It’s often said that your body is made in the kitchen, not the gym. What you eat significantly impacts your physique, body composition, and ability to build muscle mass.
Not eating enough is one of the cardinal sins of trying to build muscle. It’s also a common mistake that guys make when starting at the gym. Either out of fear of putting on excess body fat or driven by their initial goals to lose weight, guys will start a lifting routine while also consistently maintaining a calorie deficit.
At the other end of the dietary spectrum is what is known as a bulking diet. Weight loss and weight gain always come back to a pretty simple concept: calories in and out.
Bulking happens when you intentionally maintain a caloric surplus– you eat more calories than you burn– for the specific purpose of gaining weight.
It’s common for lifters, bodybuilders, and strength competitors to go through bulking seasons. But why bulk in the first place?
Let’s break down bulking, why folks try to bulk, how to bulk correctly, and whether or not bulking is right for your fitness goals.
For this piece, I’ve called in nutrition and fitness experts from around the world to share their perspectives, insights, and experiences.
Why Try a Bulking Diet?
As mentioned above, bulking is about putting on mass in a relatively short period of time. But what does that mean?
It ultimately comes down to your body’s ability to build muscle. For your muscles to grow in size and strength, your body is going to require more energy than it would to maintain your current body composition.
Eating a caloric surplus, particularly one high in protein, ensures that your body has enough surplus energy and nutrients to fuel muscle growth and development.
Clean Bulk vs. Dirty Bulk
When researching bulking diets, they are often presented as either a clean or a dirty bulk.
A dirty bulk refers to getting your caloric surplus any way you can, often consuming what would typically be considered “junk food,” or foods that are high in calories and low in nutrient density. If someone is doing a dirty bulk, they’re often going to aim for 1 gram of protein per pound of body weight but not be too concerned about their other macros. As a result, dirty bulkers often go for fried foods, pizza, ice cream, processed foods, fast foods, and similar meals. They put on mass quickly, but much of that mass is gained in body fat.
A clean bulk refers to eating a caloric surplus but doing so with nutrient-dense foods. This often includes high volumes of lean proteins, whole grains, vegetables, and foods rich in Omega-3 fatty acids. With a clean bulk, you still maintain a caloric surplus, but because you’re doing so with more healthful foods, you end up putting on less mass overall but with a higher proportion of lean muscle gains instead of body fat.
Why Do a Dirty Bulk if a Clean Bulk is Leaner?
A common question about dirty bulk is why someone would choose to do a dirty bulk if they can build lean muscle mass with a clean bulk.
Ultimately, it comes down to your personal preferences and what is attainable.
For guys who are naturally skinny and struggle to gain weight, eating adequate volumes of lean foods to stimulate weight gain can be a real challenge. Eating a surplus of calorie-dense food that doesn’t have as much volume can be easier.
Another important aspect to consider is that food is expensive. Fresh vegetables, chicken, fish, and other nutrient-dense foods that can help with clean bulking can get very expensive very quickly, especially when you purchase them in the necessary quantities for a successful bulk. By comparison, you can easily hit 2,000 calories with food like pizza for fairly cheap.
If your ultimate goal is mass and you have no other medical conditions that would be agitated by high amounts of processed foods, then a dirty bulk could be a decent option, but there are certain risks (discussed below) that you should consider first.
That said, most personal trainers today will advise against dirty bulking and instead recommend a clean bulk or body recomposition.
What Fitness Professionals Have to Say About Dirty Bulking
Anton Söderström, a Swedish fitness journalist and trainer, recalls his experience trying out dirty bulking as a teenager. He writes, “As a teenager, I was thin as a stick. I started bodybuilding early on, and a dirty bulk was often recommended. I started stuffing my mouth with pizzas, sugary drinks, donuts, ice cream, and the like. I achieved quick results, both in terms of size and the weights I was lifting. My eyes enjoyed the transformation in the mirror, but my body was suffering.”
While he was able to see some short-term gains in size and change the thinness that a lot of young men are insecure about, he also started to notice that there were negative side effects that he hadn’t anticipated.
“The large amount of sugar was creating internal issues. My stomach became irregular, and I often felt stomach pains in the evenings. My heart rate went through the roof while laying on the sofa, and I seemed more prone to colds and infections,” he said. “Not to mention the concentration issues that occurred due to the large amount of sugar I consumed. Being 900 calories above my daily recommended intake, I also developed a lot of stretch marks on my skin. The skin can’t adapt quickly enough to such an intense weight gain.”
Caroline Grainer, an ISSA-certified trainer at Fitness Trainer and a BS in Kinesiology, also points out that dirty bulking may have downsides that people don’t initially realize.
“While it can be possible for dedicated lifters to build lean muscle on junk food diets, this kind of bulking is a short-term goal, and diets are habit-forming,” she writes. “If you want to bulk now and have the right eating habits and metabolism to stay fit in a few decades, take your time and bulk cleanly.”
Söderström reinforces Grainer’s notion that taking your time is ideal. It’s his perspective that dirty bulking is a symptom of a quick-fix culture in which short-term gains are favored while long-term consequences are ignored.
“Like many young men and women, we take a lot of risks and, potentially, compromise our health to look a certain way. It’s an unhealthy culture we have developed. I have met many young adults who’ve developed both bad habits and sickness due to dirty bulking,” he said, concluding, “This quick-fix culture that we have must come to an end. Long-term dirty bulks are a part of that. Having studied the fitness industry for several years and interviewed several people on the matter, I can only conclude that this type of diet has done more harm than good.”
How to Bulk the Right Way
As mentioned, bulking and weight gain go back to a simple principle of eating more calories than you’re burning.
But how many calories is the right amount of calories? Can you lean bulk?
TJ Mentus, an ACE certified personal trainer and fitness coach, advises those interested in bulking to start by assessing their baseline. He writes:
“The first step when deciding to start a bulk is to figure out what your maintenance level of calories is. The basal metabolic rate is the number of calories your body burns just being alive plus the number of calories you burn from activity throughout the day. Not knowing this information will make it incredibly difficult to pinpoint the right amount of calories to eat that will build muscle while limiting the amount of fat put on in the process. The purpose of a bulk is not just to add weight but to add lean mass or muscle. When the calories consumed are too high, the body will start to store fat as it has more than is necessary to build muscle.
Once you know what your maintenance level of calories is, add 500-1000 to that, which is how much you should eat in a day to bulk. Stay closer to 500 if you want to bulk slower and prevent fat gain as best as possible. The higher the calories, the faster you will put on weight but remember that may not all be good weight that you want to gain.”
Adam Kemp, an ISSA-certified personal trainer and professional basketball player, agrees but explains that finding the right degree of caloric surplus may require some experimentation to account for individual differences. According to Kemp,
“Although it is clear that an energy (calorie) surplus is necessary to promote muscle mass gains, the exact calorie needs for peak muscle mass accumulation are less clear. Many factors are involved in muscle growth, and each individual likely has a “sweet spot” for their energy needs to promote peak muscle growth. However, a relative estimate of 1,500–2,000 kJ/day (~360-480 kcal) of positive energy balance is supported by research to promote muscle hypertrophy conditions (Slater et al., 2019). When it comes to macronutrient needs, although carbohydrate and dietary feeds should not be understated, there is less risk of increasing dietary protein consumption in a positive energy balance in terms of gaining fat mass. In other words, increasing protein intake will result in the least fat mass gain if you consume a positive energy balance to gain muscle mass. Protein intake of around 1.8g/kg of body weight has demonstrated positive effects for promoting muscle growth without harming renal function (Slater et al., 2019).”
To sum it up, after calculating your baseline maintenance level of calories, add 500-1000 to that number and try to eat that much each day. You will need to track your food intake to accurately calculate how much you eat. Eating around 500 calories above your baseline will result in a slower, leaner bulk. There may ultimately be some variation based on your individual needs, so tracking your food and progress can help you calibrate your actions for better results.
Do Weight-Gain Supplements Help with a Bulk?
There are high-calorie mass-building supplements available on the market. These are often protein powders mixed with highly caloric supplements intended to make it easier to reach your daily protein and calorie goals, especially if you have trouble eating enough food each day.
However, these supplements’ effectiveness and health benefits are questionable from a clinical perspective.
DJ Mazzoni, a Registered Dietician the Medical Reviewer at Illuminate Health, advises against such supplements, writing in to say,
“The vast majority of bulking and mass gainer powders are composed primarily of highly processed carbs and questionable filler ingredients like artificial sweeteners and food coloring.
For the vast majority of athletes, and especially novice athletes, taking commercial weight gainer products isn’t necessary. Eating calorie-dense whole foods like coconut flakes, avocado or nuts is a much healthier option that’s likely to be cheaper as well.”
How Long Should a Bulk Last?
How long a bulking diet should last depends on your training goals and progress. That said, trainers often recommend bulking for 3-4 months and then entering a cutting phase. In the cutting phase, you shift to a slight caloric deficit, which results in fat loss. Following a pattern of bulking and cutting contributes to strength and mass gains while staying lean.
Unless you are participating in physique-based competitions, cutting likely doesn’t need to be a very intense or stretched-out process and can often occur by bulking for part of the year and then eating at your maintenance level, or slightly below maintenance level, of caloric intake.
Is Bulking Season Actually a Thing?
You may hear the terms bulking season and cutting season thrown around online. These are not formal periods in the year, so if they don’t fit with your training goals, feel free to ignore them. In simplest terms, bulking season refers to the fall and winter, when you are most likely to be bundled up under layers of clothing, which conceal seasonal weight gain. Cutting season is typically spring and summer, leading into beach or pool season when you are more likely to be seen with your shirt off.
Ultimately, these are pretty shallow labels. It’s important to remember that weight gain and weight fluctuation are perfectly normal throughout the year, and whether or not you have visible muscles shouldn’t be a factor in determining if you take your shirt off outside or not.
Is Bulking Right for You?
Now that you know the basics of bulking, you can decide whether or not bulking is an appropriate goal for you.
It is likely right to try a bulk if your core fitness goals include the following:
- Putting on muscle mass
- Increasing your strength gains more quickly
- Getting past a training plateau
However, bulking is probably not the right path forward for you if your primary fitness goals include losing weight, getting lean, or being more concerned with cardiorespiratory performance than strength.
