3 Mass Gainer Side Effects (And How to Prevent)

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Mass gainer causes growth – but what other side effects might it cause?

Today, we’re looking over the 3 mass gainer side effects, and what you can do to prevent them. 

1. Digestive Discomfort: Bloating, stomach pain, nausea, and diarrhea

Digestive Discomfort - Bloating, stomach pain, nausea, and diarrhea

Mass gainers may cause bloating as they are liquid calories, but very thick, and rich in carbohydrates. This is a recipe for mild bloating as you rapidly fill your stomach, and the transit of these calories is fast.

This also produces stomach pain, nausea, and – sometimes – diarrhea.

This is more stressful than an equivalent calorie content of food. Food requires chewing and will be taken into the stomach one bite at a time. With liquid calories – and so many – it’s easy to run into a dense calorie source that takes your stomach from empty to full very quickly.

Many people find this uncomfortable, and bloating is a common side-effect for most people. Stomach pain and nausea are less common but still possible.

They come from the same excessive speed and volume of intake, which makes them closely related to bloating. 

These side effects are rarely truly medically dangerous – but they’re always uncomfortable. Let’s take a look at what you can do to prevent bloating with mass gainers…

How do you prevent these digestive side effects?

Step one: product choice. You need to use a mass gainer with a reasonable serving size and calorie content. Excessive calorie intake doesn’t only cause digestive problems but also fat gain.

How do you prevent these digestive side effects

Step two: reduce your serving size in pure volume terms. A half-serving may be the way to go, especially if you’re using a super high calorie gainer (like Optimum Nutrition Serious Mass).

Step three: check the consistency. Too much powder with too little water increases digestive stress. Make sure you’re using plenty of water or milk to maintain a smooth consistency.

Finally, step four, simply don’t chug it. Mass gainer can be consumed slower to reduce the risk of digestive side-effects.

2. Excessive Fat Gain

Using too much mass gainer, the wrong product, or a poor diet can cause excessive fat gain.

Excessive Fat Gain

Mass gainers are high in calories and this is why they’re useful. However, this also puts you at risk of excessive fat gain when you’re trying to build muscle and strength.

This isn’t helpful; it’s bad for health and it’s fat you’ll need to burn off later.

This is easy with super high calorie mass gainers or those with poor protein content. Both of these factors will increase the fat gain potential. When a single serving is around 1300 calories, it’s very easy to accidentally overshoot and cause too much calorie surplus.

How Much Weight Gain Is Too Much?

How Much Weight Gain Is Too Much

You shouldn’t use a calorie surplus over 800 calories unless you’re an incredibly large and strong person. Most people need a 400-800 calories surplus per day, but this range depends on your size. Bigger people can gain more muscle, and thus have later surpluses.

In the opposite direction, you can gain weight on a small (<400 calories per day) surplus, it’s just quite slow. Most people can use a 400-500 calorie surplus to gain weight with very little fat gain.

This is why the average – and often best – recommendation is 500 calorie surplus per day. Almost everyone can use this amount, excepting the very large and very small.

How Do You Prevent It?

The easiest way to avoid gaining fat with mass gainers is to use less of them, lower calorie products, and focus more on diet. A 1350-calorie shake is a bad choice – easy to over-eat and low in nutrients – compared to a leaner mass gainer.

How Do You Prevent It

Use a product that has around 500-800 calories, and you’ll have more control over your intake. Even further, you can use a high-protein choice to reduce fat mass gains even with a larger calorie surplus.

Prioritise your diet, your protein, and small mass gainer shakes. This makes over-eating with mass gainer very difficult and ensures you’re getting the best from your weight gainer supplement.

3. Insulin Spikes and Metabolic Damage

Some mass gainers will cause severe insulin spikes and this can contribute to metabolic disorders and unstable energy levels. 

Insulin Spikes and Metabolic Damage

The problem is that you want to spike insulin after a workout. That’s part of what makes post-workout mass gainer shakes so powerful. However, when there are too many carbs at once, they’re super fast-release, or you’re not exercising, it can add up to health problems.

The main problem is mass gainers that use too many simple carbs – sugars and dextrose – or those with super high calorie counts. (Checkout this list of sugar free weight gainers)

These both promote insulin resistance, which can cause pre-diabetes or other problems (1).

How Do You Prevent Insulin Spikes And Metabolic Damage Using Mass Gainer?

You can prevent insulin spikes and metabolic damage by using a better quality mass gainer. This means:

  • A smaller total calorie content
  • Less sugar per serving
  • A higher ratio of proteins to carbohydrates
  • More protein in total
  • Any fibre content
How Do You Prevent Insulin Spikes And Metabolic Damage Using Mass Gainer

Focus on those mass gainers that balance fast- and slow-absorbing carbohydrates. Look for lower sugar content, and prioritise a higher-protein product. The balance of protein to carbs will determine both the quality of weight gain and the speed of absorption. 

Protein regulates metabolism overall, so keep it at the top of your priority list.

Does Mass Gainer Affect The Kidneys

Does Mass Gainer Affect The Kidneys

No – mass gainer is not linked to kidney damage by any reliable science. It can cause kidney damage in those who already have kidney problems, but is safe at normal serving sizes for healthy people.

This is one of the main misconceptions around mass gainers. It’s a safe, food-based supplement that can be used by most people without any major concerns.

The people who experience negative kidney effects typically have personal pre-conditions that put them at risk of kidney damage

Those with major kidney failure or dysfunction should seek a professional opinion and avoid mass gainers. This is even more true among plant-based mass gainers, which contain more heavy metals (lead, arsenic, and more) than their animal-derived alternative.

Final Thoughts: Do Mass Gainers Cause Side Effects?

Some mass gainers have side effects – and we’ve discussed the 3 main concerns. You want to focus on these common side effects with your choice of product and patterns of use. The better your choice of mass gainer, the lower the risk of adverse effects.

Focus on lean mass gainers, more sustained energy release, and an improved total nutrient profile. These are going to determine the health effects of your mass gainer – and how safe you are.

Final Thoughts - Do Mass Gainers Cause Side Effects

Most mass gainers are completely safe if used responsibly. That is on you – be patient, use smaller doses, and make sure you’re not over-reliant on weight gain supplements for building muscle!

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