If you read fitness magazines you may get frustrated if you follow the advice exactly and gain weight. What you may find is that the information isn't always accurate and unless you are spending 4 hours a day in the gym chances are you can't burn that many calories. Using reason and wisdom to match your fitness needs is important for future success.
First, much of this advice is for really think guys that want to bulk up. They don't process calories the same and have higher metabolizes. They need all these calories to leave some for building muscle.
No doubt building muscle requires a certain amount of high protein and beneficial nutrients. The difference is that if you go too high in those areas it converts to fat quickly.
For bigger guys that can either be muscled or chubby they should eat what they are required to eat but make better choices over their food. Watch themselves for a week and decide whether they need more or less calories.
Lets say they are gaining weight much faster than it is to make the 1.5 lbs of muscle a month. This will either be water weight or fat. Waiting a week to make a decision will help ferret it out.
If you are gaining more pounds you may either adjust their type of food you eat and the calorie amount. They should stay about the same to gain muscle and reduce fat. If they are trying to loose fat they may need to adjust their workout or eating style; but mostly their calories.
Making better choices will help you adjust calories through better eating. That is always the goal. However, anything over what you need will force your body to gain fat. Don't be afraid to pull back on the calories to 300+ under your needs to see if you start to loose again. Much of fitness is about the quality of the food and the amount of food you eat.
I am a certified fitness trainer so if you are in Escanaba or San Diego get in touch with me. firstname.lastname@example.org