Maybe. I've actually implemented a rather complex set of rules to maintain my weight and it has been working so far. I keep a rough estimate of the calorie intake every day and try to keep it within reasonable bounds. I do make exceptions (hey I still love eating 2 pounds of steak with 3 pints of beer), but those days are followed by heavy dieting days to bring the calorie balance back. I also have a high-watermark/low-watermark system for my weight, so in case it runs away (like during holidays or trips), I am still 1.5-2.5 weeks away from reaching my normal weight.
I'll level with you: the easiest part for me so far was the initial weight loss. I got down to 15lbs less than I am now and it was much easier than it has been since. It's like my body adjusted and got much more conservative but it took a year or two. Maybe that won't be true in your case, but give it time before you make an assessment about the difficulty.
