BY STEPHEN PERRINE

If the only thing you know about whey is that Little Miss Muffet ate it, you’re missing out on an incredibly powerful food that builds lean muscle, fights inflammation, stops fat gain, and heals the gut.

For centuries, whey was considered little more than a cheesemaking by-product—discarded or fed to livestock.

About eighty percent of the protein in milk is casein, which gives us sharp cheddars, smoked goudas, triple-cream Bries, and fancy Pecorino Romanos.

The remaining twenty percent is whey—long overlooked except for the occasional ricotta recipe or pig slop.

But lately, the overlooked sibling has been getting a lot more attention.

Boosting Whole-Body Health

While it’s been a favorite of athletes and bodybuilders for years, more and more research is suggesting that we should all try to make it a regular part of our day. Among its many superpowers, here are six science-backed ways whey boosts whole-body health:

1.) Stops hunger—and keeps it at bay. Studies have shown that whey protein has a stronger satiety effect than other protein, including even whole milk—meaning it will keep you full and satisfied longer. That’s primarily thanks to its high content of branch chain amino acids (BCAAs)—crucial building blocks for muscle.

One specific amino acid, leucine, reaches the brain rapidly after consumption, immediately signaling the appetite to switch off. In fact, leucine has been shown to control both short and long-term appetite.

2.) Build muscle—at any age. Leucine acts like a catalyst for muscle growth, and research shows it’s especially important for adults over forty, when age-related muscle loss tends to accelerate.

But leucine is hard to find in substantial amounts in most foods other than dairy, and whey is far denser in leucine than just about any other food, including its slower-digesting counterpart, casein.

As the late Doug Paddon-Jones, PhD, professor in the Department of Nutrition and Metabolism at the University of Texas Medical Branch, said, “Whey protein is essentially a leucine delivery system that comes in chocolate.”

3.) Bring better health to your belly bugs. Whey is an important component of breast milk and appears to play a significant role in helping infants develop a healthy microbiome and protect against the overgrowth of hazardous microbes like E coli. And that salutary effect is duplicated each time we consume whey as adults.

In one study, researchers examined the effects of whey protein supplementation on the gut microbiomes of both normal-weight and obese individuals. They found that whey stimulated the growth of beneficial probiotic bacteria and increased the production of short-chain fatty acids—without promoting the growth of any bacterial families linked to obesity.

Researchers concluded that whey supplementation “may be an interesting approach to the prevention of overweight and obesity and related disorders.”

In addition, animal studies have shown that the quality of the protein being ingested makes a difference in the quality of the host’s microbiome, and that whey seems to have a more beneficial effect than other types of protein.

4.) Improve your mood and sleep. Whey protein is naturally rich in tryptophan, an amino acid your body uses to make serotonin and melatonin. Serotonin helps regulate mood and appetite, while melatonin is the hormone that tells your body when it’s time to sleep. Together, they help you feel more balanced during the day and more relaxed at night.

In recent studies, whey—especially a form known as alpha-lactalbumin—has been shown to improve sleep quality and boost next-day alertness. In a 2025 study published in the International Journal of Sport Nutrition and Exercise Metabolism, subjects who had trouble sleeping took forty grams of alpha-lactalbumin before bed.

The results?

They fell asleep faster, spent more time in deep, restorative sleep, and performed better on focus and reaction tests the next morning.

A 2023 review of similar studies found consistent results: people who took alpha-lactalbumin in the evening experienced less time lying awake, better sleep quality, and less daytime grogginess—without any side effects.

5.) Lower inflammation levels. Chronic, low-grade inflammation is a hidden driver behind many modern health problems—from insulin resistance and heart disease to joint pain, weight gain, and mood disorders. But whey protein may offer a powerful, natural way to help dial it down.

Whey contains several bioactive components that have been shown to reduce inflammatory markers, support healthy blood sugar, and protect the lining of blood vessels. Among these components are lactoferrin, beta-lactoglobulin, alpha-lactalbumin, and glutathione precursors—all of which contribute to whey’s anti-inflammatory effects.

In a 2022 randomized controlled trial published in Nutrients, overweight and obese adults who consumed thirty grams of whey protein daily for twelve weeks showed significant reductions in C-reactive protein (CRP)—a key marker of systemic inflammation—compared to placebo. The whey group also had improvements in insulin sensitivity and vascular function.

Another meta-analysis published in Clinical Nutrition ESPEN looked at seventeen human trials and found that whey supplementation consistently lowered CRP, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha)—three of the most well-established inflammatory cytokines involved in metabolic and cardiovascular disease.

6.) It boosts your body’s most powerful antioxidant defense. Whey is a natural source of cysteine—a sulfur-containing amino acid that plays a critical role in the production of glutathione—often referred to as the body’s master antioxidant.

Unlike antioxidants we get from food (like vitamin C or E), glutathione is produced inside our cells, where it works around the clock to neutralize free radicals, detoxify harmful compounds, and protect cells from oxidative damage.

Whey’s high cysteine content provides the raw material needed for your body to make more of this essential antioxidant.

In fact, multiple studies have found that regular whey supplementation can increase intracellular glutathione levels—especially in people under oxidative stress, such as older adults, athletes in intense training, or individuals with chronic inflammation.

For example, a 2020 study in Frontiers in Nutrition found that elderly participants who consumed whey protein for twelve weeks had significantly higher blood levels of glutathione and other antioxidant markers, alongside improved immune function.

This is especially relevant because glutathione production naturally declines with age, contributing to increased vulnerability to illness and slower recovery.

Choosing the Right Whey—Concentrate Versus Isolate

Whey protein is typically available in two forms: concentrate and isolate.

Whey protein concentrate contains about seventy to eighty percent protein by weight and retains small amounts of fat, carbohydrates, and lactose.

Because it undergoes minimal processing, concentrate preserves more of whey’s naturally occurring nutrients—such as immune-supportive compounds like lactoferrin and immunoglobulins. It also tends to have a slightly creamier texture and fuller taste, making it a favorite for smoothies and shakes.

Whey protein isolate, on the other hand, is more heavily filtered to remove most of the fat and lactose, yielding a protein content of ninety percent or more. The extra processing makes it a better choice for people with lactose intolerance or dairy sensitivity.

Whey is highly versatile—whether stirred into smoothies, blended into oats, or folded into post-workout shakes. You can also cook and bake with it: liquid whey (left over from straining yogurt or cheesemaking) can be used in pancakes, muffins, breads, and even cookies—anywhere a recipe calls for water or milk.

This not only boosts the protein content of your favorite dishes but also adds a subtle tang and extra tenderness to baked goods, such as pizza!

Looking for a delicious place to start? Try this Whey Pizza recipe for a homemade pie that’s as wholesome as it is satisfying.

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Stephen Perrine is the New York Times bestselling author of The Whole Body Reset, the co-creator, editor and publisher of the Eat This, Not That! book series, and the co-creator of Better Man, a national health and wellness TV show. The former editorial creative director of Men’s Health, as well as the former publisher of Rodale Books, he has appeared on The View, Today, Good Morning America, and more. He currently manages all health and wellness content for AARP Publications.

Well Being Journal adapted the above excerpt from The Full-Body Fat Fix by Stephen Perrine. Copyright © 2024 by Stephen Perrine and used with permission.