A fast metabolism can be a blessing and a curse. Eating more of the right foods is challenging. Volume and consistency are two of the most important variables, when it comes to gaining weight with a fast metabolism. And here, you thought volume and consistency just applied to your training program. 

Someone who has a hard time gaining weight due to a fast metabolism, is often referred to as a hardgainer. A hardgainer is defined as someone who is trying to build more muscle but finds it extremely challenging to put on any weight or gains, regardless of the effort they may be attributing, due to their metabolic rate. The most common reasons why hardgainers have a difficult time achieving their goals, include not eating enough, lack of recovery time, fast metabolism, and not engaging in the right type of physical activity or bodybuilding program.  

Often times, the issues that effect a true hardgainer may go deeper than just the required elements for building more muscle mass, such as nutrition protocol and training regimen. Those issues may be rooted in genetic predispositions and difficulties affecting muscles and muscle protein synthesis. Genetics of course and metabolism again,  also play a huge role in metabolic rate.

How to Gain Weight with a Fast Metabolism: 7 Proven Steps

How Metabolic Rate Influences Weight Gain

Your metabolic rate—the speed at which your body converts food into usable energy—plays a major role in your ability to gain or lose weight. It's why some people can seemingly eat endless amounts of food and stay lean, while others feel like they gain weight just looking at a milkshake.

If you have a fast metabolism, your body burns through calories more quickly, making it harder to maintain a caloric surplus—the key requirement for gaining weight. On the other hand, individuals with a slower metabolism may require fewer calories to reach the same weight gain results.

To put on mass efficiently, you must consistently eat more calories than your body expends. This is known as being in a caloric surplus. The two most important metrics to determine how much you need to eat are your Basal Metabolic Rate (BMR) and your Total Daily Energy Expenditure (TDEE).

BMR reflects the number of calories your body needs to maintain basic physiological functions at rest, while TDEE includes all the calories you burn throughout the day, including those from activity and digestion. Both can be calculated using our FREE online calculators to help guide your weight gain strategy.

Emerging research confirms that metabolic variability can significantly influence dietary outcomes. According to Rosenbaum & Leibel, Nature Reviews Endocrinology, individual differences in resting energy expenditure and adaptive thermogenesis are among the biggest challenges in managing weight, whether gaining or losing.

"Resting metabolic rate can vary by up to 500 kcal per day between individuals of the same size," – Rosenbaum & Leibel, Nature Reviews Endocrinology

By understanding how your metabolism works, you can tailor your nutrition and training to match your body's demands and maximize weight gain in a sustainable, efficient way.

FREE BMR CALCULATOR

FREE TDEE CALCULATOR

How To Gain Weight With A Fast Metabolism

Step 1: Consume More Calories (Strategically)

If gaining weight with a fast metabolism were as simple as “just eat more,” you wouldn’t be reading this article. The truth is, eating more calories isn’t just about shoveling more food into your mouth—it’s about doing so strategically, consistently, and in a way that supports muscle growth without feeling sick or bloated.

Those with high metabolic rates often burn through calories so quickly that they struggle to remain in a caloric surplus—the cornerstone of healthy and sustainable weight gain. A surplus occurs when you consume more calories than your body burns throughout the day, creating the energy reservoir needed to build new tissue, especially lean muscle mass.

Why Calories Matter for Weight Gain

Calories are the building blocks of energy. Without a surplus, your body simply doesn’t have the raw material to build muscle—even with intense training. According to Phillips, Current Opinion in Clinical Nutrition and Metabolic Care, maintaining a caloric surplus with proper macronutrient distribution is essential for hypertrophy and performance adaptation.

“Muscle growth requires a positive net protein balance, which can only occur in a caloric surplus,” – Stuart M. Phillips, Current Opinion in Clinical Nutrition and Metabolic Care

Simple Ways to Boost Your Daily Caloric Intake

Rather than dramatically overhauling your entire diet, try layering in small, high-calorie additions to each meal and snack:

• Add sauces, oils, and spreads to your meals (e.g. BBQ sauce, mayonnaise, jam, peanut butter, Nutella, olive oil, syrup). These are calorie-dense and easy to mix in.

• Drink your calories: Fruit juice, smoothies, full-fat milk, chocolate milk, coconut water, or even high-calorie shakes can dramatically increase your intake without making you feel overly full.

• Add carbs and fats to every meal and shake. Extra rice, avocado, oats, granola, nuts, and seeds can help push meals into the high-calorie zone.

• Include protein + carbohydrate shakes between meals. Whey protein, maltodextrin, dextrose, and nut butter blends make excellent mini-meals.

Gradual Increases Work Best

Start by adding 250–500 extra calories per day, then reassess every week based on changes in weight and energy levels. This ensures sustainable weight gain without unnecessary fat accumulation or digestive discomfort.

If you struggle to gain weight despite these efforts, consider using tools like a food tracking app to accurately assess your intake. Apps like MyFitnessPal or Chronometer can help you consistently hit your calorie and macro goals.

By taking a structured and consistent approach to increasing calories, you can outpace even the fastest metabolism and start making noticeable progress toward your weight gain goals.

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Step 2: Increase Meal Frequency

Yes, eating more often is directly tied to consuming more calories—but it’s also a powerful strategy for optimizing digestion, managing appetite, and improving nutrient absorption throughout the day.

Trying to gain weight by dramatically increasing portion size at just three meals per day can feel overwhelming, uncomfortable, and even counterproductive. Instead, increasing meal frequency—aiming for five to seven meals or snacks per day—can help you gradually build your intake without feeling overly full.

Why Meal Frequency Matters for Weight Gain

Smaller, more frequent meals are easier to digest and often better tolerated by individuals with fast metabolisms. They also help maintain a steady stream of nutrients, which supports muscle protein synthesis and helps you stay in a consistent caloric surplus throughout the day.

According to Antonio & Ciccone, Journal of the International Society of Sports Nutrition, increasing meal frequency may support improved body composition and weight gain when total caloric intake is sufficiently elevated.

“Spreading nutrient intake across more frequent feedings can facilitate improved body composition when energy intake and macronutrient needs are met.” – Antonio & Ciccone, JISSN

How to Add More Meals Without Feeling Stuffed

• Start your day with breakfast within an hour of waking up—skipping breakfast can lead to missed calorie targets later in the day.

• Add mini-meals or snacks between your main meals. Focus on calorie-dense foods like trail mix, granola bars, smoothies, protein shakes, and nut butters.

• Plan your meals around a regular schedule: aim for eating every 2.5 to 3 hours. Set reminders if necessary.

• Don’t skip meals, even if you’re not hungry. Appetite tends to catch up as your body adjusts to higher energy demands.

Over time, your digestive system and hunger signals will adapt to this higher meal frequency. That makes it easier to increase calorie intake consistently without force-feeding or experiencing discomfort.

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Step 3: Track Your Food Intake

If you’re trying to gain weight with a fast metabolism, guessing your calorie intake isn’t going to cut it. You may feel like you’re eating a lot, but without tracking, you have no way of knowing whether you’re truly hitting the calorie and macronutrient targets needed to grow.

Why Tracking Is Essential for Weight Gain

Tracking your food intake provides clarity, accountability, and structure. It eliminates the guesswork and allows you to see exactly how much protein, carbs, fat, and total calories you're consuming—so you can make precise adjustments week to week.

Research supports this approach. A study published in the Journal of Medical Internet Research found that individuals who consistently logged their food intake were significantly more likely to reach their body composition goals than those who didn’t track at all (Burke et al., JMIR).

“Self-monitoring dietary intake is a key behavioral strategy in successful weight management,” – Burke et al., Journal of Medical Internet Research

How to Start Tracking Your Intake

• Use a food tracking app like MyFitnessPal, Macrostax, or Cronometer. These tools allow you to log food intake, scan barcodes, and automatically calculate your macros.

• Weigh your food using a digital food scale. Eyeballing portions can easily lead to underestimation—especially with calorie-dense foods like oats, oils, nut butters, and rice.

• Track every snack, sip, and ingredient. Even condiments, drinks, and oils add up quickly when you’re chasing a surplus.

Use Carbohydrate Increases as a Progress Tool

Once you have a baseline understanding of your intake, a good strategy is to increase your daily carbohydrate intake by ~40 grams per week. Monitor your weight, strength, and energy levels.

If your weight starts increasing steadily (aim for 0.5–1 lb per week), you’ve likely hit the threshold your body needs to grow. If not, continue gradually increasing carbs while keeping protein consistent and fats moderate.

Pro Tip: If you’re unsure where to start, work with a certified nutrition coach at The Swole Kitchen for a customized meal plan, macro breakdown, and ongoing tracking support.

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Step 4: Be Consistent

One of the most overlooked but critical components of gaining weight with a fast metabolism is consistency. Building muscle and adding mass doesn’t happen overnight—it requires a sustained effort across multiple fronts: nutrition, training, and recovery.

With a high metabolic rate, your body burns through energy quickly. This means that even short lapses—skipping meals, slacking on your training, or missing your macros—can quickly set you back.

Why Consistency Is Key for Weight Gain

Staying consistent with your calorie intake, macronutrients, supplementation, and workouts allows your body to adapt, build tissue, and maintain a positive energy balance. Missing just a few days of eating at a surplus or slacking off at the gym may not seem like a big deal, but for hard gainers, it can stall progress or even lead to regression.

As noted by Schoenfeld & Aragon, Journal of the International Society of Sports Nutrition, muscle hypertrophy requires a chronic stimulus—both from resistance training and nutritional support—over time.

“Muscle growth is a cumulative process that depends on a consistent, progressive training stimulus and adequate nutrient intake.” – Brad Schoenfeld & Alan Aragon, JISSN

How to Stay Consistent

• Plan your meals and workouts ahead of time. Meal prep and a structured training split can help you stay on track.

• Set daily calorie and macro goals, and use tracking tools to ensure you’re meeting them.

• Supplement smartly to fill in any nutritional gaps (e.g., protein powder, creatine, greens, or digestive enzymes).

• Don’t skip rest or recovery, as muscle is built during rest—not just in the gym.

Remember, muscle building is a long game. What matters most is not being perfect every day, but showing up and executing your plan with discipline and patience over weeks and months.

Step 5: Supplementation

When paired with a solid training program and high-calorie nutrition plan, supplementation can help accelerate muscle growth, boost strength, and support recovery—especially for individuals with a fast metabolism who need to optimize every calorie and workout.

How Supplements Can Support Weight Gain

Research consistently shows that individuals participating in resistance training or high-intensity functional training, when combined with clinically-backed supplements, experience significantly greater improvements in lean muscle mass, strength, and performance than those who don’t supplement.

In fact, a study published in the Journal of the International Society of Sports Nutrition confirms that strategic supplementation, particularly with creatine and protein, contributes to increases in muscle hypertrophy, body weight, and training capacity (Kerksick et al., JISSN).

“Appropriately timed supplementation in conjunction with resistance training can positively affect strength and body composition.” – Kerksick et al., JISSN

Top Supplements for Gaining Size and Strength

To help you build muscle and gain healthy weight more efficiently, prioritize the following supplements:

• Kre-Alkalyn Creatine – A pH-buffered form of creatine that enhances strength, power, and endurance without the bloating or water retention associated with monohydrate.

• Citrulline Malate – Supports nitric oxide production, blood flow, and muscular endurance. Ideal dosage: 6–8g pre-workout.

• Beta-Alanine – Delays muscle fatigue during high-intensity workouts. Clinical dose: 3.2g daily.

• Whey Protein Isolate – A fast-digesting protein source ideal for post-workout recovery and bridging protein gaps in your diet.

• Clean Carbs – A clean, complex carbohydrate source that helps replenish glycogen and adds quality calories to support weight gain.

You can explore these options in our Best Supplements to Build More Muscle Mass and Strength article.

Avoid Proprietary Blends—Demand Transparency

Many supplement companies under-dose key ingredients by hiding behind proprietary blends. This labeling practice lists a group of ingredients without disclosing the individual dosages—leaving you uncertain about whether you're getting the amount needed for real results.

For example:

• If a pre-workout contains 1–2g of Beta-Alanine, you're far below the clinically supported dose of 3.2g.

• Citrulline Malate is most effective at 6g+, but many formulas contain far less without disclosure.

Pro Tip: Always choose products that are proprietary blend-free, contain clinically effective doses, and are made with evidence-backed ingredients—like those offered by Swolverine.

Smart supplementation can bridge nutritional gaps and provide the edge you need when traditional food sources fall short. But for best results, read the label, know what you’re taking, and use supplements as a strategic tool—not a replacement for whole food nutrition.

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Step 6: Pick the Right Training Program

If you have a fast metabolism, simply lifting weights isn’t enough—you need a training strategy that’s tailored to maximize hypertrophy, volume, and recovery. Because your body burns through calories quickly, every rep, set, and training session must be intentional and focused on progressive overload to stimulate muscle growth.

Why Training Volume Matters for Hardgainers

While lifting heavy is essential to stimulate muscle fiber recruitment and growth, it’s training volume—the total amount of weight lifted over time—that drives hypertrophy. This is especially important for hardgainers, who require greater stimulus and caloric support to trigger size gains.

Gradually increasing volume through linear progression and periodization is one of the most proven methods to promote long-term strength and size improvements. As outlined by Kraemer & Ratamess, Sports Medicine, resistance training programs using periodization techniques are highly effective for optimizing muscular adaptations.

“Systematic variation in volume and intensity over time is key to maximizing muscle hypertrophy and performance.” – Kraemer & Ratamess, Sports Medicine

Best Training Structure for Muscle Growth: High-Intensity Functional Bodybuilding (HIFB)

Bodybuilding-style split routines remain one of the most effective ways to build mass. These splits isolate muscle groups on specific days—like back and biceps, chest and triceps, and legs and shoulders—allowing for maximal muscle fatigue and recovery.

However, for hardgainers, we recommend High-Intensity Functional Bodybuilding (HIFB)—a hybrid training methodology that combines traditional hypertrophy training with functional, athletic movements and higher intensity.

Key Components of HIFB:

• Intensity: 80–90% of your 1RM

• Sets/Reps: 3–5 sets of 10–16 reps per exercise

• Rest Periods: 30 seconds to 1 minute

• Techniques: Supersets, tempo work, functional movements (e.g., sled pushes, carries, kettlebell complexes)

• Split Design: Mimics traditional bodybuilding (push/pull/legs or upper/lower splits)

This approach combines the volume and structure of bodybuilding with performance-driven movement, creating a system that builds both aesthetics and athleticism. It’s especially ideal for fast metabolisms, as the higher intensity and density of training help maximize calorie utilization and muscular fatigue—two critical triggers for hypertrophy.

For a proven HIFB program, check out High-Intensity Functional Bodybuilding Volume II, designed specifically for muscle growth, performance, and metabolic adaptation.

Pro Tip: Don’t just train hard—train smart. Track your weights, monitor your rest intervals, and focus on progression week to week.

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Step 7: If You Need a Gainer, Do It

Sometimes, no matter how hard you try, whole foods and protein shakes alone aren't enough to get the scale moving. If you’re still struggling to gain weight despite hitting the gym and eating more frequently, it might be time to turn to a mass gainer supplement or strategically incorporate high-calorie foods just for the sake of hitting your numbers.

Why Mass Gainers Can Help

Mass gainers are calorie-dense powders specifically formulated to deliver large amounts of protein, carbohydrates, and sometimes fats in a single shake. These can be a game-changer for hardgainers who can’t stomach another solid meal or are struggling to hit their daily intake.

According to Jäger et al., Journal of the International Society of Sports Nutrition, consuming liquid calories—particularly from protein and carbohydrate-rich blends—is an effective way to improve post-exercise recovery, promote muscle growth, and increase total daily caloric intake.

“Liquid nutrition can enhance recovery and support positive energy balance in individuals engaged in resistance training.” – Jäger et al., JISSN

Calorie-Dense Food Hacks for Fast Metabolisms

In addition to mass gainers, don’t be afraid to lean on high-calorie, high-carb, high-fat foods if you’re having trouble eating enough. These may not be your standard “clean eating” staples, but for someone with a fast metabolism, calories are currency.

Here are some practical options to consider:

• Add a doughnut or pastry post-workout to replenish glycogen and boost calories.

• Pop-Tarts, muffins, or bagels can be fast-digesting, carb-heavy snack options.

• Whole milk, trail mix, nut butters, granola, or dark chocolate are all excellent high-calorie add-ons.

• Blend a shake with oats, banana, honey, peanut butter, and protein powder for an easy 600–1,000 calorie meal replacement.

If you’re not gaining at least 0.5–1 lb per week, it’s time to eat more, and sometimes that means ditching the clean-eating perfectionism for pure calorie math.

Need a clean, effective mass gainer? Check out Swolverine Clean Carbs™ for a food-based, gut-friendly source of complex carbs designed to support muscle growth and recovery.

Need Help With Optimizing Your Diet And Nutrition Plan To Finally Get The Results You've Been Waiting For?

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