I've been bodybuilding for 7 years now and what you're saying is not true. If you want to lose weight in a short time consider doing
HIT training. I'm the kind of person that has a really hard time gaining weight and it took me well over a year to create a diet that was right for me, a diet that allowed me to gain weight fast while maintaining the muscle building rate i was used to.
Once i got to a good weight i had to tone it down. Losing weight is easy, losing the correct weight (Fat, and not muscle) is another story. HIT training allowed me to do this in a good pase. I had 5% body fat at one point but the ability to maintain is was rather difficult for me whilst trying to put on a good amount of muscle so i stopped losing weight and started gaining again (never above 17% bodyfat, however).
On another note, your body adapts to what you eat. To keep a long story short, once you reach that point where you're eating bad food (read: more calories that you use / fat food) your body adapts to it and is able to slow your metabolism, therefor gaining weight quicker and it takes a long time (weeks to months) for your body to change this.
Adapt your diet, eat less calories and eat healthy calories. The fact that you don't have time is bullshit, you're on the internet right now and i'm sure you have 30 minutes of spare time a day to work out. Use those 30 minutes for HIT training, yes you'll most likely throw up a few times and you'll wake up with muscle pain in the beginning but you get used to it. Losing weight without workout out.... that's like walking from England to China when you can take a plane, it takes that much longer.