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Weight gainers: the ultimate guide

Everyone has different bodies, goals and ideas of what fitness means to them. If you’re looking to put on weight, pack on muscle mass or simply get more calories into your system, weight gainers might support you. Here, we’ll cover everything you need to know about them — what they are, how they work, and the benefits of using them. Find our top tips on choosing the best weight gainer for you, learn how to use them effectively, and have some of your most commonly asked questions answered.  

What are weight gainers? 

Weight gainers, or mass gainers, are high-calorie, high-protein powders or snacks designed for anyone looking to increase muscle mass (protein contributes to the growth and maintenance of muscle) or put on weight for various health or personal reasons. You won’t gain weight just by taking a weight gainer, although they will help you up your calorie intake so you can maintain a calorie surplus, i.e. consume more calories than your body needs. They typically contain a blend of carbohydrates, protein, and sometimes fats, as well as additional vitamins and minerals.  

The primary purpose of mass gainers is to provide a convenient and easy way to consume a high number of calories and protein in a single serving, without having to eat large amounts of food. They’re often used by individuals who have a hard time gaining weight or struggle to get enough calories and protein from their diet alone. 

Note: weight gainers are not the same as meal replacement shakes — you can read all about those in our article: shakes for weight loss.  

What are the best weight gainers at Body&Fit? 

Over our 25 years in the sports nutrition industry, we’ve developed a complete range of high-quality weight gainers. Our top sellers include: 

Mass Perfection  

Our Mass Perfection delivers 20g of whey protein isolate & concentrate, 29g of carbohydrates (from Scottish oats, brown rice and Palatinose — a naturally sourced smart carbohydrate) and 235 kcal per serving. The deliciously creamy taste makes Mass Perfection a must for anyone working hard to get a bigger physique.  

Clean Gains 

You won’t find any added sugars, stevia, or artificial sweeteners in Clean Gains. This makes room for 37g of protein and carbohydrates (from oat flour and others) and 352 kcal in each serving. And there’s more. A vitamin and mineral blend helps support your daily nutrient intake, covering a minimum of 30% of the recommended intake. 

Massive Gainer  

Ideal for any bulking phase, Massive Gainer packs in a whopping 51g of protein and 1087 kcal per serving. It’s been enriched with a complete spectrum of vitamins and minerals (A to Z), contains fats from coconut oil powder and has been developed without added sugars*. The carbohydrate content of this weight gainer comes from maltodextrin, oat flour and rice flour. 

*contains naturally occuring sugars 

How do weight gainers work? 

Weight gainers work by providing your body with a surplus of calories and protein. Of course, you need extra calories to gain weight, while protein is essential for growing and maintaining muscle mass. They’re mostly taken in the form of a shake, which provides a convenient way to consume these extra nutrients.  

What are the benefits of mass gainers? 

There are several benefits of using mass gainers to support your goals. 


One of the most significant benefits of using mass gainers is their convenience. They provide a quick and easy way to consume a large number of calories and protein in a single serving, which can be especially helpful for individuals who have a hard time eating enough food throughout the day. 

Increased calorie & protein intake 

Mass gainers are an excellent way to increase your calorie and protein intake. They provide a concentrated source of nutrients that can help you reach your daily caloric and protein needs. 

Improved muscle growth & recovery 

The protein in mass gainers can help to support muscle growth, while carbohydrate solutions contribute to the improvement of physical performance during a high-intensity (at least at 65% of the VO2max) and long-lasting (at least 60 min) physical exercise in trained adults*. 
* applies only to carbohydrate solutions that provide between 30g and 90g of carbohydrates/hour, where the carbohydrates in question are glucose, sucrose, fructose and/or maltodextrins, under the following conditions: 

a) fructose (from fructose and/or sucrose) should not represent more than 1/3 of total carbohydrates, and 

b) glucose (from glucose, sucrose and/or maltodextrins) should not exceed 60 g/h. 

Additional nutrients 

Many mass gainers also contain additional vitamins and minerals that can help to support overall health and wellbeing. 

What are the potential downsides of weight gainers? 

Depending on your specific goal and circumstance, the potential downsides of weight gainers may include their: 

  • High calorie content — mass gainers are typically very high in calories, which can be a drawback for individuals who are trying to maintain a lean physique or who are not used to consuming a high number of calories. This amount of calories can also mean there’s a lot of shake to consume, which can be a struggle for some.  

  • Cost — weight gainers can be more expensive than other protein supplements, which may be a concern for individuals on a tight budget. 

  • Quality — not all mass gainers are created equal, and some may contain lower quality ingredients or fillers. It’s essential to choose a high-quality mass gainer that contains a blend of carbohydrates, protein, and fats. 

Finding the best weight gainer for you 

When it comes to choosing the best weight gainer for your needs, there are a few key factors to consider: 

Calorie & macronutrient content 

Look for a weight gainer that provides an appropriate amount of calories and macronutrients to support your goals. If you’re looking to gain weight and build muscle mass, you’ll want to choose a mass gainer with a higher calorie and protein content. You’ll also want to consider your normal calorie intake and find the right balance when adding in a gainer. 

Quality ingredients 

Choose a weight gainer that contains high-quality ingredients, such as whey protein, complex carbohydrates and fats. Avoid products that contain excessive amounts of sugar or artificial ingredients. 

Serving size & dosage 

Pay attention to the serving size and dosage instructions on the product label. Make sure that the serving size fits within your overall daily calorie and macronutrient needs and follow the dosage instructions carefully. If you find a serving is too much, you can always consume it in two portions. Just remember not to exceed the suggested dosage. 


Consider the price of the mass gainer and choose a product that fits within your budget. Keep in mind that higher-priced products may contain higher quality ingredients or a more comprehensive nutrient profile. 

How to use weight gainers effectively 

To use mass gainers effectively, it’s important to follow a few simple guidelines: 

Combine with regular exercise 

Mass gainers are most effective when combined with regular exercise, especially resistance training. This will help to ensure that the additional calories and protein are used to build muscle mass. Of course, it is inevitable that you will also gain weight in fat during a bulk phase with such a surplus of calories.   

Use as part of a balanced diet 

While weight gainers can be an excellent way to supplement your diet, they should not be used as a replacement for whole, nutrient-dense foods. Make sure to use mass gainers as part of a balanced diet that includes plenty of fruits, vegetables and proteins. 

Use consistently 

To see the best results, use mass gainers consistently over time. It can take several weeks or even months to see significant changes. 

Weight gainers: your FAQs 

Our team of Nutrition Experts get asked lots of questions about weight gainers. Here, you’ll find answers to some of the most common ones they hear. 

What are the main differences between different types of weight gainers? 

Understanding the main differences between different types of weight gainers can help you choose the one that aligns best with your specific goals and preferences. The key factors that set them apart are: 

  • calorie content 

  • protein-to-carb ratio 

  • source of carbohydrates & proteins 

  • fat content 

  • additional ingredients & nutrients 

  • taste & mixability. 

Is it important to take creatine when using weight gainers? 

When it comes to muscle growth, creatine is a popular supplement that many individuals consider incorporating into their routine as it stimulates muscle growth/(lean) muscle mass during explosive strength exercise.  

Explore our article — everything you need to know about creatine — to get the complete lowdown on this popular and widely studied supplement. 

Should I combine weight gainers with other products? 

If you’re considering using weight gainers as part of your fitness journey, some good supplements to combine with them are creatine, BCAAs, omega-3 fatty acids and multivitamins 

How many calories do I need to gain weight? 

To gain weight, you’ll need to consume a caloric surplus above your Total Daily Energy Expenditure (your TDEE represents the number of calories your body needs to maintain its current weight). This surplus typically ranges from 250 to 500 calories per day. It’s important to aim for a gradual weight gain of 0.2 – 0.4 kg per week to ensure it’s healthy and sustainable. Remember to focus on nutrient-dense foods and consult with a healthcare professional or registered dietitian for personalised guidance based on your individual needs and goals. 

Which Body&Fit weight gainer contains the most calories? 

Delivering 1087 kcal per serving, our Massive Gainer contains the most calories among our range of weight gainers. 

What carbohydrate sources are used in weight gainers? 

The carbohydrate sources used in mass gainers can vary, and understanding the differences between them is important for making an informed choice. The main carbohydrate sources found in weight gainers are: 


A common carbohydrate source in weight gainers derived from starch, Maltodextrin has a high glycemic index, meaning it is rapidly absorbed by the body. It provides a fast and efficient source of energy and helps replenish glycogen stores. 


Another fast-release carbohydrate, Dextrose is a simple sugar derived from corn. Like maltodextrin, it has a high glycemic index and is often used in weight gainers as such carbohydrates contribute to the recovery of normal muscle function (contraction) after highly intensive and/or long-lasting physical exercise leading to muscle fatigue and the depletion of glycogen stores in skeletal muscle. 

* the beneficial effect is obtained with the consumption of carbohydrates, from all sources, at a total intake of 4 g per kg body weight, at doses, within the first 4 hours and no later than 6 hours, following highly intensive and/or long-lasting physical exercise leading to muscle fatigue and the depletion of glycogen stores in skeletal muscle. 


Oats, like our Ultra-Fine Oats, are a complex carbohydrate source that provides a slower release of energy compared to maltodextrin or dextrose. They’re also a good source of fibre and contain additional nutrients such as vitamins and minerals. 

Other weight gainers may contain further complex carbohydrate sources like brown rice, quinoa, or sweet potatoes.  

How long should I use weight gainers for? 

The length of time you should use weight gainers will depend on your individual goals and needs. It’s generally recommended to use them consistently for several weeks or months to see the best results. You may also want to cycle off mass gainers periodically to give your body a break and prevent dependence on supplements. 

Weight gainers in a nutshell  

If you’re looking to gain weight and build muscle mass, weight gainers can be an excellent tool. They provide a convenient and easy way to feed your gains with additional calories and protein. When choosing a mass gainer, make sure to consider factors such as calorie and macronutrient content, the quality of its ingredients, serving size, dosage and price. Use consistently as part of a healthy, balanced diet and alongside plenty of exercise to get the results you’re after. For any further information on our selection of weight gainers, feel free to contact our Nutrition Experts via Instagram or the customer service channel on our site.