Dirty Bulk vs. Clean Bulk: What’s Best for Building Muscle?

Many fitness buffs know there are two approaches to bulking: ”dirty bulking” and “clean bulking.” However, fewer know which is best for building muscle.

Dirty bulking is the easier, more enjoyable strategy that helps you rapidly gain size. The drawback is that much of the weight you gain while dirty bulking is fat, not muscle. 

In contrast, clean bulking requires meticulous attention to your diet and delivers much slower weight gain. The advantage is that most of the weight you gain while clean bulking is muscle, not fat.

On the other hand, clean bulking requires precision and won’t help you bulk up as quickly. The benefit, however, is that most of your newly gained size will be muscle, not fat.

In this article, we’ll dig into the difference between dirty bulking vs. clean bulking to help you determine which approach will work best for you.

What Is Bulking?

Bulking is a method of dieting that involves temporarily eating more calories than you burn (a “calorie surplus”) to maximize the muscle and strength you can gain.

Bulking is necessary because the number of calories you eat affects muscle growth—your body’s “muscle-building machinery” runs best when energy (calories) is abundant, so if you don’t eat enough calories every day, you’ll struggle to get bigger and stronger.

Types of Bulking: Clean vs. Dirty Bulking

For most people, there are two approaches to bulking:

1. Dirty bulking
2. Clean bulking

That said, this distinction is relatively recent—before the early 2010s,  bodybuilders typically didn’t differentiate between the two. Traditionally, “bulking” just involved eating more food, with little nuance beyond the sheer increase in calories.

However, this changed when the “evidence-based fitness community” began to highlight and communicate the importance of how daily calorie intake affects muscle growth, which helped to make the concepts of dirty and clean bulking more mainstream.

What Is a Dirty Bulk?

Dirty bulking involves gaining weight as quickly as possible by eating as much food as you can stomach, regardless of its calorie content or macronutrient value (hence why some call it the “see food” diet). 

People following a dirty bulking diet will also often consume foods with poor nutritional value, provided they’re high in calories. For example, common dirty bulk foods include hamburgers, pizza, pastries, ice cream, doughnuts, and candy.

What Is a Clean Bulk?

Clean bulking involves regulating the number of calories and the type of foods you eat so that most of the weight you gain is muscle, not fat.

As a result, you gain weight and strength slower than on a dirty bulk, but a much larger percentage of the weight you gain is muscle instead of fat.

While clean bulking, people tend to eat nutritious foods that benefit overall health, such as lean meats, fruit, vegetables, and whole grains. 

Because these foods tend to be lower in calories than the fare consumed on a dirty bulking diet, clean “bulkers” also usually eat plenty of healthy fats, including avocado, olive oil, and nuts and seeds, and enjoy occasional “treat meals.”

What Is a “Lean Bulk” Compared to a “Clean Bulk?”

For most, “clean bulking” and “lean bulking” are synonymous: both refer to a diet that prioritizes minimal fat gain while increasing muscle mass.

Some more “meticulous” dieters draw a distinction, though. They argue that clean bulking strictly involves eating only “clean” foods, which, they say, are unprocessed, nutrient-dense foods such as fruits, vegetables, whole grains, and lean proteins.

On the other hand, lean bulking focuses on gaining muscle with minimal fat but allows for more flexibility in food choices. This approach might include some processed (“unclean”) foods, as long as they fit within your daily calorie and macro targets.

Dirty Bulk vs. Clean Bulk: Which Is Best for Building Muscle?

When faced with the option of dirty bulking vs clean bulking, most new weightlifters (especially young guys) opt for “dirty” bulking. They do this for various reasons, but the most common drivers are:

• Dirty bulking requires less precision and discipline than clean bulking.
• Dirty bulking allows you to eat as much food as you like with no restrictions on the types of food or number of calories you consume, so you can go hog wild at meal times.
• Online fitness “authorities” often claim dirty bulking is the best way to bulk up fast.

In other words, dirty bulking is easier, more enjoyable, and seems like a good idea if you want to gain size as quickly as possible. 

It also appeals to those who feel weak after a long cut and are desperate to begin eating more liberally again. 

The problem is that dirty bulking inevitably leads to rampant overeating and fat gain.

No matter how much you eat, your body can only gain muscle so fast—you can’t force your muscles to grow faster by eating more calories. Instead, the extra calories are simply stored as body fat. 

Many people who follow this approach believe they’re gaining lots of muscle, but in reality, they often gain much more body fat than lean mass.

While some people brush this problem aside, justifying it with claims like, “You can always diet off the fat later,” or, “I want bulky muscle, not lean muscle” (more on this fallacy soon), it’s a mistake for several reasons.

As I explain in my fitness book for men, Bigger Leaner Stronger:

Overeating too often when lean gaining causes you to gain fat too quickly, forcing you to start a cutting phase earlier than you’d like, before you were able to gain much muscle or strength. This mistake particularly impedes more experienced weightlifters who can’t gain size or strength when cutting and need to spend at least six-to-nine months of the year lean gaining to make significant improvements in their body—an impossible task if they don’t control their eating.

What’s more, gaining fat too quickly can cause motivation to wane (the process becomes less fun when your abs are replaced by flab) and may impair insulin sensitivity, making building muscle and burning fat more difficult.

In other words, dirty bulking causes you to gain more fat than is necessary without resulting in extra muscle gain and alters your physiology in ways that make achieving your long-term body composition goals more difficult.

Thus, the smarter option is to clean bulk.

When you follow a clean bulking diet, you cap your calorie surplus at 5-to-10% more calories than you burn.

Research shows this is the “sweet spot” for supporting muscle growth while minimizing fat gain. Eating more than this will only cause you to gain more fat, not muscle.

And if you want to learn more about the perfect way to clean bulk, check out this article:

How to Lean Bulk Properly

Lean Muscle vs. Bulky Muscle: Is There a Difference?

Many people choose to dirty bulk because they believe it will help them build “bulkier muscle” than if they clean bulk. 

That is, they believe dirty bulking produces larger, denser, and fuller muscles, whereas clean bulking produces more defined but flatter muscles. 

While it’s true that your body will look different depending on whether you dirty or clean bulk, it’s not because the muscle is fundamentally different.

In most cases, you look bulkier after dirty bulking because your muscles are covered in more fat than if you clean bulk. It may also be because you retain more water when following a typical, high-carb, high-salt dirty bulking diet.

These factors can make your muscles look plumper, but they may also obscure your muscle definition to the extent that it resembles fat more than muscle. Dirty bulkers, for example, might develop “man boobs” rather than well-defined pecs.

Of course, how you want your body to look is up to you. If you want defined, visible muscle, clean bulking is the best solution. If you prefer a “puffier” look, dirty bulking may be more fitting. Just understand, in either case, the muscle itself is the same—it’s the fat coverage and water retention that differ.

Dirty Bulking vs. Clean Bulking: FAQs

FAQ #1: Will dirty bulking build muscle?

Yes, dirty bulking will help you build muscle. But because most people overeat when dirty bulking, it will also cause excessive fat gain. If you want to avoid this, clean bulking is a better solution.

FAQ #2: How long should you dirty bulk?

The duration of a dirty bulk can vary depending on your goals and how much fat you’re willing to gain. However, because dirty bulking often leads to significant fat gain, most people give up after a few months. 

FAQ #3: Should I dirty bulk if I’m skinny?

You can dirty bulk if you’re skinny, but clean bulking usually yields better results from a body composition and health standpoint. That said, if you struggle to gain weight, eating “hedonistically” may have advantages if you do it sensibly.

For a complete guide to dieting and training to gain muscle as a “hardgainer,” check out this article:

The Best Diet and Workouts for “Hardgainers”

FAQ #4: Is “dirty cutting” good for losing fat after a dirty bulk?

“Dirty cutting” describes an approach to losing weight in which you focus only on the number of calories you consume without paying much attention to the quality of the food you eat. That is, it’s a form of cutting where you can eat “unhealthy” foods, as long as you eat fewer calories than you burn. 

Since dirty cutting involves eating in a calorie deficit, you can lose fat on a dirty cutting diet. That said, there are numerous downsides to dirty cutting. 

For instance, foods with little nutritional value are usually less filling than nutritious foods, so you’re more likely to struggle with hunger while dirty cutting than regular cutting. Additionally, you’re more likely to hit your daily calorie limit before meeting your nutrient requirements. Dirty cutting over an extended period can, therefore, negatively impact your overall health by leading to nutrient deficiencies.

For a better approach to cutting, check out this article:

The Complete Guide to Safely and Healthily Losing Weight Fast

FAQ #5: Is dirty bulking better than not bulking?

If your primary goal is to build muscle, dirty bulking will yield better results than not bulking, especially if you’ve been training for more than 6-to-12 months. 

Most people don’t need to decide between dirty bulking and not bulking at all, though. That is, if you can dirty bulk, clean bulking is likely also an option. And when choosing between dirty bulking vs. clean bulking, clean bulking is almost always superior.