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ISSA | How Long Should You Bulk For?

How Long Should You Bulk For?

Reading Time: 4 minutes 30 seconds


DATE: 2024-01-04

Bulking is a way of eating used to build muscle. It involves increasing one’s calorie intake, creating a caloric surplus. These extra calories can then be used by the body to help increase lean muscle mass. But you don’t want to bulk indefinitely as this can lead to weight gain. Here’s what we know about bulking, as well as how long this phase should last.

How Bulking Works

The body builds muscle through a process called muscle protein synthesis. Increasing protein intake is one way to fuel this process. However, research has also found that increasing calorie intake, in general, also appears to provide this effect.

One such study was published in the Journal of Human Kinetics. It involved 11 male bodybuilders. Six of them followed a higher-calorie diet. The remaining five followed a moderate-calorie diet. All diets were created by a nutritionist and included protein, carbs, and fat.

These dietary parameters were followed for six weeks, with participants engaging in strength training in weeks two through five. Upon conclusion of the study, those following the diet that was higher in calories had greater gains in muscle mass. (1)

Many bodybuilders utilize bulking to increase their muscle mass. However, a 2022 study suggests that this practice may be becoming more mainstream. It noted that almost half of the males and more than one in five of the female and transgender or gender non-conforming participants had engaged in bulking within the past year. (2)

Bulking is generally done in phases. First people bulk, then they cut. Cutting involves creating a caloric deficit to lose excess body fat, lowering their body fat percentage. Cutting without bulking can result in weight loss. However, it also generally results in a loss of lean muscle as well. Starting with a bulking phase helps prevent this muscle loss. 

Lean Bulking vs. Dirty Bulking

Not all bulking is the same. Some people engage in lean bulking whereas, for others, their bulking phase is “dirty.”

A lean bulk, also known as a clean bulk, focuses on consuming more nutrient-dense foods. This type of eating is both healthy and balanced. Foods consumed on a lean bulk include lean protein (or protein powder), healthy fat sources, and complex carbs.

A dirty bulk consists of consuming a calorie surplus regardless of food quality. This type of bulk often includes a lot of processed foods. Many of these foods contain excess fat, but not the healthy kind. They can also be high in sugar, salt, and other ingredients that don’t support optimal health.

From a nutritional standpoint, lean bulking is healthier. It supports muscle hypertrophy without the adverse effects associated with an unhealthy diet.

How Long Should You Bulk For?

If there’s one thing to understand about bulking to build muscle, this is not a quick process. Like any other muscle growth strategy, it takes some time to provide the desired results.

This being said, there is no true consensus on how long a bulk should last. Some people increase their calorie intake for one to six months. Others create a calorie surplus every day for a year or longer. It’s about figuring out what works best for each individual.

Try a bulking phase for a month or two and see how it feels. During this time, monitor the results. Is your muscle mass increasing? What about your body fat percentage? This is often a delicate balance. You want to build muscle but not increase your body fat—at least not to the point where it is unhealthy.

The risk of bulking for too long is that, in addition to increasing muscle mass, this can also lead to weight gain. Excess body weight increases disease risk. It can also lead to unhappiness with one’s body composition. This can start a dangerous cycle of creating a calorie surplus for muscle growth followed by eating fewer calories to create a calorie deficit and aid in weight loss. Some research even links bulking-cutting cycles with eating disorders. (3)

The bottom line is that it is important to keep bulking in perspective. Aim to gain no more than one pound of body weight per week. If you’re gaining more, it’s likely due to a fat gain versus muscle growth. And if you feel like you’re entering into an unhealthy cycle of weight loss and weight gain, it’s time to reevaluate your approach. 

Determining Your Calorie Intake for Bulking

To determine the number of calories best for you (or a client) when bulking, you must first know how many calories are needed to maintain your current body weight. This is referred to as your basal metabolic rate or BMR. 

The Harris-Benedict formula for calculating BMR is:

Men: 66.47 + (6.24 x weight in pounds) + (12.7 x height in inches) – (6.75 x age in years)

Women: 65.51 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)

You can also use an online BMR calculator instead. This enables you to learn this number quickly. Once you know your weight maintenance calories, increase them by 300 to 500 calories per day. Aim for this number in the bulk phase.

One review found that the average calories consumed by bodybuilders when bulking was around 3,821 per day for males and 3,249 per day for females. (4)

The Other Side of Building Muscle: Strength Training

It’s important to remember that you can’t just bulk and expect muscle growth. Strength training is the other critical part of this equation. If it isn’t, any weight gain experienced is likely due to an increase in body fat and not from building muscle. This is generally the opposite of the body composition you’re working toward.

So, in addition to modifying your diet, be prepared to put in time at the gym. A personal trainer can devise a workout plan based on your specific goals—whether they involve building muscle, weight loss, or something else. Following this plan can help you develop the body composition you desire.

If the trainer is certified in nutrition, they can provide dietary advice as well. They can help you determine the number of calories you need for bulking, cutting, and weight maintenance. By working on both diet and exercise together, you can hit your goals faster and with greater success.

In the end, building muscle requires figuring out the right combination between diet and weight training. If you’d like to help clients with their diet, or even address your own, ISSA’s Nutritionist Certification course can help. It teaches you how to create sound eating plans that supply the proper nutrients but also make it possible to hit one’s goals.


  1. Ribeiro, A. S., Nunes, J. P., Schoenfeld, B. J., Aguiar, A. F., & Cyrino, E. S. (2019). Effects of different dietary energy intake following resistance training on muscle mass and body fat in bodybuilders: A pilot study. Journal of Human Kinetics, 70(1), 125–134. https://doi.org/10.2478/hukin-2019-0038 

  2. Ganson, K. T., Cunningham, M. L., Pila, E., Rodgers, R. F., Murray, S. B., & Nagata, J. M. (2022). “bulking and cutting” among a national sample of Canadian adolescents and young adults. Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity, 27(8), 3759–3765. https://doi.org/10.1007/s40519-022-01470-y 

  3. Ghaderi, A., & Welch, E. (2022). Appearance and performance-enhancing drugs and supplements, eating disorders symptoms, drive for muscularity, and sexual orientation in a sample of young men. Nutrients, 14(22), 4920. https://doi.org/10.3390/nu14224920 

  4. Spendlove, J., Mitchell, L., Gifford, J., Hackett, D., Slater, G., Cobley, S., & O’Connor, H. (2015). Dietary intake of competitive bodybuilders. Sports Medicine, 45(7), 1041–1063. https://doi.org/10.1007/s40279-015-0329-4 

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