15 minute phone conversation! Just enough to just keep you on the right track.
Bottom line...don't go it alone! Yes it may cost you alittle to get professional guidance, but wouldn't you rather keep the weight off than re-gain it again?
That sounds cheaper in the long run to me!
You can read the original study in JAMA here, or a summary article in USA Today here.
That's one thing I like about groups like Weight Watchers and TOPS. You feel more accountable and stick to the plan better. After you reach your goal weight you should definitely go back monthly for a weigh-in to keep yourself on the straight and narrow.