For me, I gain weight with heavy exercise. It's the old adage that "you work up an appetite". I have to be very careful with my exercise levels or I will derail weight loss efforts. At the end of the day, weight loss is about what you put in your mouth.
I am not talking heavy, I am talking LONG. In fact at the beginning of the season, during base training, the computer should show: Anaerobic effect: 0. These 300 km/week you can do with only 1000 meters or even less up, depending where you live.
It is almost impossible to outeat this sort of activity, you will have neither the time nor the desire to eat a lot if you do this.
But again, it is imperative that you do it no matter what. You feel good-you do it, feel bad or lazy-you do it all the same. And then what type of food you eat wont matter one bit.
Heavy anaerobic exercise is a proven way of gaining weight, I end every skiing season quite a lot heavier than I start at. This year I am extremely happy to have gained only 4 kg, there were years this was between 10-15 kilos.
These 4 will be a distant memory just 3 weeks into the cycling season.
Road cycling keeps your weight in check like nothing else.