Of the three macronutrients—protein, carbohydrate, fat—the only one to maintain a steady health halo through the years is protein. Carbohydrate and fat have shared the negative nutrient spotlight, but protein has escaped that wrath. And today, more than ever, protein is standing strong.
The importance of getting ample, quality protein is a message you’ll see promoted on everything from milk cartons and cereal boxes to baking mixes, packaged snacks and even marshmallow treats! And nutritional powders are a popular, convenient way to get a healthy dose of protein from a variety of sources, including animal- to plant-based ingredients.
Researchers and nutrition experts talk about protein quality using PDCAAS, which is short for the Protein Digestibility Corrected Amino Acid Score. This scale compares the amino acid profile of a protein source with the essential amino acid requirements that people need. The PDCAAS is the official protein-quality measure adopted by everyone from the World Health Organization to the FDA. The gold standard is egg whites, which have a score of 1.0. Soy and whey also rate a 1.0. Some of the newly popular plant proteins, however, fall a little short. Pea protein comes in at 0.7, rice protein at 0.5 and hemp protein at 0.46, for example, because they are missing some of the essential amino acids found in animal products.
People looking for a workout boost tend to rely on protein because it breaks down to amino acids, which are the building blocks of muscle, making protein useful for exercise recovery. How fast the amino acids are absorbed and available, however, varies depending on what kind of protein you’re eating.
The king of protein powders
In supplement aisles, the king of protein powders has long been whey protein, a byproduct of making cheese. Whey is the favored protein source of bodybuilders and other fitness aficionados, and not just because of its smooth flavor and texture.
Whey is known as a “fast” protein because we digest it relatively quickly—between 30 and 60 minutes after eating, according to protein researcher Blake Rasmussen, PhD, at the University of Texas Medical Branch. Casein, a different dairy protein, is a “slow” protein, because it requires three to five hours to digest. Soy and rice proteins are considered “intermediate” proteins because they take between one and two hours to digest.
Besides building muscle, protein can also help you manage weight because it can make you feel fuller longer. A study by Nestle researchers found drinking a protein drink containing 20 grams of protein 30 minutes before a meal reduced the amount of calories consumed at the ensuing meal—but this was true only for casein and pea protein, not so with whey or egg. That means slower-digesting proteins are better for feeling satiated. All protein sources, however, worked to cut the blood sugar–raising response of the meal. Researchers also tested giving the study subjects the protein drink at the start of the meal and found no difference in the amount of food they ate.
Plant proteins and blends.
Soy is still the most commonly used plant protein by supplement makers, but other plant sources—from rice and pea to hemp and spirulina—are quickly growing in consumer appeal. Plant proteins could become the protein of the future, especially with climate, health and sustainability issues related to raising livestock. Even so, most tasters still prefer the silky, frothy taste of whey compared with the more gritty texture of some plant proteins.
A breakthrough study from 2012 using a blend of different protein sources—50 percent casein, 25 percent whey, 25 percent soy—found the blend was superior to whey alone for prolonging muscle building and improving recovery after exercise.
“The combination gives you a quick increase in protein synthesis, and it gets sustained,” Rasmussen says. “It’s a prolonged delivery to muscle that the muscles use for recovery.” As a result, you can now find many protein powders that combine a number of protein sources, as well as those that add in other beneficial ingredients, such as fruit and vegetable powders, dehydrated nut milks, collagen and more.