In a word, no! Common practice in bodybuilding circles is to spend part of the year consuming more calories, allowing for fat gain, while training heavy in an effort to increase muscle volume. Then, diet strictly to get lean. Without a doubt, this is unnecessary (and I’ve even tried it before).
While I don’t deny that growth is a calorie-intensive process, so is fat gain. Any “size” you gain while overeating, will come with fat. And when the fat has to be taken off to get lean (unless you’re a strongman or powerlifter, then you can stay fat for life) you will also have to undergo a period of low calories, during which growth will be compromised. So you end up with the same net calorie balance, you just spent half of the year or more (depending on your competitive schedule) being fat.
Let’s say a bodybuilder coming off a contest has a metabolic requirement of 2000 calories. He/she can either:
a) Eat 3000 calories for three months in an effort to “bulk up” and gain muscle (and fat), but then will have to eat 1000 calories for another three months to drop the fat off. Net calories = 2000 for six months.
b) Or, bodybuilder can stay at 2000 calories for six months. No fat is gained, therefore no fat needs to be lost. Net calories = 2000 for six months.
The difference is that in example b) there was no dreaded “fat” period, and no need to severely lower calories to get lean again and deal with the mental adjustment of changing dietary habits.
Fat and muscle are separate tissues, so treat them as such. Adjust your calories based on your body fat levels, and let training dictate your muscle size. You will eventually reach your genetic potential, and look great no matter what time of the year.
Unless you just started lifting or are using pharmaceutical enhancement, the amount of actual muscle (contractile protein) you can gain is not much. You should be more concerned with muscle “fullness” than the gross amount of “weight” you can gain from training. However, 1-2 pounds of pure muscle in all the right areas on a lean physique looks tremendous.