Macros for Skinny Guys to Build Muscle

The Real Reason You're Still Skinny (It's Not Your Metabolism)

You've been told the right macros for skinny guys to build muscle are complicated, but they're not. The starting point is simple math: eat your target bodyweight in pounds multiplied by 20 for your daily calories. For a 150-pound guy trying to reach 160, that's 3,200 calories. You're not gaining weight because you're not in a calorie surplus, period. It’s not a “fast metabolism.” You’re just not eating enough to overcome your body's daily energy use.

You probably feel like you eat a ton. You have that one huge meal a day and feel stuffed. But when you actually add it up, the total calories for the day are likely far below what you need. A 1,200-calorie dinner doesn't make up for a 300-calorie breakfast and a missed lunch. To build muscle, your body needs a consistent and significant energy surplus. Without it, even the most intense workouts are useless. The protein you eat is used for basic repairs, not for building new muscle tissue. You're stuck in a maintenance phase, spinning your wheels. The solution isn't just “eating more.” It's eating the right amount, consistently, every single day. For a 150-pound guy, that means a target of 3,000 calories and 150 grams of protein, minimum.

Why "Eating More" Fails 99% of Hardgainers

"Just eat more" is the worst advice you can get. It's like telling someone who's lost to "just drive more." It lacks direction and leads to frustration. The reason it fails is that hardgainers consistently underestimate their calorie needs and overestimate their intake. Your body is incredibly good at maintaining its current weight, a state called homeostasis. When you try to eat more, your body fights back by subconsciously increasing its Non-Exercise Activity Thermogenesis (NEAT). You'll fidget more, stand up more often, and burn extra calories without even thinking about it. This is often mistaken for a "fast metabolism."

This is why a specific calorie target is non-negotiable. A vague goal to “eat more” gets erased by your body’s subconscious adjustments. A concrete goal of 3,000 calories is something you can track and hit. The biggest mistake is focusing only on protein. While 1 gram of protein per pound of bodyweight is essential, it only works if you have enough carbs and fats. Protein is an expensive building material. If you don't provide your body with cheap energy (carbs and fats), it will break down that expensive protein for fuel instead of using it to build muscle. You need a surplus of all three macronutrients. Eating 200 grams of protein in a 2,200-calorie diet is a waste. Eating 150 grams of protein in a 3,000-calorie diet is how you grow.

You have the formula now: Bodyweight x 20 for calories, 1g/lb for protein. But knowing the target and hitting it are two different things. Can you say with 100% certainty that you hit 3,000 calories and 150 grams of protein yesterday? Not 'I think I ate a lot.' The exact number.

Your macro numbers. Hit them every day.

Track your food. Know you're eating enough to actually grow.

The 3-Step Macro Formula That Actually Works

Stop guessing and start calculating. This three-step process will give you the exact numbers you need to aim for every day. We'll use a 150-pound male as our example. His goal is to hit 3,000 calories per day to start gaining weight.

Step 1: Set Your Protein for Muscle Growth

This is your foundation. Your muscles are made of protein, and you need enough raw material to build them bigger. The rule is simple and effective.

Action: Eat 1 gram of protein per pound of your current bodyweight.

• For a 150 lb person: 150g of protein per day.

Protein has 4 calories per gram. So, your protein intake accounts for 150g x 4 = 600 calories of your daily total. This number is your anchor. It doesn't change, whether you're gaining or maintaining.

Step 2: Set Your Fat for Hormone Health

Fats are not the enemy. Healthy fats are critical for hormone production, including testosterone, which is essential for building muscle. Skimping on fats is a classic mistake that stalls progress.

Action: Eat 0.4 grams of fat per pound of your bodyweight.

• For a 150 lb person: 150 lbs x 0.4 = 60g of fat per day.

Fat has 9 calories per gram. So, your fat intake accounts for 60g x 9 = 540 calories of your daily total. This provides the hormonal support system for your muscle-building goals.

Step 3: Fill the Remainder with Carbohydrates

Carbs are your primary energy source. They fuel your workouts and replenish the glycogen your muscles use, making them look full and round. After setting your protein and fat, you fill every remaining calorie with carbs.

Action: Calculate your remaining calories and convert them to grams of carbs.

• Total Calories: 3,000
• Protein Calories: 600
• Fat Calories: 540
• Remaining Calories for Carbs: 3,000 - 600 - 540 = 1,860 calories

Carbohydrates have 4 calories per gram. So, your daily carb target is 1,860 / 4 = 465 grams of carbs.

Your Daily Macros for a 150 lb Guy:

• Protein: 150g
• Fat: 60g
• Carbs: 465g
• Total Calories: ~3,000

The First Adjustment: What to Do When the Scale Stops

Follow these macros diligently for two weeks. If you haven't gained at least 1 pound, your body has adapted. It's time to make an adjustment. Add 250 calories to your daily total. Where do these calories come from? Almost entirely from carbs. This provides more workout fuel without adding excessive fat. That's an extra 62g of carbs per day. Do this for another two weeks and assess again. This is the principle of progressive overload applied to your diet.

What 4 Weeks of Gaining Actually Looks and Feels Like

Knowing the numbers is one thing; living them is another. Here is what you should realistically expect when you finally start eating enough to grow. It’s not always comfortable, but it is effective.

Week 1: The "Feeling Full" Phase

This is the hardest part. You will feel constantly full. Eating will feel like a chore. You might even feel bloated. This is your body resisting the change. Push through it. You may see a quick jump on the scale of 2-4 pounds. This is not fat. This is increased water retention, glycogen storage in your muscles, and more food volume in your digestive system. It's a sign the process is working. Your muscles will start to look fuller.

Weeks 2-4: The Steady Climb

After the initial water weight jump, the goal is a steady gain of 0.5 to 1 pound per week. This is the sweet spot for maximizing muscle gain while minimizing fat gain. Weigh yourself every morning after using the bathroom and take a weekly average. If the average is going up by about a pound, you are on the right track. You should feel noticeably stronger in the gym. The weights you used to struggle with will start to feel easier.

The 1-Month Checkpoint: Visible Changes

After 30 days of consistency, you should be 4-6 pounds heavier than your starting weight. Your t-shirts will feel a little tighter around the chest and arms. You will look visibly bigger to people who know you. You will also have gained a small amount of body fat around your midsection. This is normal and unavoidable. Trying to stay perfectly shredded while gaining mass is like trying to drive with the parking brake on. Accept it as part of the process.

That's the plan. Three numbers to hit every single day: protein, fat, and carbs. And you need to adjust them based on your weekly weigh-in. Most people try to track this in a notebook or in their head. Most people fall off by week 3 because it's too much to manage.

Your macros. Every day. On track.

No more guessing if you ate enough. See your numbers hit daily.

Frequently Asked Questions

Best Foods for Hitting High-Calorie Macros

Focus on calorie-dense foods. For carbs, choose rice, pasta, and oats over vegetables. For protein, pick fattier cuts of meat like chicken thighs or 80/20 ground beef. Use olive oil, avocados, and nut butters to easily add fats and calories to any meal.

Dealing with a Lack of Appetite

Liquid calories are your best friend. A shake with 1-2 scoops of protein, a cup of oats, a banana, two tablespoons of peanut butter, and whole milk can easily exceed 800 calories and is much easier to get down than a solid meal.

The Role of Supplements for Hardgainers

Supplements are not magic, but they help. Creatine monohydrate (5g daily) is proven to increase strength and muscle mass. A whey protein powder is an efficient and cost-effective way to hit your daily protein target. Mass gainer powders can work, but they are often just overpriced sugar and protein.

How Much Fat Gain Is Normal

Some fat gain is inevitable and a sign you're in a successful surplus. A good goal is to gain muscle and fat at a 2:1 ratio. If you gain 10 pounds, having 6-7 pounds be muscle and 3-4 pounds be fat is a huge win.

Adjusting Macros on Rest Days

Keep your calories and macros the same on rest days. Your body does the most growing and repairing when you are resting, not when you are training. Providing the necessary nutrients on off days ensures the recovery process is fully fueled. Consistency trumps complexity.