How to Find the Best Protein Powder for Kids’ Weight Gain

📌 Overview and Key Takeaways

This is a Dietitian’s guide on how to find the best protein powder for kids’ weight gain​.

Discover how to help kids safely supplement their protein intakes.

Last Updated
Feb 3, 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.

Protein Powder for Kids’ Weight Gain

Is Protein Powder Good for Kids?

If your kid is a picky eater, or just small for his or her age, you may be wondering if supplementing his or her diet with protein powder is a good idea.

Frankly, most kids, even the pickiest of eaters, do not need protein powder – they should be able to get all the protein they need from foods like eggs, fish, and meat.

Some kids, like those with dietary restrictions, might benefit from a protein supplement, however.

In fact, research shows nutritional supplements like protein powder can promote catch-up growth in some cases (Nutrients, 2021).

Protein powder is helpful because it can be mixed with just milk or water, added to smoothies, oatmeal, and other recipes.

This convenience and versatility is hard to beat.

Keep in mind that the Dietary Reference Intake for protein for children aged 4-13 years is 0.95 grams per kilogram of body weight per day (Nutrients, 2021).

For most kids, this translates to 15-40 grams of protein per day.

Can Protein Powder Help a Kid Gain Weight?

For a kid to gain weight, he or she simply has to eat more calories than she or he burns.

It takes an extra 3,500 calories to gain a pound, and to gain weight at a safe rate (0.5 pound per week), a kid needs to eat an extra 250 calories every day.

Moreover, if you would like your kid to not only gain weight, but also to build muscle, then he or she has to eat protein.

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

Adding a protein powder to your kid’s diet is an easy way to increase both calorie and protein intake, thereby helping him or her gain weight and build muscle.

That said, not all protein powders are created equal.

What Is the Best Protein Powder for Kids’ Weight Gain?

Any type of protein powder (egg white, pea, whey, etc.) can help a kid meet his or her daily protein needs.

In other words, as long as he or she is eating a balanced diet – getting protein from a variety of sources – there is no advantage to using one type of protein powder over another.

Ingredients do matter, however.

Most protein powders contain ingredients known to cause painful side effects and even long-term health problems.

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

🚫 Avoid Food Additives

Regularly eating emulsifiers, thickeners, and other ultra-processed additives can not only upset a kid’s stomach, but also alter the composition and function of his or her gut microbiome (North Clin Istanb, 2019).

These shifts, known as gut dysbiosis, have been shown to contribute to the development of several chronic diseases, including allergies, asthma, and obesity (Microb Ecol Health Dis, 2015).

Dysbiosis is so problematic because it causes a cascade of problems, including intestinal permeability, systemic inflammation, impaired nutrient absorption, and reduced short-chain fatty acid (SCFA) production.

⚠️ Here is a list of the most common food additives in protein supplements:

• 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

As a rule of thumb, if you cannot find it in nature or make it at home, it is probably a food additive.

🚫 Avoid Dairy-Based Proteins

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

This is usually because they contain lactose, a sugar many individuals with sensitive stomachs 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

Kids might also want to avoid ultra-processed protein concentrates and isolates.

Most protein supplements are made from one or both of these ultra-processed 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 your gut break them down.

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

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

You should thus look for protein supplements made from whole food protein sources like egg whites and almonds, which are easier to digest and absorb.

Order Samples to see for yourself.

Sources

1. Nutrients (Nutrients). Oral Nutritional Supplementation Improves Growth in Children at Malnutrition Risk and with Picky Eating Behaviors. 2021.
2. Nutrients (Nutrients). Dietary Protein Requirements in Children: Methods for Consideration. 2021.
3. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
4. Microbial Ecology in Health and Disease (Microb Ecol Health Dis). Dysbiosis of the gut microbiota in disease. 2015.
5. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
6. Molecular Nutrition & Food Research (Mol Nutr Food Res). In Vitro Fermentation of Animal and Plant Protein Isolates by the Human Gut Microbiota Under High and Low Carbohydrate Conditions. 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.