How to Find the Best Meal Replacement Shakes for Weight Gain

📌 Overview and Key Takeaways

This is a Dietitian’s guide on how to find the the best meal replacement shakes for weight gain.

Discover how to safely supplement your diet.

Last Updated
Feb 6, 2026

Author and Medical Reviewer

Written by Kayla Kamen, MS, RD

Kayla Kamen is a Registered Dietitian with a MS in Nutrition.

Medically reviewed by Jennifer Fossett, PA-C

Jennifer Fossett is a Physician Assistant with a BA in Nutritional Sciences.

Meal Replacement Shakes for Weight Gain

Can Meal Replacements Help Me Gain Weight?

Although meal replacements are often championed as a weight loss food, the can also help you gain weight.

This is in part because they make it easy to add calories and nutrients to your diet.

Not only are meal replacement shakes calorie-dense, but they are also easy to prepare and drink, which can help you avoid missing meals.

Keep in mind that at the end of the day, gaining weight comes down to eating more calories than you burn.

Also note that it takes an extra 3,500 calories to gain a pound, and to gain weight at a safe rate (0.5 pound per week), you need to eat an extra 250 calories per day.

It is worth adding that if you are looking not only to gain weight, but also to build muscle, then you have to eat lots of protein.

Muscle growth can occur only if muscle protein synthesis exceeds muscle protein breakdown, which is a balance regulated, in part, by dietary protein intake.

Adding meal replacement shake to your diet can help you increase your protein intake, thereby helping you build muscle.

Just keep in mind that in order to build muscle, you must also do regular resistance training.

Resistance exercises (like weightlifting) create small tears in your muscle fibers and when your body repairs these tears, your muscles become stronger and larger over time.

What Is the Best Meal Replacement For Weight Gain?

Not all meal replacement shakes are created equal.

Most meal replacements are made from ingredients known to cause painful side effects and even long-term health problems that could impair your ability to gain weight.

Among these ingredients are food additives, dairy-based proteins, and protein concentrates and isolates.

🚫 Avoid Food Additives

Regularly eating food additives can alter the composition of your gut microbiome – the collection of microorganisms living in your gut (North Clin Istanb, 2019).

This can lead to gut dysbiosis, or an imbalance in gut bacteria, which can diminish your ability to digest and absorb the food you eat (Microorganisms, 2022; Microbiome, 2019).

As you might imagine, this can make it hard for you to gain weight.

⚠️ Here is a list of the most common food additives in meal replacements:

• acacia fiber
• acacia gum
• acesulfame potassium
• artificial flavors
• ascorbic acid
• aspartame
• calcium carbonate
• carrageenan
• cellulose gum
• dextrin
• dicalcium phosphate
• dipotassium phosphate
• erythritol
• gellan gum
• guar gum
• gum arabic
• inulin
• locust bean gum
• maltitol
• maltodextrin
• mono- and diglycerides
• ‘natural’ flavors
• rice bran extract
• rice dextrin
• rice hulls
• rosemary extract
• silica
• silicon dioxide
• sodium alginate
• soluble corn fiber
• sorbitol
• soy lecithin
• sucralose
• sunflower lecithin
• tocopherols
• tricalcium phosphate
• xanthan gum
• xylitol
• zinc oxide

Note that this list includes several artificial sweeteners.

Artificial sweeteners like sucralose and acesulfame potassium are among the worst ingredients for your gut microbiome (J Toxicol Environ Health A, 2014).

They both reduce microbial diversity and promote the growth of potentially pathogenic bacteria.

Also note that as a rule of thumb, if you could not find an ingredient in nature or make it at home, it is a food additive.

🚫 Avoid Dairy-Based Proteins

Dairy-based proteins like whey and casein, although not an issue for everyone, can cause digestive issues too.

This is usually because they contain lactose, a sugar many people cannot fully digest.

But you might be sensitive to dairy-based proteins even if you are not lactose intolerant.

This is particularly true for casein protein, which forms a gel-like substance in your stomach that slows down digestion.

🚫 Avoid Protein Concentrates and Isolates

You should also consider avoiding protein concentrates and isolates.

Most meal replacements are made from one or both of these protein sources, which have been mechanically and/or chemically stripped of everything but the protein.

This includes the enzymes, fiber, and other natural digestive aids that help you break them down.

You therefore do not digest them in the same way that you do whole foods, which can affect your gut health.

In fact, studies show that regularly eating protein concentrates and isolates can disrupt your gut microbiome and cause the formation of toxic byproducts in your gut (Nutrients, 2018; Mol Nutr Food Res, 2024).

So instead of ultra-processed protein concentrates or isolates, look for whole food protein sources like egg whites and almonds.

They are easier to digest and absorb.

Order Samples to see for yourself.

Sources

1. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
2. Microorganisms (Microorganisms). Food Additives and Gut Microbiota: A Review on Their Interaction and Possible Health Consequences. 2022.
3. Microbiome (Microbiome). Insights into the role of the microbiome in obesity and type 2 diabetes. 2019.
4. Journal of Toxicology and Environmental Health Part A (J Toxicol Environ Health A). Splenda alters gut microflora and increases intestinal p-glycoprotein and cytochrome p-450 in male rats. 2014.
5. Nutrients (Nutrients). Impact of a High-Protein Diet on the Gut Microbiota: A Comparative Study in Wistar Rats. 2018.
6. Molecular Nutrition & Food Research (Mol Nutr Food Res). Protein Quality Matters: A Review of the Impact of Dietary Protein Quality on Health Outcomes Including Gut Health. 2024.

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This article was written by a Registered Dietitian and reviewed by a Physician Assistant. We rely on peer-reviewed research and trusted medical sources, and regularly update our content to ensure accuracy and clarity.