Do Mass Gainers Make You Fat? How to Use Them Properly

Mass gainers do not make you fat on their own, but they can when they push your daily energy intake far above what your body can use to build muscle. A full serve of some gainers adds more than 2,000 Calories, which is several times the surplus most lifters need. Used in the right amount, often a half serve, a gainer is simply an easy way to drink extra food when you cannot eat enough.

How much energy is in a mass gainer serve?

Gainers vary hugely. Here is what a full label serve of four popular gainers in Australia gives you, and what half a serve looks like.

Figures are from each label (one flavour, values vary slightly between flavours). Cost per serve is worked out from the bag size and serves on the label, so use it as a guide.

Why gainers get blamed for fat gain

Muscle growth needs training, enough protein and usually a modest energy surplus. A review of off-season bodybuilding nutrition suggests eating about 10 to 20% more than you burn and aiming to gain about 0.25 to 0.5% of your body weight a week. For someone who maintains on 2,800 Calories, that is roughly 280 to 560 extra Calories a day.

Now compare that with the table. A full serve of Mass Tech Extreme 2000 adds 2,160 Calories, close to four times the top of that range, and that is before you count your normal meals. If the shake goes on top of a diet that already has you gaining weight, the extra energy has to go somewhere, and fat storage is where most of it ends up.

The exact surplus that builds the most muscle for the least fat is still unknown. A 2019 review led by researchers from the University of the Sunshine Coast and the Australian Institute of Sport found the guidance varies widely and has not been tested properly in lifters. That is why watching your weight trend matters more than any formula.

How to use a mass gainer without gaining too much fat

• Start with a half serve. Most people do not need a full label serve. Half a serve of CBUM Mass Gainer (2 scoops) gives about 535 Calories, which sits inside a typical surplus on its own.
• Count it as food. Add it to what you already eat and adjust your meals if your weight climbs too fast.
• Weigh yourself weekly. Sports Dietitians Australia says gains of about 0.25 to 0.5 kg a week are possible early on when everything is right. If you are gaining much faster than that, cut the serve back.
• Check your protein. The bodybuilding review suggests 1.6 to 2.2 g of protein per kg of body weight a day. A gainer helps, but it should not be your only protein source.
• Train hard and consistently. Without a training stimulus, extra energy is far more likely to be stored as fat than built into muscle.

When is the best time to take a mass gainer?

Timing matters less than your daily total, but a few habits help:

• After training, when you want carbs and protein anyway. SDA suggests snacks with carbohydrate and protein before and after training.
• Between meals, so it adds to your day rather than replacing a meal.
• Not right before a meal, because a big shake can blunt your appetite for real food.

Splitting one full serve into two smaller shakes across the day is also easier on your stomach than drinking it in one go.

When does a gainer make sense?

A gainer is worth it if you train hard, struggle to eat enough, and your weight has stalled. SDA notes that energy-dense drinks such as smoothies and liquid meals suit athletes with small appetites. Gainers also suit busy schedules, high-volume sports and people who feel full quickly.

A gainer is probably not for you if you already gain weight easily, or if you are adding fat faster than you would like. In that case a regular whey protein plus a bit more food is a better fit. A homemade shake of milk, oats, banana, peanut butter and whey can also do the job, and SDA notes homemade shakes are often cheaper. Our bulking diet plan shows how to build meals around this.

Our pick

For a leaner bulk, R1 Clean Gainer is the easiest to control at 560 Calories and 30 g of protein per serve, and Rule 1 says it is Informed Choice certified. For hard gainers who need more, CBUM Mass Gainer is one of our best sellers in the last six months, and a half serve gives a sensible 535 Calories at about $3.50 at the time of writing. Save a full serve of a very high-calorie gainer like Mass Tech Extreme 2000 for people who truly cannot eat enough.

Compare more options in our best mass gainer guide, read our CBUM vs Serious Mass vs Mass Tech Extreme comparison, or browse all weight gainers.

How our price compares

Here is what the same products cost at other Australian supplement stores, so you can check the difference yourself.

Supps247 prices come from our website. Other prices were checked on the websites of Nutrition Warehouse, Australian Sports Nutrition (ASN), Elite Supps and Supplement Mart on 29 October 2026 (same product and size, price for one unit) and can change at any time. Sale means it was on sale that day. Some flavours means that price was for some flavours only. Out of stock means it was listed but not available that day. Not listed means we could not find that exact product on their site. Supps247 members can use our Price Match Guarantee against Nutrition Warehouse, ASN, Elite Supps and Supplement Mart: we beat their full price by 5% or match their sale price (conditions apply).

Shop the products in this guide

CBUM Mass Gainer 12 lb$139.95R1 Clean Gainer 30 serves$174.95ON Serious Mass 6 lb$98.95Mass Tech Extreme 2000 12 lb$159.95

Browse all weight gainers.

FAQs

Will a mass gainer make me fat if I do not work out?

It is much more likely to. Without training, your muscles have little reason to grow, so most of the extra energy from a gainer is stored as fat. A gainer only makes sense alongside regular resistance training and enough protein. If you are not training, focus on regular meals instead of adding a high-calorie shake.

How many scoops of mass gainer should I take?

Start with half the label serve and adjust from there. For example, half a serve of CBUM Mass Gainer is 2 scoops and about 535 Calories. Weigh yourself weekly. If your weight is not moving after two to three weeks, add a little more. If you are gaining much faster than about 0.5 kg a week, cut back.

Is it better to take a mass gainer in the morning or at night?

Your total daily intake matters more than the time. Many people take a gainer after training or between meals, so it adds to their day rather than replacing a meal. Avoid drinking a big shake right before a meal, because it can blunt your appetite for real food. Splitting a full serve into two shakes is also easier on the stomach.

Is a mass gainer better than whey protein for bulking?

It depends on your appetite. A gainer adds a lot of carbs and energy, which helps if you struggle to eat enough. Whey protein adds protein with few kilojoules, which suits people who already eat plenty and want to keep fat gain down. Many lifters use whey plus extra food, and switch to a gainer only if their weight stalls.

Can I make my own mass gainer at home?

Yes. Blend milk, oats, a banana, peanut butter and a scoop of whey protein for an energy-dense shake. Sports Dietitians Australia notes homemade shakes can give a similar mix of carbs and protein for less money. A ready-made gainer is simply more convenient and easier to measure, especially if you train away from home.

Sources: Nutrition recommendations for bodybuilders in the off-season (Iraki et al., 2019); Is an energy surplus required to maximise muscle hypertrophy? (Slater et al., 2019); Sports Dietitians Australia: Increasing muscle mass fact sheet; product labels and brand nutrition panels, checked October 2026.

Order online with Australia-wide delivery, free on orders of $99.99 or more, with Afterpay available at checkout. You can also use click and collect at a store that offers it, or visit a Supps247 store in Melbourne, regional Victoria or Brisbane to compare products in person. Members can use our member price match on full-priced items.

Prices and stock were checked on 29 October 2026 and can change at any time. Always read the label and follow the directions for use. If you have a medical condition, are pregnant or take regular medication, check with your doctor first.