No, you don't have to gain a ton of fat to build muscle, but you do need to be realistic. Here's a little reality check.
Get Ripped, Then Get Realistic
Sure, you look your best when you're lean. After that first successful diet, every lifter feels like a god. They're itching for any excuse to take their shirt off and display their six-pack.
Once you've gotten really lean it changes your perception of what good shape is. Being shredded is intoxicating and you want it to last forever. The problem is it can't. Well, not if you want to add a noticeable amount of muscle to your frame.
Mythical Lean Gains
After dieting down that first time, most lifters make the mistake of thinking they can just pack on muscle while staying shredded. Unfortunately, those mythical lean gains are exactly that – a myth. If you chase these lean gains then you'll end up spinning your wheels, gaining little-to-no size.
Are you happy to retain a lean, but only vaguely muscular physique? Cool. The lean gains approach might suit you. Want to be big and ripped? Then you need to take a smarter approach.
Caloric Surplus: You Need It
If you want to pack on a considerable amount of size then you need a sustained calorie surplus – eating above your maintenance level of intake. With this comes an increase in scale weight, muscle mass, and a little fat. There's no avoiding it. After the newbie gains have run their course you simply can't add slabs of muscle without some fat gain.
You don't have to get fat and sloppy, but you must accept that some fat will be accumulated along the way. The key is to keep the ratio of muscle to fat as high as possible. If you do this, then when you diet next time around you'll look far better.
This is why a phasic, or cyclic, approach to your training and nutrition is best – periods dedicated to gaining muscle or losing fat. During your bulk you won't look so good with your shirt off, but you will look bigger in a T-shirt. So, plan accordingly, bulk during the winter months and diet when summer is on the horizon.
Done right, this strategy can dramatically change your physique. It takes time, effort and consistency, but patience is a muscle-building virtue, and if you follow this plan you'll temporarily look worse to eventually look way better!