You are not alone, I’m trying to cut 3 kg, too. But dieting on the bike is a bad idea, because (to quote Frank Overton from FasCat Coaching) 80 % of the dieting is off the bike. In my experience, it is much easier to have a steady, maintainable calorie deficit when I fuel all of my rides.
Believe me, I understand your logic perfectly. In the past, I was you! I did what you are proposing here in the past, thinking it’d make me a better cyclist, too. And it did not work as well as fueling properly. My FTP (absolute and specific) was about 12 % lower and I was often ravenous after hard workouts. I was so hungry, I ate half a loaf of bread. Especially during rest weeks and in the beginning of the off-season I’d gain weight, because it’d take my body 1–2 weeks to adjust to my changed calorie expenditure. Now my breakfast after training is more or less the same no matter what kind of workout I have. In fact, I have a full stomach already, so my appetite is moderate.
If you want more infor, have a look at the thread that I linked to earlier as it addressed weight loss and fueling specifically: the overwhelming consensus is that you should not cut calories while on the bike if you want to lose weight.