When figuring out our ideal bulking macros—how much protein, carbs, and fat we should—there are a few things we need to consider. First, we can look at the research to see which macros allow us to build muscle the fastest. Second, we can see which macros help us avoid gaining fat while bulking. Third, we can look at which macros make it easier to get into a sustainable calorie surplus.
However, a lot of us care about more than merely building muscle. We also want to improve our general health as we do it. So we can also look at which macros have the best impact on our health as we bulk up.
So, what are the best macros for bulking up as a naturally skinny “ectomorph?”
- What Is an Ectomorph?
- How Does Being an Ectomorph Affect Our Bulking Diets?
- How Much Protein Should We Eat While Bulking?
- Carbs Versus Fat While Bulking
- The Benefits of Carbohydrates for Building Muscle
- Do Ectomorphs Need More Carbs?
- How Many Carbs Should We Eat While Bulking?
- How Much Fat Should We Eat While Bulking?
What Is an Ectomorph?
Before we talk about the best bulking macros for ectomorphs, we should define what an “ectomorph” is. It’s a word borrowed from old psychology research that attempted to establish a link between our body types and our personalities. That research has been widely discredited, but even so, the male body types caught on in the bodybuilding community, and naturally skinny guys are still often called “ectomorphs.” (For whatever reason, the women’s fitness community uses different slang. Thin women are usually called “bananas.”)
- Ectomorph: a slang term for someone with a naturally thin body type: thinner bones, lankier limbs, less muscle, and less fat. It’s often used interchangeably with “hardgainer,” which refers to someone who has trouble eating enough calories to gain weight.
So “ectomorph” isn’t a scientific term, it’s just a convenient way to refer to someone who has thinner bones, less fat, less muscle, and a narrower frame.
How Does Being an Ectomorph Affect Our Bulking Diets?
Ectomorphs don’t have a unique physiology, we just tend to have different circumstances and goals. For instance, many of us tend to be naturally skinny, and so a lot of us are trying to bulk up. That puts us in a different situation from the average person.
If we look at data from the American Heart Association, we see a fairly even mix of people who are normal weight, overweight, and obese. It’s a little bit harder to see that little band of grey at the top of the graph, though. Those are the naturally skinny people. Those are the people who are underweight. We represent just 2.8% of the population.
So it’s not that we have alien physiology or that we need to bulk in a totally unique way, it’s just that we have a few unique considerations:
- Most of us are trying to gain weight, not lose it. This means that instead of choosing foods that make it difficult to overeat, we’re trying to choose foods that make it easy to overeat.
- Most of us have less fat on our bodies, improving our ability to clear glucose from our blood (study), improving our ratio of testosterone and cortisol (study), and making us a bit less likely to store fat (study).
- Most of us have less muscle on our bodies, meaning we’re further away from our genetic potential, and thus are able to build muscle faster (aka we can make “newbie gains“).
- Most of us want to train for muscle growth, which means doing hypertrophy training (aka bodybuilding workouts), which allows us to clear even more glucose from our blood (study).
So although we play by the same rules as everybody else, our starting point is quite different, our goals are often quite different, and so our methods often wind up being quite different as well.
When it comes to our bulking diets, for instance, having greater insulin sensitivity (from being lean, lifting weights, and adding muscle) means that we don’t have problems converting carbs into glucose and then clearing it out of our blood. Some people call this benefit having a higher “carb tolerance,” but that term means different things to different people and it’s not used in the research. Even so, it might mean that we do better on high-carb diets than the average overweight person.
In fact, bodybuilders and athletes also do better on high-carb diets for many of those same reasons: they aren’t overweight, they’re trying to build muscle, and they’re engaging in regular exercise and weight training. This, too, often calls for higher intakes of carbohydrates.
How Much Protein Should We Eat While Bulking?
Before we talk about whether ectomorphs should eat more carbs, let’s quickly cover protein. Our muscles are constructed out of protein, so if we aren’t eating enough protein then we can’t build muscle. As a result, it’s much more important to eat enough protein than it is to eat enough carbohydrates.
How much protein do we need? Most research shows that muscle growth is maximized at 0.8 grams of protein per pound bodyweight per day while bulking, with some research pointing to a slightly higher intake of 1 gram/pound/day (study). There’s no harm in eating a bit too much protein, and so we usually recommend aiming for a full gram/pound/day (study, study, study). That builds in a bit of leeway. If the nutrition labels exaggerate the protein contents of our foods or if we miscalculate our protein intake, we’re still eating enough to build muscle at full speed. For a 150-pound man, that means eating 150 grams of protein per day, which often works out to around 20–30% of our overall calorie intake.
The protein recommendations for building muscle are around twice as high as the recommended protein intake for a sedentary person, and so not eating enough protein is a common problem for some beginner lifters, vegetarians, and vegans. They eat too little protein, and so they struggle to build muscle. If they’re gaining weight without being able to gain muscle, that results in a disproportionate amount of fat gain. That can be a real problem, especially for skinny-fat guys.
However, although it’s true that protein is essential for building muscle, it’s not a case where more is better. Once we’re hitting that minimum requirement for building muscle, eating more protein on top of that has little benefit beyond the extra calories that we get from it. For example, in this study, the researchers fed the participants 550% of the recommended amount of protein and they still didn’t gain any extra muscle whatsoever.
As we mentioned above, it’s not unhealthy to eat extra protein. If you prefer it, that’s perfectly fine. But most people find that high-protein diets make it harder to eat enough calories to gain weight. In the words of Mike Israetel, PhD:
[Protein] has such a profound effect on suppressing hunger that gaining weight by adding tons of extra protein turns into an incredibly uphill battle to get in enough calories. A battle that most people lose.Mike Israetel, PhD
Not only is protein incredibly filling, we produce extra body heat as we digest it, causing our metabolisms to rise. This phenomenon is called the Thermic Effect of Food(TEF) or Diet Induced Thermogenesis (DIT). Here’s an example of that:
- If we eat 1000 calories of fat, our bodies burn off 15 calories as heat.
- If we eat 1000 calories of carbs, our bodies burn off 75 calories as heat.
- If we eat 1000 calories of protein, our bodies burn off 250 calories as heat.
If we’re trying to gain weight, then, it may be easier to get our extra calories from carbs and/or fat, and there may even be some extra advantages to doing so.
So to summarize, it’s crucial that we eat enough protein while bulking (around 0.8–1g/lb/day). Otherwise, we won’t be able to build muscle at full speed. However, eating even more protein than that doesn’t seem to yield any extra muscle growth, but can make it harder to eat enough calories to gain weight.
Carbs Versus Fat While Bulking
The most important parts of a bulking diet are that we eat enough calories to gain weight and enough protein to build muscle. However, once our protein requirements are met, we can get our extra calories by either eating more carbohydrates or more dietary fat. Getting more calories from carbs and fat tends to make it much easier to eat enough calories to gain weight.
The Journal of the International Society of Sports Nutrition recommends getting most of our extra calories from carbs, which often works out to around 40–60% of our overall calories. The National Strength & Conditioning association makes similar recommendations, noting that getting 45–65% of our calories from carbohydrates tends to be best for our general health, best for weight training, and best for gaining muscle. They note that some people might prefer a low-carb approach, which they say is fine, but that it tends to work best for overweight people and that it isn’t ideal for hypertrophy training, general health, or building muscle. This lines up with bodybuilding research looking into muscle growth, too (study, study).
The next question, then, is why? Low-carb and keto diets are popular among overweight people who are trying to lose fat. Why does it work for them but not for skinny guys, bodybuilders, and athletes who are trying to build muscle?
The main difference is that overweight people are trying to burn their body fat for energy. If they lift weights, eat enough protein, and get into a calorie deficit, it’s not that important if they get more calories from carbs or fat because they aren’t storing any energy anyway. But for guys who are trying to bulk up, we’re storing the extra calories we’re eating, and dietary fat is very easily stored as body fat.
For example, in this 2-week study, they compared lean and overweight participants, seeing whether they responded better to carb or fat overfeeding. The overweight participants gained roughly 33% muscle and 67% fat, which is the ratio that’s often used when talking about the muscle-to-fat ratio of people who overeat without exercising.
However, the results of the lean participants were different. Not only did they gain more muscle and less fat, but their intakes of carbs and fats also had an impact on their ratio of muscle-to-fat gain. The first group was overfed with carbohydrates, the second was overfed with fat. Neither group lifted weights or exercised. But eating more fat caused less muscle growth and more fat gain (47% muscle, 53% fat) whereas getting a calorie surplus from carbs caused more muscle growth and less fat gain (56% muscle, 47% fat).
Now, it’s important to note that none of the participants were working out or eating enough protein, and so the ratio of muscle-to-fat gain was horrible in both groups. But even so, this suggests that getting more of our calorie surplus from carbs reduces fat storage while bulking, especially for people who aren’t overweight.
If we combine a good bulking diet with a good bodybuilding program, enough protein, and good sleep, we can build muscle much more leanly than that.
For instance, this study found that adding 1,800 calories of carbohydrates into the diets of men who were following a rigorous bodybuilding program caused rapid muscle growth with simultaneous fat loss.
We see similar results in some members of our Bony to Beastly Bulking Program. Results vary, of course, but by eating enough protein, following a good hypertrophy training routine, getting enough sleep, and eating plenty of carbohydrates, we’re often able to build muscle quite quickly and leanly.
Getting our extra calories from carbs while bulking causes less fat gain (study), more muscle growth, and may have a better impact on our general health (study). This makes higher-carb diets a good default option when bulking, especially for guys who are naturally skinny, such as so-called “ectomorphs” and “hardgainers.”
The Benefits of Carbohydrates for Building Muscle
The next benefit of a higher carbohydrate diet while bulking has to do with glycogen, energy, and muscle growth. When we eat a diet that’s higher in carbohydrates, our muscles store extra glycogen, making them look fuller and harder, and also giving them more energy that we can use during our muscle-building workouts. Having that extra energy improves our workout performance, allowing us to stimulate more muscle growth. In addition to that, having muscles that are packed full of glycogen seems to accelerate our rate of muscle growth.
There are a few reasons why higher-carb diets work so well for bulking in general:
- Eating more carbs lowers our protein oxidation, allowing us to use the protein we’re eating more efficiently.
- Carbs cause more of the weight we gain to be muscle, less to be fat (study)
- Carbs increase testosterone and reduce cortisol when compared to fats (study)
- Higher-carb diets produce more insulin which produces more muscle growth (study)
- Carbs can be stored in our muscles in the form of muscle glycogen, making it less likely for those calories to be stored as body fat (study)
- Carbs improve our workout performance, allowing us to stimulate more muscle growth (study)
- Carbs tend to be affordable (e.g. rice, beans) and easily prepared (e.g. bananas, oats)
- Carbs strengthen our immune system and reduce our chances of getting sick while lifting weights (study)
Do Ectomorphs Need More Carbs?
Ectomorphs don’t need more carbs, but we often tolerate them quite well. In fact, there are a few reasons why carbs can help naturally skinny people bulk up:
- Carbs aren’t as filling as protein, making it easier to eat more calories (study).
- Ectomorphs are leaner and tend to have a higher carbohydrate tolerance (study).
- Lifting weights improves our ability to handle high-carbohydrate diets (study).
- Gaining muscle mass while bulking further improves our carb tolerance (study).
Again, I know this may sound counterintuitive, considering that carbs are infamous for causing weight gain. The difference is that we’re trying to gain weight. Furthermore, since we’re lean and lifting weights, we often have greater insulin sensitivity than the average person, putting us in a unique position to benefit from eating more carbs.
With that said, even if we look at obese people who lift weights while eating a low-carb diet, we see that they tend to lose both fat and muscle, whereas the group eating more carbohydrates tend to build more muscle (study).
Overall, bulking on a diet that’s higher in carbohydrates increases the amount of glycogen in our muscles, improves our workout performance, and increases our rate of muscle growth, allowing us to gain muscle more quickly and leanly.
How Many Carbs Should We Eat While Bulking?
As a general rule of thumb, an ectomorph should get around 50% of their calories from carbs while bulking. Or, if you prefer counting grams, getting a minimum of around 3 grams of carbohydrates per pound bodyweight per day tends to be ideal. That will leave enough room for protein and fat, and the higher proportion of carbs will help you gain muscle more quickly and leanly.
Then, the leaner and more active you are, the higher your metabolism and carb tolerance will be. If you’re bulking on 20x your bodyweight in calories per day or more (e.g. a 150-pound guy bulking on 3000 calories) it might help to get more of those extra calories from carbs, which might drive your carb intake up closer to 60%.
For example, a 150-pound ectomorph might bulk on:
- 20x his bodyweight in calories per day (3000 calories)
- 3 grams of carbs per pound bodyweight (450 grams)
- 60% of his calories from carbs (1600 calories).
However, this isn’t the only way to bulk. It’s certainly possible to bulk on a low-carb diet. The most important factors while bulking are to follow a good hypertrophy training/bodybuilding program, to eat enough protein, and to get enough good sleep. It can help to combine that with a higher intake of carbs, but it’s not required. It’s ultimately up to you.
To summarize, getting at least 3 grams of carbs per pound bodyweight per day tends to be ideal for bulking. That often works out to around 50% of our calories coming from carbs. But that’s just a good default. It’s not required. It’s okay to eat more or fewer carbs.
How Much Fat Should We Eat While Bulking?
Now that we’ve covered protein and carbohydrate recommendations for bulking, to figure out your overall macros, just fill in the rest of your calories with fat:
- 0.8–1 gram of protein per pound bodyweight per day (around 20% of calories)
- 3+ grams of carbs per pound bodyweight per day (around 50–60% of calories)
- The remaining 20–30% of our calories from fat.
When it comes to choosing your sources of fat, there’s no need to intentionally avoid saturated fats, but it’s important not to intentionally drive your saturated fat intake too high. For example, sometimes skinny guys will start drinking tons of whole milk in order to bulk up (GOMAD, LOMAD), which is a great way to increase your calorie intake. However, whole milk is high in saturated fat, which can drive your saturated fat intake way too high, causing loads of extra fat gain.
Better to aim for a mix of different fats. It’s okay to eat eggs, drink whole milk, and eat some meat, yes, but we also want to make sure to eat plenty of polyunsaturated sources such as nuts and olive oil, and also get some EPA and DHA from eating fatty fish (or supplementing with fish oil). We want to aim for a balanced overall intake of fat.
The most important macronutrient for building muscle is protein. Given that muscle is built out of protein, failing to eat enough of it can radically reduce our rate of muscle repair and growth. Getting 0.8–1 grams of protein per pound bodyweight per day is ideal, which usually works out to around 20% of your calories coming from protein.
After protein, we need to make sure that we’re eating enough dietary fat. Not only can fat be rich in nutrients, it’s also needed for maintaining healthy hormone function while building muscle. However, we need to be careful about overfeeding on fats while bulking, given that it can cause us to gain proportionally more body fat. It may also help to keep our intake of saturated fat within reasonable levels. Getting 20–30% of our calories from fat is ideal, with only around a third of that coming from saturated fat (7–10% of total calories).
Once we’re eating enough protein and fat, the more carbs we can eat, the better. Ectomorphs tend to build muscle the most quickly and leanly when 50–60% of their calories come from carbohydrates, which usually works out to around 3 grams of carbohydrates per pound bodyweight per day. We don’t need to be precise with our carb intake, though.
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