bulking vs cutting side by side comparison

Bulking vs. Cutting: Everything You Need to Know About This Muscle-Building Strategy

Got body composition goals? This bodybuilder method might be the solution.

Take one step into the free weights zone at the gym, and you’re sure to hear a gym bro bragging about how shredded he looks while cutting (or at least sneaking a peak and popping a casual flex between sets). For every chum showing off his newly unearthed muscles, you’ll hear an off-season bodybuilder chime in about his bulk in all its glory. Sure, freshly cut muscles are great, but it can’t beat eating whatever you want in bulking season.

To the untrained ear, gym speak like bulking and cutting can sound equally primitive and technical. In reality, they’re simple ways to alter your training and eating habits to either put on muscle (bulk) or shred fat (cut).

Why not simply call it what it is: building muscle and losing fat? That’s the trick. A bulk without a cut is just gaining muscle, and a cut without a bulk is just losing weight. Put them together, however, and you have a unique cyclical formula designed to help you pack on muscle and stay lean.

Bodybuilders and athletes (like wrestlers) have used bulking and cutting for decades to improve their body composition and boost competitive advantage—living proof that it works. The best part: you don’t have to be a bodybuilder to bulk or cut; these tactics can be applied to any fitness endeavor.

Is it right for you? And if so, what’s the most thoughtful (and healthy) approach? We tapped certified personal trainer and nutrition coach James King III, CSCS, PN-1 (an experienced bodybuilder) to find out.

What Is Bulking?

Bulking is known as the muscle-building phase. To do it right, pair a strategic caloric surplus (eating slightly more calories than you burn) with high-intensity resistance training for a set period of time. By doing so, you’ll put in enough work to increase muscle strength and size, while fueling your muscles with the calories they need to rebuild and grow bigger and stronger.

Bulks can be “dirty” or “clean,” but King recommends the latter. A clean bulk is a slower, but healthier approach to building muscle. It involves a moderate increase in calories from healthy, nutrient-dense foods that fuel your muscles with essential carbohydrates, protein, and fats as well as a slew of vitamins and minerals. “A good rule of thumb is to get 80 percent of your calories or meals from healthy sources,” he says. If you eat 21 meals per week, that’s around 17 healthy meals.

If you’re looking for an excuse to eat more junk food, a dirty bulk is the answer. It’s a “strategy” many use to gain muscle, that involves eating whatever you want and hoping for the best. On one hand, it provides ample nutrients for gaining muscle—but, go too far, and you’ll gain excess fat. Plus, eating a junk food-laden diet can increase your risk of obesity, insulin resistance, type 2 diabetes, and cardiovascular disease (1).

What Is Cutting?

Cutting is the phase where you eat in a slight calorie deficit (fewer calories than you burn) to shed body fat while continuing to resistance train to maintain muscle mass. Because you’re short on calories, King points out that it’s even more important to focus on meeting nutrient needs by eating lots of protein, and a variety of colorful fruits, veggies, and whole-grain carbs to fuel your workouts.

During this time, nutrition should be the hard part, but your workouts might feel harder, too. Because you’re cutting calories, you’ll have less energy to put into your lifting sessions. “If you’ve been cutting for a significant amount of time, expect your workout performance to suffer,” says King, “aim to remain consistent with your activity but don’t expect to be putting up any personal bests.”

How to Approach Bulking and Cutting

While losing fat and gaining muscle may seem straightforward, King warns there’s a right (and wrong) way to do it. He recommends focusing more on your body fat percentage than a number on the scale.

Why? If you cut calories you’ll likely lose weight quickly; but, if you’re only focused on the pounds you can lose muscle in the process, too. Muscle loss can increase your risk of injury, weakness, fatigue, and stunt performance. Plus, when you do gain weight, it’s more likely to pack on fat than muscle (2). This phenomenon is known as weight cycling and can lead to dangerous fluctuations in blood pressure, heart rate, sympathetic activity, and circulating levels of glucose, insulin, and lipids (3).

To avoid excessive weight cycling, take a controlled approach, tracking every step of the way and adjusting as needed. King suggests keeping track of progress via body circumference measurements every two weeks, and taking progress photos monthly. “No one likes their before picture, but once you begin this journey, you’ll wish you’d taken those pics,” he says. “Your weight may be similar, but you may notice your waist is smaller or your arms packing on muscle—changes the scale can miss.”

How to Start a Bulk

Most people bulk anywhere from one to six months or longer. To start, King recommends determining your goal weight. From there, aim to gain no more than one to two pounds per week. “The bulk should last the time it takes you to reach your target number,” he says. “For example, if you want to gain 20 pounds, set a goal of bulking for 10 to 20 weeks. Here’s your straightforward guide to bulking (the healthy way).

  1. Determine your maintenance calories. Your maintenance calories are the number of calories you burn daily at rest and during exercise. They’re also the number of calories you need to eat to maintain weight. They will vary by body size, genetics, and activity level. Use an online calorie calculator for an estimate, or talk to a registered dietitian to get it even more dialed in.
  2. Add a 10 to 20 percent calorie surplus. To fuel for muscle growth, you’ll want to add extra calories to your daily diet, but a surplus of 10 to 20 percent might add up to less than you think. For example, a 175-pound person would need to eat about 250 to 500 calories more per day. On the lighter end that’s no more than an extra snack (4). “Start your calorie target on the lower end,” says King. “From there, track for one week. If you experience progress, keep the calorie target the same. If you didn’t progress, slightly increase the calorie goal.”
  3. Get your protein in check. Protein is the building block of muscle. Eat anywhere from 1.4 to 2.2 grams of protein per kilogram of body weight (.7 to 1 gram per pound) per day to fuel for muscle gain (4, 5).
  4. Do high-intensity resistance training. To max out muscle gains, lift heavy and lift often. A combination of heavy strength work and high-intensity hypertrophy work can help you get stronger and sculpt muscle at the same time. As for the best routine, a PPL split or bro split are extremely popular for building muscle.
  5. Track your progress. Weighing in is a common way to track progress, and can ensure you’re not gaining weight too quickly. Just keep in mind, the scale isn’t always the best picture of muscle gain. “Tracking body fat with the help of a coach or learning how to do so using body fat calipers can be better indicators of progress than weighing in,” says King, “I’m also a huge fan of tracking circumference measurements and taking progress photos.”
  6. Reassess and adjust as needed. It’s normal for progress to plateau over time. As it peters off try upping your calorie intake by 150 to 200 calories a day to keep seeing results.

Common Bulking Mistakes

King doesn’t recommend packing on tons of extra calories quickly—that can lead to fat gain and may make you feel sluggish in the gym. Plus, if the excess calories come from unhealthy foods like saturated fat and sugar, you may experience an increase in cholesterol or blood sugar levels, which can increase your risk of chronic disease. Moral of the story: When bulking, make sure to meet your macros and get the right amount of fat, carbohydrates, and protein.

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How to Start a Cut

Most often, a cutting phase is shorter than a bulking phase, lasting anywhere from four weeks to four months. “The success of a cut is most dependent on your ability to stay consistent with your nutrition plan,” says King. Here’s how to cut fat while maintaining as much muscle as possible.

  1. Determine your maintenance calories. Just as with bulking, you’ll want to start by determining the baseline calories you need to eat to maintain weight. Again, use an online calculator or connect with a registered dietitian for a more personalized picture of calorie burn. If you’ve just finished a bulking phase your maintenance calories might be different than when you first started. Adjust as needed.
  2. Subtract 10 to 20 percent of calories per day. For general weight loss, losing one to two pounds per week is considered safe. To maximize muscle maintenance, one study found gradual weight loss of 0.5 to one percent of your body weight per week may be best (7). It may take time, experimentation, and maybe even the help of a professional to find the best strategy for you.
  3. Hike up your protein intake. Keeping high protein levels is essential. It will fill you up and give you energy while helping to spare your body from breaking down muscle for energy while you’re in a caloric deficit. According to one review, it may be helpful to consume significantly more protein during a cut than a bulk. It found that lean bodybuilders respond best to consuming 2.3 to 3.1 grams of protein per kilogram of lean body mass per day. The more lean the bodybuilders were, the more protein they needed to consume to maintain muscle (7).
  4. Keep resistance training. Depending on your sport, you may have heard a cut is all about cardio to help shed the fat. Cardio helps, but maintaining your resistance training routine during a cut will help you maintain muscle while losing fat, too.
  5. Experiment. If you aren’t seeing results, King suggests first making sure you’re consistent with your nutrition plan. “To be more consistent, you must figure out your obstacles and create solutions to improve adherence,” he says. For example, if you can’t help crushing an entire row of Oreos every night, don’t keep them in the house. If you’re consistent with your nutrition plan and still not seeing results, “Aim to decrease your calories by 150 to 200 per day, then track your progress and tweak as needed from there.”

Common Cutting Mistakes

Unlike bulking, the most common misstep with cutting is eating too few calories. If you do, King warns it can lead to a decrease in muscle mass. Maintaining energy is also one of the most challenging aspects of a cut. “Since your calorie intake is lower, it’s important to emphasize quality,” says King. “Quality food, sleep, and stress management can make your cut more manageable.”

What to Eat When Bulking vs. Cutting

The main difference between bulking and cutting is how much you eat, not what you eat. Sure, you’ll have a little more space for extra during a bulk, but it’s still important to emphasize highly nutritious foods during each stage.

In both phases, your main focus should be maximizing nutrient-dense foods that are high in protein, healthy fats, and complex carbs. Aim to eat a variety of colorful fruits and veggies which provide a range of vitamins, minerals, and fiber your body needs to feel full, function properly, and optimize muscle growth.

Focus on:

  • Protein-rich foods: eggs, beef, chicken, fish, pork, tofu, tempeh, greek yogurt, cheese, protein powder
  • Healthy fats: olive oil, avocado oil, nuts and seeds, nut butter, fatty fish (like salmon)
  • Legumes: chickpeas, black beans, pinto beans, lentils
    Complex carbs: whole grains, sweet potatoes, oats, quinoa, brown rice
  • Fruits and veggies: Apples, pears, oranges, bananas, berries, pineapple, asparagus, broccoli, cauliflower, Brussels sprouts, cabbage, zucchini, green beans, peppers, onions, garlic, tomatoes, carrots, celery
  • Leafy greens: kale, spinach, Swiss chard, arugula
  • Drinks: water, sparkling water, tea, coffee


  • Processed foods: deli meat, deep-fried foods like chips and chicken strips, fast food, most frozen and pre-packaged meals
  • Added sugars: pastries, cookies, cakes, candy, soft drinks, sugary coffee, sweet tea, lemonade

If you’re wondering if your favorite bad-for-you foods are off limits, they shouldn’t be, according to King. “For weight loss purposes, no food needs to be 100 percent off limits,” he says, “The best diet is the one you can stick to. Choose an eating style that includes foods you enjoy in moderation.”

Pros and Cons of Bulking vs. Cutting

Both bulking and cutting offer a legit approach to reaching your fitness goals, but there are some potential downsides to both methods. Consider your unique needs before starting a bulk or cut, and when in doubt, talk to your doctor. Here’s what to know.




Promotes muscle gain 

May lead to excess fat gain 

Can increase strength 

Can decrease agility 

Can boost bone density

May make you sluggish 

Allows for efficient recovery from exercise

May affect blood values 

Promotes healthy libido 

Can decrease insulin sensitivity 




Promotes fat loss 

May lead to slight muscle loss

Can improve muscle appearance

Can decrease athletic performance 

Can improve agility 

Can leave you feeling hungry and low energy 

May promote improvement in blood values 

Can decrease bone density 

Can increase insulin sensitivity 

Can decrease certain sex hormones and libido (8)

Bulking and Cutting FAQs

What to know about bulking and cutting before getting started.

Can you bulk and cut at the same time?

If you have visions of cutting fat and building muscle at the same time—good news: it is technically possible. This process is called body recomposition. The catch? One study found it usually only works if you’re new (or returning) to training, overweight and have a high percentage of body fat, or taking anabolic steroids (9). But according to King, with the right training plan, it’s possible for seasoned athletes to achieve body recomposition, too.

Here’s how to do it: “Aim to get progressively stronger in the weight room,” says King. That means tracking your workouts and setting goals for each and every session. On training days, aim for a modest calorie surplus, with an emphasis on protein. “Your protein intake needs to be high enough—at least .7 to 1 gram per pound or more,” says King. For non-training days, eat enough calories to break even, or even a slight deficit to avoid piling on body fat. “Finally, keep lifestyle factors like sleep and stress management in check, they directly impact your ability to recover.”

Should you bulk or cut first?

In most performance-based circumstances, like bodybuilding or wrestling, it’s better to bulk first and then cut if your goal is to build muscle. By doing so, you’re able to pack on as much muscle as possible and then cut down to reach a certain weight class or physique while retaining as much lean muscle and strength as possible. But, it totally depends on your goals. If you’re already packing some extra fat, you may choose to gain muscle while maintaining your calories or start with a cut to shed fat first.

Is bulking and cutting right for you?

If you’re looking to max out your genetic potential for muscle gain, bulking and cutting is one of the best ways to get there. Bulking will help you pack on muscle and fat, and cutting will help you lose the fat to look lean and shredded. But if you have performance goals, you may be better off taking a slow and steady approach—opting for a clean bulk or even recomposition training which involves gaining muscle without the fat at a slower rate. Using this method, you’ll gradually improve your body composition, and will have the energy to focus on workout performance all the time—which if you aren’t on a competition schedule is a more comfortable place to be.

1. Bahadoran, A. et al (2015). Fast Food Pattern and Cardiometabolic Disorders: A Review of Current Studies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772793/
2. Leaf, A. et al (2017). The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition—A Narrative Review. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786199/
3. Rhee, E. (2017). Weight Cycling and Its Cardiometabolic Impact. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6489475/
4. Iraki, J. et al (2019). Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review. https://pubmed.ncbi.nlm.nih.gov/31247944/ 
5. Jager, R. et al (2017). International Society of Sports Nutrition Position Stand: protein and exercise. https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8
6. Helms, E. et al (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. https://jissn.biomedcentral.com/articles/10.1186/1550-2783-11-20
7. Martin, C. et al (2017). Effect of Calorie Restriction on Mood, Quality of Life, Sleep, and Sexual Function in Healthy Nonobese Adults. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4905696/
8. Barakat, C. et al (2020). Body Recomposition: Can Trained Individuals Build Muscle and Lose Fat at the Same Time? https://journals.lww.com/nsca-scj/Fulltext/2020/10000/Body_Recomposition__Can_Trained_Individuals_Build.3.aspx