Both clean bulk and dirty bulk ensure the body is in a calorie surplus by consuming more calories but with attention paid to the quality of food consumed, while the latter disregards the quality of the food.

Both methods of calorie surplus can pack on muscle mass but depending on your goals, one method will benefit you more than the other.

What is Bulking?

When it comes to building muscle, bulking is a diet phase where an individual will consume more calories than they burn. In addition, you provide the body with more than enough nutrients to promote strength and muscle growth.

A bulk prevents any chances of muscle loss occurring from intense weight lifting. This is due to the increased amount of protein and carbohydrates consumed from a bulking diet.

A calorie surplus has been shown to support muscle growth. The study below shows that a calorie surplus can increase FFM (fat-free mass/muscle).

“However, there is an array of circumferential evidence to support the idea that an energy surplus does enhance gains in FFM, even independent of the resistance training stimulus. In an early overfeeding study in which 12 pairs of identical male twins were fed a total energy surplus of 353 MJ (with 15% of total daily energy intake from protein) over a span of 100 days (or 4,200 kJ·day⁻¹), the volunteers gained an average of 5.4 kg FM and 2.7 kg FFM, despite maintaining a relatively sedentary lifestyle.”

Slater GJ, Dieter BP, Marsh DJ, Helms ER, Shaw G, Iraki J. Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training. Front Nutr. 2019 Aug 20;6:131. doi: 10.3389/fnut.2019.00131. PMID: 31482093; PMCID: PMC6710320.

What is a Clean Bulk?

A clean bulk is a form of bulking where a calorie surplus is strictly controlled to minimize fat gains. This includes consuming nutrient-dense whole foods rather than processed foods, maintaining a balanced and healthy diet, and providing only the necessary nutrients to fuel the body for muscle growth.

Clean Bulking Basics

Here are some protocols for clean bulking:

1. Slight Calorie Surplus – The excess amount of calories you consume is slightly higher than your maintenance calories. This can range from 200-350 extra calories.
2. Optimal Protein Intake – You consume at least 1 gram of protein per pound of body weight.
3. Balanced Macros – Your diet has a balanced ratio of carbohydrates, fats, and protein.
4. Progress Tracking – You monitor your weight and food intake throughout the bulk.
5. Consuming Nutrient-Dense Foods – You include lean proteins, complex carbohydrates, healthy fats, fruits, vegetables, and whole grains in your diet.

A clean bulk works best for those who like the “slow and steady” pace. If you want to put on strength fast, a clean bulk isn’t the best choice.

What is A Dirty Bulk?

Dirty bulking is a method of gaining weight by consuming pretty much anything with calories. There is no regard for the quality and nutrition of the food consumed, allowing the individual to reach their calorie surplus easier.

In a dirty bulk, you can consume processed foods, junk food, and high-fat foods. The extra calories will give you the extra energy and nutrients to fuel muscle growth. However, you will accumulate body fat at a quicker pace.

Dirty bulking results in faster weight gain, but a majority of it consists of body fat. Furthermore, this unhealthy weight gain can have negative effects on your overall health. Also, It can make it harder to transition to a leaner physique, as you may require a longer phase of cutting or losing weight to reduce the excess body fat

Dirty Bulking Basics

Here are some protocols for dirty bulking:

1. Higher Calorie Surplus – The calorie surplus in a dirty bulk may be higher than the calorie surplus in a clean bulk.
2. Optimal Protein Intake – You consume at least 1 gram of protein per pound of body weight, which may even be higher in a dirty bulk.
3. Unbalanced Macros – You may overshoot a macronutrient since you a=re eating anything to hit your other macronutrient targets.
4. Less Strict Progress Tracking – You may monitor your calories and macronutrients but they most likely will fluctuate on different days depending on what you consume. Your protein per day may be higher one day, your carbs higher on another day, and vice versa.
5. Consuming All Types of Foods – You consume anything, even unhealthy food choices in order to hit your calorie goal.

So Which Is Better for Building Muscle? Clean Bulk or Dirty Bulk?

If your primary goal is to build muscle, a clean bulk is a better method than a dirty bulk. You accumulate less fat, making your cutting phase shorter.

You definitely don’t want to be in a calorie deficit for too long. Prolonged calorie deficits can lead to muscle and strength loss. In addition, you can only gain muscle at a certain rate, and adding more calories will not speed up this process.

If your primary goal is to get stronger fast, a dirty bulk is the way to go. The extra body weight you can quickly gain from a dirty bulk is leverage for strength. Exercises like the barbell bench, barbell squats, and deadlifts will become easier and you will notice faster progression with the weights you are working with.