I remember being skinny and wanting to gain weight FAST. I didn’t just want to be muscular yesterday, I wanted to be muscular in every single one of my previous lives.
We aren’t just trying to gain weight, though; we’re trying to gain muscle. And if we bulk up too fast, won’t we become skinny fat? That can happen. Not to everyone, but it can happen to some of us. Sometimes. It’s important to understand the risk factors.
Over the past eight years, we’ve helped nearly 10,000 skinny guys bulk up quickly, leanly, and everything in between. Even when dealing with naturally skinny guys, there’s no one-size-fits-all approach.
Let’s discuss the pros and cons of gaining muscle quickly versus gaining it leanly. That way, you’ll know exactly how much weight you should be trying to gain on the scale each week.
- The Tortoise and the Hare
- Why is a Big Calorie Surplus so Effective?
- How to Know if You Should Bulk Fast
- How Quickly Can a Skinny Beginner Build Muscle?
- How Fast Can Intermediates Build Muscle?
- Will Gaining Weight Fast Make Us Fat?
- How to Build Muscle Fast
- How to Make Lean Gains
- How Much Weight Should You Gain Per Week?
- How Much Weight Should You Gain Per Month?
The Tortoise and the Hare
Do Slow & Steady Gains Win the Race?
A new study looked into how different rates of weight gain affected muscle growth and fat gain. Does gaining weight faster yield extra muscle growth? Will gaining weight slower make our gains leaner? This study answers those questions.
Now for the fun part. This study was reviewed in Monthly Applications in Strength Sport (MASS) by Eric Helms, PhD. The title of his review was: When Gaining Muscle, the Tortoise Beats the Hare.
Is that true?
So, first of all, as you probably know, there’s this old Aesop’s Fable about a tortoise and a hare. I’m sure you’ve heard it before. The story goes something like this:
- Once upon a time, a hare mocked a tortoise. “You’re so slow! How do you even get anywhere?”
- The tortoise wasn’t fazed. “I get places faster than you might think. I bet I could even beat you in a race!”
- The hare laughed. What a joke! “Alright, let’s race.”
- When the race began, the hare bounded out of sight, leaving the tortoise plodding in his dust. So far, so good. But the hare soon tired and took a nap.
- The tortoise paced himself. He marched slowly, yes, but he marched steadily. And while the hare napped, the tortoise overtook him, winning the race.
The moral of the story, of course, is that slow and steady wins the race. Persistence outperforms speed.
But what if the hare took a shorter nap? Or what if the tortoise was a little bit slower? Or what if the hare raced to the finish line and then took his nap?
With a story like this, the details make all the difference.
How Slow Are Lean Gains?
Okay, now let’s talk about the new bulking study. The researchers took intermediate natural bodybuilders and split them into two groups.
- The tortoise group ate a modest calorie surplus and gained 1 pound per week on the scale. After 4 weeks, they had gained 2.6 pounds of muscle and 0.7 pounds of fat.
- The hare group ate a massive calorie surplus and gained 2 pounds per week on the scale. After 4 weeks, they had gained 5.3 pounds of muscle and 4 pounds of fat.
Quick note: when Dr. Helms reviewed this study, he noticed that the researchers used a poor way of calculating muscle and fat gains. So I’m using the corrected results from the MASS review, not the study itself.
Anyway, it’s easy to see why Helms favoured the tortoises. By eating in a smaller calorie surplus, they were able to gain muscle three times as leanly:
Does that mean that the tortoises won the race, though? I guess that depends on what the race is. Are you racing to get bigger, to build muscle, or to avoid fat gain?
If you’re just trying to get bigger, gaining weight more quickly is the fastest way to do it. You’ll gain a mix of muscle and fat, making you look much bigger and buffer.
If this is a race to gain lean mass, bulking faster is still better. The hares gained lean mass twice as fast:
This is an impressive amount of lean mass, too. These intermediate natural bodybuilders are gaining over a pound of lean mass every week. They’re gaining fat, too, yes, but that’s a fearsome rate of muscle growth.
The catch is, not all lean mass is muscle growth. Even fat gains contain some lean mass. We can’t say that these bodybuilders were gaining 1.3 pounds of muscle every week. However, most of the lean mass we gain tends to be muscle.
Is Bulking/Cutting Faster than Lean Bulking?
That brings us back to the story of the tortoise and the hare. Remember, the hare didn’t lose the race because he was slower; he lost the race because he had to take a break in the middle.
If we’re talking about bulking, the hares may need a break to cut off the extra fat they gained. We need to factor that break in.
- The tortoise group gained 0.7 pounds of fat.
- The hare group gained 4 pounds of fat.
Keep in mind that the hare group also gained more lean mass. The extra fat will be spread thinner over much larger muscles. And besides, going up a couple of body-fat percentage points might not even matter. It may even help.
For example, if someone is going from 9% up to 14%, the extra fat will make them look bigger in clothes, giving them a fuller face and a thicker neck. That will make most guys look noticeably stronger and healthier:
But for the sake of simplicity, let’s say that the hare group wants to lose that extra 3.3 pounds of fat.
Losing such a small amount of fat can be fast, especially for skinny guys like us. If we cut hard, we could lose it in a single week. That’s extreme, though. Let’s be generous. Let’s say it takes the hares three weeks to lose that extra fat. After all, we’re talking about how much fat we can lose while napping.
During these three weeks, the tortoises are still plodding along. They’re still gaining 0.7 pounds of lean mass per week. Will they catch the hares?
The next thing we need to do is determine our finish line. I dig twenty-pound bulks. That’s usually enough to turn a skinny guy into a fit guy or a fit guy into a strong guy:
So let’s say the goal is to gain twenty pounds of muscle.
Now we can plot out our race:
- The tortoises gain 0.65 pounds of muscle every week, so it takes them 31 weeks to gain 20 pounds of muscle.
- The hares gain 1.33 pounds of muscle every week but need a 3-week break every four weeks. That brings their rate of muscle growth down to 0.76 pounds per week. At that rate, it takes them 26 weeks to gain 20 pounds of muscle.
In this case, the hares beat the tortoises by a whopping five weeks.
Was the Tortoise Even Bulking Slowly?
My favourite thing about this study is the surprise plot twist. Even the tortoises were bulking hard. I mean, if you do some googling about how much weight intermediate lifters should gain per week, here’s what you’ll find:
- Eric Helms from MASS: 0.5–1.5% of body weight gained per month. For a 150-pound guy, that’s 0.2–0.5 pounds per week.
- Andy Morgan from Ripped Body: 1–2% of body weight gained per month. That’s 0.3–0.7 pounds per week.
- Steve Kamb from Nerd Fitness: 2 pounds gained per month. That’s a little under 0.5 pounds per week.
There’s only one exception to the rule:
- Mike Matthews (Legion Athletics): Aim to gain 0.5–1 pound per week.
As you can see, Mike Matthews has the most aggressive recommendation. And even then, the supposed tortoise is bulking at the upper limit of that range.
The tortoise isn’t a tortoise. He’s gaining weight at twice the speed that most people recommend, and he’s making lean gains while he does it.
Looking closer, the tortoise is just a hare in disguise. He shaved his whiskers, painted himself green, tied his ears around his neck, and hid inside a turtle shell. I mean, scroll up and look at that thing. He’s a hare.
Anyway, here’s what happens if we add the typical rate of weight gain to the graph:
The “tortoise” gaining a pound of muscle per week is an argument for bulking fast. It shows that even while gaining a full pound per week, we may be able to make lean gains.
Now, don’t get me wrong, some guys do benefit from bulking more slowly. And other guys may benefit from bulking faster. I think that anywhere from 0.5–2 pounds per week can make sense.
But a pound per week is a good default. And a pound per week is fast.
Why is a Big Calorie Surplus so Effective?
The thing with gaining weight slowly is that your hormones will be fairly average. That’s not bad by any means by any means. But it’s not ideal, either.
By gearing into a larger calorie surplus, you’ll gain a few important advantages:
- Constant nutrient influx allows us to build muscle all day long.
- More testosterone and insulin improve our ability to build muscle.
- More glycogen packed into our muscles improves workout performance and muscle growth.
- Activation of mTOR allows us to construct more muscle.
- More weight gain promotes muscle growth.
In the words of Mike Israetel, Ph.D.:
All else being equal, eating more is the most powerful tool for muscle gain, as long as you’re training hard.–Mike Israetel, PhD
How to Know if You Should Bulk Fast
We’ve seen that bulking very fast is great for gaining tremendous amounts of muscle. We’ve also seen that bulking moderately fast is great for gaining muscle leanly. Both approaches involve rapidly gaining weight, and both approaches can work wonders.
But there’s more than just this one bulking study to consider. Dr. Helms points to this older study, where the hare group was eating 600 calories more per day than the tortoise group, which proved to be too much. They gained slightly more muscle but twice as much fat.
What’s interesting is that the hares were only gaining about a pound per week. That’s not even all that fast, yet most of their gains were fat. So it’s clear that in some circumstances, it’s better to gain weight more slowly.
On the other hand, we also have plenty of research showing rapid rates of muscle gain:
- This study found that beginners were able to gain 9 pounds of muscle during their first eight weeks of working out.
- In this study, another group of beginners was able to gain an average of 12 pounds of muscle during their first ten weeks of working out.
- In another study, beginners were able to gain 15 pounds of muscle during their first 12 weeks of lifting weights.
In all of these studies, the body composition changes were incredible. In one of them, they even lost fat while gaining more than a pound of muscle per week. This means that there are situations where it pays to gain weight more quickly.
Reasons to Gain Weight Slowly
- Strength training: Strength training is great for gaining strength, not building muscle. If you’re doing a strength training program, you’ll want to gain weight more slowly.
- Upper-body emphasis: Over half of your muscle mass is in your lower body. Your quads are your biggest muscles, then your glutes, then calves, then hamstrings. If you aren’t squatting and deadlifting hard, you’ll want to gain more slowly.
- Fatphobia: if the idea of gaining some fat scares you, you may as well play it safe and bulk more slowly.
- Higher body-fat percentage: if you’re pushing 15% body fat, gaining more fat might harm your appearance. If you’re already pushing 20%, gaining more fat could hurt your health, especially if your waist circumference is encroaching on forty inches.
However, even if you’re following a good bulking program, you may still want to bulk more slowly. We’ve had some clients do great with slower bulks. Here’s a sweet progress update from Mikey:
He’s halfway through our bulking program and has been gaining an average of 0.5 pounds per week. I can’t imagine a bulk going better than this. Super lean gains.
Reasons to Gain Weight Quickly
- You’re skinny: the skinnier you are, the more quickly you can build muscle.
- You’re a beginner: if you’re new to lifting weights, your muscles will respond very well.
- You’re naturally lean: if you’re naturally lean, chances are that you have fewer fat cells. You’ll be less likely to gain fat, and even if you do, it will melt off afterwards.
- You’re a hardgainer: if you’re a skinny guy who just can’t gain weight, try being more aggressive. Your body will naturally fight off the fat gains anyway. It’s good at that.
- Hypertrophy training: workouts designed specifically for muscle growth will stimulate more muscle growth. (Obviously.)
- High-carb diet: if your diet is high in carbs (as opposed to fat) then you’ll be able to gain muscle more quickly and leanly.
- Great sleep: if you get a good 8 hours of sleep every night, you’ll be able to build muscle faster and leaner.
- High g-flux: if you have an active lifestyle, you’ll resist fat gain. Doing cardio and spending more time on your feet will allow you to bulk the most aggressively of all.
I’ve always bulked fast. During every one of my bulks, I’ve aimed to gain at least a pound per week. Then, to mitigate fat gain, I tried to optimize my training, diet, and lifestyle.
As a beginner, my gains were lean. As an intermediate, some fat came along for the ride. In either case, I would bulk fast and then rest hard. That’s how I gained 55 pounds in two years:
Over those two years, I bulked hard for 11 months and took things easy for 13 months. That means that while I was bulking, I gained 1.25 pounds per week on average.
We’ve used this approach with about half of our clients, too. Here’s Hugo’s one-year bulking transformation:
I’ll admit a bias. As much as I hate identity politics, let’s be real, hares have a thinner body type. They’re ectomorphs. As Seth Godin would say, they’re part of our tribe. Tortoises are shorter and rounder, and I’m sure they’re very nice, but they’re endomorphs. They’re that pesky body type who keeps out-benching us. I don’t like it.
But despite my bias, I think the facts bear me out. In fact, in situations like ours, even Dr Helms agrees:
Thus, large surplus gaining diets (among natural lifters) should probably be relegated to novice stages and only among relatively lean lifters who can afford to gain some body fat in the process.–Eric Helms, PhD
After helping nearly 10,000 skinny people bulk up, we’ve come to the same conclusion. Aggressive bulking works best for skinny beginners.
How Quickly Can a Skinny Beginner Build Muscle?
When someone starts bulking, they go through a period of rapid muscle growth. This phenomenon is called newbie gains. As the weeks go by, these newbie gains fade. With every inch we add to our biceps, it becomes harder to add another. This is the law of diminishing returns. If you plotted out a beginner’s muscle growth, it would look like this:
However, we aren’t just beginners, we’re skinny beginners. We’re even further away from our genetic potential than the average man. As a result, the effect compounds:
Here’s our article about how big and strong you can get as a skinny guy. Your potential is probably greater than you think. But the point is, if you’re still skinny, chances are that you can build muscle incredibly quickly.
Aggressive Bulking for Beginners
Many skinny beginners can gain upwards of two pounds per week without visible fat gain. Not everyone can do it, and results here vary wildly, but we see it quite often.
If you look at our client transformations, you’ll see that plenty of guys can gain more than a pound per week without any noticeable fat gain, especially during their first 5–10 weeks of bulking.
In fact, Jared himself gained over twenty pounds during his first month of bulking without any visible fat gain. I had never seen anything like it. Since then, we’ve seen a handful of other guys do the same. Given how rare that is, we don’t recommend it. But it happens sometimes.
Here’s another cool example of lean gains while bulking fast:
You shouldn’t expect those exact same results. Everyone is different. This is just to say that as skinny beginners bulking for the first time, we’re in a great position to gain muscle fast.
In our experience, guys starting off lean and underweight (with a BMI under 18) sometimes benefit from gaining 1–2 pounds per week. Then, when they’re no longer underweight, we recommend slowing it down to 0.5–1 pound per week.
Lean Bulking for Beginners
Most naturally skinny guys can build muscle quickly and leanly. Gaining weight more slowly isn’t leaner bulking; it’s just slower.
However, not all skinny guys are naturally lean. We aren’t all starting our bulks at 12% body fat. That can change things. If you’re starting at 15% and you bulk up to 20%, you’re going to start looking out of shape. You won’t be able to see the muscle that you’re building:
That can be hard on some skinny guys. They’re fed up with being small and weak, so they dive into an aggressive bulk. But because they have a higher body-fat percentage, it only makes them even more skinny-fat.
If you’re already up over 15% and feeling a bit soft, it’s often better to shoot for slow and steady lean gains. You won’t build muscle as fast, but you’ll be able to bulk for longer, and you may even lose some fat while doing it. That way, your transformation looks more like this:
If you’re already pushing 20% body fat, we’ve got a different protocol for you. Here’s our article for skinny-fat guys.
Even for naturally lean guys, though, aggressive bulking will eventually lead to fat gains. Once you move beyond that beginner stage, your ratio of muscle-to-fat gains will drop.
And besides, beginners mess up sometimes. So far, we’ve been talking about how beginners can bulk up incredibly fast. And they can. But to get exceptional results, you need to be bulking correctly. Most beginners don’t bulk correctly.
- Beginners don’t always have the wisdom to choose the best hypertrophy programs. It’s common for beginners to take a DIY approach to building muscle. They read a few blog posts and combine bulking methods. That can work if you know what you’re doing… but beginners don’t know what they’re doing.
- Sometimes beginners don’t use hypertrophy programs at all. For example, they may try to bulk with a strength training program, such as StrongLifts 5×5. I don’t have anything against StrongLifts, but at its heart, it’s a strength program, not a muscle-building program. Strength training programs aren’t the same thing as hypertrophy programs.
- Beginners don’t always understand bulking diets. For example, many beginners reduce their carb intake as they gear into their first bulks. That’s not the way. You’ll build muscle more leanly by eating more carbs.
- Beginners don’t always know how to bulk aggressively. Bulking fast isn’t about training six days per week and taking every set to failure. That won’t speed up muscle growth, it will just harm recovery. Nor is it about eating a dirty (or clean) bulking diet.
In fact, it’s so common for beginners to mess up that there’s a term for it: dreamer bulking. It describes a naive bulker who thinks he’s building tons of muscle but is mostly gaining fat.
I don’t mean that in a mean way. Most skinny guys have at least one dreamer bulk before they smarten up. I’ve done it twice, so I’m certainly not above it. I don’t even regret it.
Most former skinny guys consider these dreamer bulks a rite of passage. We gain a bunch of muscle, a ton of strength, and, yes, a ton of fat—but we learn from it. Losing our abs for a couple of months isn’t anything to fear. It may even be worthwhile in the long run.
There are other ways to learn those lessons, though. One approach would be to learn those lessons from others. But if you favour a more DIY approach, that’s cool. I’ve been there. That’s a reason to bulk a bit slower. That way your mistakes won’t manifest themselves quite as flabbily.
If you’re still learning how to drive, no need to practice at 100 mph.
How Fast Can Intermediates Build Muscle?
If you’re a skinny beginner, most experts—myself included—recommend aggressive bulking. Our bodies are so primed for muscle growth that we can push our limits without much downside.
This period of rapid growth might last a few months. Maybe even a couple of years. Then you’ll hit a wall. Upping the calories will just raise your body-fat percentage higher. At that point, aggressive bulking becomes more controversial.
Once you’re an intermediate lifter, experts like Dr. Helms recommend slowing down. They recommend aiming for leaner gains over a longer period of time. This is when he recommends becoming the turtle.
How Fast Should Intermediates Gain Weight?
Let’s plot out an intermediate aggressive bulking example. Let’s say you’re starting your bulk at 180 pounds and 12% body fat, and you’re trying to gain twenty pounds. Let’s say that you’re gaining a pound per week. And because you’re already close to your genetic potential, you’re gaining 50% muscle and 50% fat.
Start of bulk:
- 180 pounds
- 158.4 pounds of lean mass
- 21.6 pounds of fat
- 12% body fat
End of aggressive bulk:
- 200 pounds
- 168.4 pounds of lean mass
- 31.6 pounds of fat
- 15.8% body fat
- +10 pounds of muscle
- +10 pounds of fat
- +3.8% body fat
Now let’s plot out an intermediate lean bulking example. You’re still starting at 180 pounds and 12% body fat, but you’re gaining 0.25 pounds per week. Since you’re gaining slower, your gains should be much leaner. Let’s say you gain 80% muscle and 20% fat.
End of lean bulk:
- 185 pounds
- 162.4 pounds of lean mass
- 22.6 pounds of fat
- 12.2% body fat
- +4 pounds of muscle
- +1 pound of fat
- +0.2% body fat
If we imagine how these results might look, we might get something like this:
Which Results Would You Prefer?
Both approaches would keep you healthy. In either case, you’re well under 20% body fat. And in either case, the quality of your training, diet, and lifestyle might be identical. No issue there.
But the lean gains guy would have better muscle definition and would be able to keep bulking. The aggressive bulker would be much bigger and stronger, but he may need a break.
They’ll have different challenges while bulking, too:
- The lean bulk requires a great deal of precision. It might mean calorie counting, at least for a while. They’ll need that precise 100-calorie surplus every single day.
- The aggressive bulk requires eating more calories. You wouldn’t need to be as exact. 300 or 700 extra calories. Both will result in tons of muscle growth. But eating those 300–700 extra calories every day is no joke. You may wind up feeling perma-full.
If you’re happy with your appearance and want to make gradual improvements, maybe lean gains are for you. Maybe you’d rather be a tortoise. Keep in mind that you need to be precise and that it may take a long time for your results to show.
If you want to build muscle fast and a little fat doesn’t scare you, you’ll prefer a more aggressive approach. You’re a hare. Just keep in mind that you may need to take breaks to cut when your body-fat percentage drifts too high.
Will Gaining Weight Fast Make Us Fat?
The worry that a lot of skinny guys have is that bulking fast will make them fat. There’s a bit of a misconception here. There’s a difference between getting fatter and getting fat. It all depends on how lean you’re starting.
You aren’t fat if you start bulking at 10% body fat and finish at 15%. You’re still well within the healthiest and most attractive body-fat percentage range. You may even look better at 15% body fat. Your neck and face will look fuller, and you’ll look buffer in clothes.
However, some skinny guys get attached to looking ripped. If you prefer being at 10% body fat year-round, I get that. Having striations in your shoulders looks cool. There’s nothing wrong with taking it slow simply because you want to.
How to Build Muscle Fast
We have the “lean and eager” approach for skinny beginners who want to bulk up fast. For them, we recommend gaining 1–2 pounds per week for the first few weeks, then one pound per week after that. That adds up to around 30 pounds over the course of our 5-month bulking program.
We don’t recommend bulking much past 15–20% body fat. That way, even if guys gain fat, they won’t harm their health or appearance. The only thing they’re risking by bulking more quickly is needing to take a break sooner than anticipated.
Bulking fast is fairly simple and doesn’t require much precision. You probably won’t need to count calories, and if you mess up here and there, it might not harm your results. It’s the approach I’ve always taken.
However, it can be hard to eat enough calories to gain weight quickly. Some skinny guys will prefer to gain weight slower simply because it’s easier on their digestive system.
How to Make Lean Gains
We also have the “soft and cautious” approach for guys who want to make lean gains. We recommend that they gain about 0.5 pounds per week during the program.
This approach requires more precision. We recommend tracking calories and aiming for a high degree of consistency. It’s more finicky. But you won’t feel as full, there’s a lower risk of gaining fat, and every day you’ll wake up looking a little bit better.
So in the end, how quickly should you gain weight while bulking? A skinny beginner who’s lean and eager to build muscle should gain 1–2 pounds per week. Everyone else should gain 0.5–1 pound per week.
How Much Weight Should You Gain Per Week?
If you’re trying to bulk quickly, you should gain 0.5–1 pound per week. If you’re a skinny beginner, you might want to gain as much as 1–2 pounds per week.
If you’re trying to bulk leanly, you should gain 0.25–0.5 pounds per week. If you’re overweight, skinny-fat, or having difficulty keeping your gains lean, you can gain weight even more slowly.
How Much Weight Should You Gain Per Month?
If you’re trying to take a longer-term approach to building muscle, you don’t need to focus on gaining weight every week. Instead, focus on progressively overload your lifts in the gym. If you start struggling to gain strength, you can start weighing yourself every month, seeing if your weight is trending upwards. If it isn’t, consider eating a little bit more food. That extra food will help you gain strength and muscle again.
Most skinny beginners can benefit from gaining weight quite quickly when they first start bulking. The extra nutrients open the floodgates of muscle growth, allowing us to build muscle much faster. Yes, gaining weight increases the risk of gaining fat, but with a good bulking program, that fat gain may not even be noticeable.
We usually recommend that skinny guys gain around 1 pound per week while they’re skinny and then switch to gaining 0.5–1 pound per week once they’re at healthier body weight.
We usually recommend that skinny-fat guys gain weight more slowly, gaining closer to 0.5 pounds per week. That way, they build muscle more leanly.
Alright, that’s it for now. If you want more muscle-building information, we have a free muscle-building newsletter. If you want a full workout and diet program, including a 5-month customizable full-body workout routine, a diet guide, a recipe book, and online coaching, check out our Bony to Beastly Program. Or, if you want a customizable intermediate muscle-building program, check out our Outlift Program.