by John Meadows T-Nation
Here's what you need to know...
When you bulk up and body fat rises, you gradually decrease insulin sensitivity, impeding muscle growth.
The more overweight you are, the more you change your physiology to favor fat storage over muscle growth.
Most people who bulk will store fat in just one area, like the belly or love handles, making it tougher and tougher to lean that area out.
Bulkers sometimes experience ectopic fat storage. Because the body is being flooded with excess calories, glucose, and triglycerides, it'll begin storing the excess not just in adipose tissue, but in the muscles themselves, giving a soft appearance to the muscles.
Most males don't need to get above 12% body fat to gain muscle optimally.
You need a calorie surplus to build muscle and it's extremely hard to eat just enough to build muscle without some fat gain. However, gaining five pounds of fat to gain one pound of muscle is a bad idea.
Back when I started training, guys would spend the off-season "bulking." The rules were simple: Eat every two to three hours and always eat until full. While "clean" foods like chicken and brown rice were the ideal, no one was docked points for sneaking in a pizza during the post workout "window of opportunity." As long as the number on the scale was growing, that was all that mattered. Scale weight became the metric by which you judged the success of a bulk.
It usually wasn't a pretty process. Let's say you decided to bulk up to 250 pounds by Christmas. Pants fitting tight at 235? That's why they make those blue stretch pants that Wal-Mart shoppers wear! Keep eating. Can't fit into your suits at 240? See if your boss will let you make every day casual Friday! Keep eating. Eventually you reach your goal. The scale says 250 pounds. You win.
But did you really win? You gained 30 or 40 or even 50 pounds in four or five months. You might have a bigger bench and squat not to mention chipmunk cheeks and a nice, tight, low back that barks even when you do a single rep of tying your shoelaces, but are you any better? I don't think so.
First, building muscle actual, contractile muscle tissue is a painstakingly slow process for any lifter past the beginner or newbie phase. For an experienced lifter, a gain of 1-2 pounds a month of pure muscle would be excellent. It adds up to 10 pounds or more in a single off-season. However, only a scant few bodybuilders can gain muscle at such a rate, and 10 pounds is a far cry from the 40 or 50 pounds you slapped on during your bulk.
Furthermore, when you bulk up and body fat levels rise, you can gradually decrease insulin sensitivity, which can actually impede muscle growth. Insulin is actually a signaling protein for both muscle and fat cells to utilize amino acids and glucose. Ideally, insulin-sensitive muscle cells will readily absorb glucose and amino acids when insulin "signals" them to open. With increased body fat, though, comes increased levels of insulin, and this can desensitize muscle cells to insulin's signaling effects.
If you decrease insulin sensitivity, your muscle won't use glucose and amino acids as efficiently, and since it's metabolically less expensive to store fat, your body will convert more of the excess calories into body fat. The more overweight you are, the more you change your physiology to favor fat storage over muscle recovery and growth.
This physiological phenomenon where protein synthesis is inhibited and fat storage is elevated is referred to as anabolic resistance, and it's the last thing you want as a bodybuilder. Subsequently, the further along you are in your off-season (i.e., the fatter you get), the more likely it is that any excess nutrients you eat are being stored in your butt and gut not your quads and biceps. And, the less likely it is that your training is leading to any actual muscle growth.
Of course, there are always outliers. I know guys who can gain 50-plus pounds in an off-season and just get bigger all around. At worst they'll lose their veins and maybe get chipmunk cheeks. Exceptions don't make rules however, and simply because the top guys can "get away" with a bulking strategy doesn't make it a sound option for the majority of us who are less genetically gifted.
Brand New Fat Cells, Accelerated Fat Storage
Another really troublesome aspect to bulking is that regular mortals will store most of their fat in just one unsightly area, like the belly or love handles. Not only is this extremely unhealthy (fat around the abdomen is directly correlated with heart disease and hypertension), it can lead to the creation of new fat cells that make it even harder to diet down once bulking ends. This process is called adipogenesis, and it occurs during periods of intense weight gain and calorie surplus.
When someone is doing heavy-duty bulking, the excess calories all get eventually converted to glucose, which is essentially sugar. Glucose gets used by both muscle and fat cells for energy usage and storage. When glucose levels are continuously high though, and you have more than you need for just your muscles, all that excess glucose will be stored as fat. This is why hard and fast "dirty" bulking rarely leads to large increases in muscle. Past a certain body fat point, you're simply accelerating fat storage.
Over time then, as bulking is repeated, you're actually fattening up the same parts of your body over and over again. This makes for a total bitch of a diet if it's already hard to whittle away at that one area, adding even more fat there means you should prepare for 12 weeks of hell. Even worse, the higher your body fat levels climb, the greater the possibility of it leading to anabolic resistance. Getting that stubborn area down will likely hurt other areas too, and actually make them appear emaciated. Consequently, it can negate any muscle gains.
To make matters worse, bulkers can experience another phenomenon known as ectopic fat storage. Because the body is being flooded with excess calories, glucose, and triglycerides, it'll begin storing the excess not just in adipose tissue, but in the muscles themselves. This is called intramuscular triglyceride storage. This is what often contributes to dirty bulkers having a soft appearance to their muscles.
It's not just cosmetic, though. This intramuscular fat can also inhibit protein synthesis and subsequent muscle growth. Everyone's likely seen the occasional bodybuilder that got huge in the off-season but somehow lost all his soft gains when he dieted back down, and ectopic fat storage is partially responsible for that happening.
Let's add another wrinkle. Getting fat over and over again can make getting leaner more difficult each time. If you get too fat and then have to kill yourself to diet down, the body will hang onto fat that much harder the next time you diet. This particular phenomenon is somewhat related to the metabolic damage concept of reducing basal metabolism over and over again to the point where weight loss is nearly impossible and weight gain can be caused by even the slightest of calorie surpluses.
While metabolic damage is often associated with female competitors, male bodybuilders can experience the same effects, but to a very different degree. Picture a male bodybuilder that bulks up to 300 in the offseason but has to diet down to 250 on stage. That's a 17% reduction in weight. Basal metabolism will begin to drop whenever there's a 10% reduction in weight, so this bodybuilder is going to be slowing his metabolism a bit as he diets.
If, however, he dirty bulked, he probably has to deal with anabolic resistance, too. If he repeats the dirty bulking process again post-contest, he's reinforcing the increased fat storage and anabolic resistance that he experienced before. This will make it harder and harder for him to diet for each contest, and each time he bulks up he'll be less and less likely to put on any new muscle. He might not be experiencing metabolic damage in the classical sense, but metabolically he's causing a lot of things to go wrong.
You Can't Get Away With It
All right, I hear you yelling. Bodybuilders have bulked up and cut down for shows for decades, and more than a few Mr. Olympias did it successfully as well. And you're not wrong. It would be silly to say the approach doesn't work because it clearly has. However, what you don't hear about are the thousands of guys who bulked up and got too fat, messed up their insulin sensitivity, and never really reached their true potential in either size or conditioning.
Consider also the guys that started out with a bang and looked amazing in one or two shows, but were never able to repeat that level of conditioning or fullness again and faded from the spotlight. Many of these guys beat me over the years and ended up doing nothing as pros, which always made me all that more irritated. Like I said before, what the absolute top guys do is often the result of what they can get away with because of their genetics. It's not necessarily a model for everyone else to follow. If you want competitive longevity, you have to take a more thorough and thought-out approach.
So the decision to bulk up or not bulk up boils down to knowing your body. You need a calorie surplus to build muscle, and it's hard to eat just enough to build muscle without some fat gain. However, gaining five pounds of fat to gain one pound of muscle is a bad idea. As I've shown, you're more likely to lose that pound of muscle because of trying to diet that five pounds of fat off.
The Bottom Line
I don't see any reason for most guys to get above 12% body fat. Personally, I prefer to stay under 10%. Ultimately, it will depend on where you start to lose insulin sensitivity you'll know you're there as pumps will decrease and your muscles will start looking soft. If that happens, take it as a sign to end your bulk.