When it comes to performance I would have to rank nutrition right up there in importance with rest/recovery & training regiment. The fact is nutrition is as much of a behavioral response to one's environment as it is a conscious decision to begin to make more healthy dietary choices. Everyone's weight is going to fluctuate but the goal is to stay within 5-8 lbs of your ideal racing weight. I believe there are so many factors that come into play when attempting to do this that just saying "make proper dietary choices." is a bit like saying "train hard". What does that actually mean?
Making proper dietary choices is based on the individual. Nine times out of ten, you know what it is you are doing that is preventing you from being at a weight you feel comfortable with. I have found that most individuals make very healthy choices throughout 95% of the day but then make one or two very unhealthy choices during the remaining 5%. These one or two unhealthy choices seem to come at the end of the day for most....when they have extra time on their hands and are able to relax.
Once you identify what those one or two poor decisions are, do your best to set yourself up for success during those times. Avoid buying those foods in the first place. Be more mindfull of when it is you are making poor dietary choices. Surround yourself with those that make healthy choices at work and during social events. The list goes on and on. The real solution is to sit down and honestly identify those one or two poor choices you are making and then set out to minimize this behavior. It is not easy since this behavior is usually serving a purpose and in most cases it is not nutritional in origin. Many times we eat mindlessly in order to comfort ourselves or reduce anxiety. It helps to think of food as fuel rather than comfort. If you are thinking of food as comfort it helps to identify other ways to comfort yourself though activity (reading/music/learning a new skill....).