CHICAGO — It’s been 46 years since movie protagonist Rocky Balboa downed a glass of raw eggs before his pre-dawn morning run ending atop the steps of the Philadelphia Museum of Art. While it may have been rudimentary — and a food safety violation — the performance-enhancing beverage was a form of sports nutrition. Today, the category has advanced significantly as food and beverage product developers continue to formulate products to benefit both professional athletes and amateurs.

Such active nutrition products are formulated to readily be incorporated into one’s daily routine. Many focus on the traditional sports nutrition principles of fueling, hydration and recovery, while a growing number include functional ingredients to differentiate in the marketplace.

The eggs Rocky consumed provided the protein he needed for performance and recovery. Athletes know protein provides the power they need to perform.

“Consuming adequate amounts of protein is critical for supporting health and performance,” said Eric Ciappio, strategic development manager-nutrition science, Balchem Corp., New Hampton, NY.

It’s not just adequate amounts, as all proteins are not created equal. Complete proteins contain all the essential amino acids in the amounts required by the body. Proteins that do not contain enough of one or more essential amino acids are called incomplete.

Then there’s protein quality to consider. This measurement factors in completeness, as well as digestibility.

“It’s important to achieve a high enough protein target for sports recovery, either multiple servings of lower amounts of protein (10 grams) or a single serving of a higher level of protein (20 to 30 grams),” said Aaron Martin, director of nutrition innovation, Agropur, Appleton, Wis. “Either way, it’s important to consume enough protein in a single sitting to maximize protein’s impact.”

Data indicate humans need about the same amount of dietary protein every day for basic lean muscle repair and remodeling, said Donald Layman, PhD, professor emeritus of nutrition at the University of Illinois at Urbana-Champaign. To reap other benefits — those for optimum performance — one must consider the quality of the protein and the quantity of the protein at every meal, in particular breakfast.

He said research shows each meal should include 30 grams of high-quality protein, including protein that is high in the branched-chain amino acid (BCAA) leucine. Of all the protein ingredients available to food and beverage manufacturers, whey protein isolate contains the most leucine — 11%. Milk protein concentrate comes in second at 9.5%, followed by egg protein at 8.8%.

Proteins vary in their individual amino acid composition and their level of amino acid bioactivity, among other attributes.

Products that carry a “good source of protein” claim must provide more than 10% of the Daily Value (DV) of protein per serving, while those making an “excellent source of protein” claim must contain more than 20% DV. That does not simply translate to 5 grams and 10 grams of protein per serving. It’s 5 grams and 10 grams of “high-quality” protein.

The DV for protein is determined using the Protein Digestibility Corrected Amino Acid Score (PDCAAS), which is an adjustment for the quality of the protein. It is based on the types and amounts of amino acids in the food, as well as the overall digestibility. The PDCAAS values range from 0.0 to 1.0, where values are truncated to a maximum score of 1.00, which cows’ milk, casein, whey, eggs and soy protein all possess.

Most plant protein sources have much lower values. Thus, a yogurt beverage containing 10 grams of milk protein may make an “excellent source of protein” claim. A cultured vegan product with 10 grams of protein from pulses or grains most likely only qualifies for a “good source of protein” claim. When making or implying any protein content claim, the Food and Drug Administration requires the inclusion of the %DV to support the protein claim.

From a functional perspective, dairy and plant proteins vary, too. Functions include water-binding capacity, viscosity, heat stability and gel strength. Flavor differences also exist, with plant proteins often described as beany, earthy and sour, while dairy proteins are described as milky, soapy and sweet.

Cows’ milk contains two types of proteins: casein and whey. Casein remains in the curd during cheesemaking while whey is washed away in the liquid stream after curd draining. Both are considered high-quality proteins. Their primary difference is in how they are digested. Whey proteins are digested much faster than casein proteins. On the plant side, soy proteins also are digested slowly.

To provide noteworthy levels of protein in performance products, formulators often blend them. Bolthouse Farms, Bakersfield, Calif., does this with its Bolthouse Farms Protein Plus Shake. A 15.2-oz bottle contains 30 grams of protein from reduced-fat milk, soy protein concentrate and whey protein concentrate. The company explains on the side panel that “whey is absorbed quickly to satisfy immediate nutrition needs while soy protein absorbs at a lower rate for sustained benefits.”

“Protein remains a huge draw in the sports nutrition space as consumers associate the nutrient with a raft of positives, including muscle-building, weight management, satiety and recovery speed,” said McKenna Mills, senior technical services specialist at Cargill, Minneapolis. “Soy and whey proteins remain widely popular in formulations, but alternative plant-based proteins are also gaining ground.

“Pea protein, in particular, is well-suited for sports nutrition applications. It offers very good protein content and is high in leucine. While pea protein contains all the essential amino acids, it is not a complete protein because two of the amino acids, methionine and cysteine, are present in relatively low amounts. To compensate, formulators can blend pea protein with a complementary protein source to make complete protein claims. Another option is to add extra pea protein to hit the target protein claim.”

New York City-based Spare Food Co. now offers Spare Tonic, which is made from upcycled whey. The beverage is rich in electrolytes, including calcium, magnesium and potassium, and is an excellent source of vitamins B6 and B12. It has a natural 3:1 carbohydrate-to-protein ratio, which makes it effective as a post-workout recovery beverage.

PB2 Foods, Tifton, Ga., is launching PB2 Performance Plant Pre-Workout products to its line. Formulated to improve a person’s training routine with a boost of caffeinated energy from coffee berries and 10 grams of complete protein from a blend of roasted peanut powder and brown rice protein, the no-added sugar beverage mix is sweetened with monk fruit.

The Tart Cherry High Intensity Blend has a vegetable blend base, while Raspberry Endurance Blend includes medium chain triglycerides (MCT). Both products are vegan, non-GMO and gluten-free with no artificial ingredients.

“Pre-workout products currently on the market tend to be supplements with lots of caffeine,” said Craig Entwistle, chief executive officer. “We dial back on the caffeine. One serving contains the equivalent of about one cup of coffee. We then add clean, plant-based protein. We’ve created a pre-workout superfood that is ideal for athletes of all types.”

Adding energy ingredients

Fueling the body with energizing nutrition has become popular in the sports nutrition space. One approach is by adding metabolic energy, which refers to the Krebs cycle, a complex pathway that converts ingested carbohydrates, fats and proteins into a steady stream of energy — adenosine triphosphate (ATP) — during the process of aerobic respiration. This energy fuels the body’s cells to keep the body working, with the unit of energy measured in calories.

Several non-essential amino acids involved in producing ATP often are added to performance products. The amino acids include citrulline, acetyl L-carnitine and creatine.

Many B vitamins are known to participate in this energy-producing process. They are not metabolized, and thus do not contain calories and are not energy. Still, because they are critical components in the Krebs cycle, they often are included in sports nutrition products.

Caffeine is also calorie free, and therefore not metabolized. It functions by attaching to receptors on brain cells, stimulating the brain and thereby increasing mental alertness. Consumers perceive this as being a boost in energy, but in fact, it has nothing to do with providing caloric fuel to the body’s working cells.

Alternative Biologics Inc., Benicia, Calif., which developed Muscle Milk, is introducing Gym Weed, a line of hemp-infused performance drinks. Gym Weed is said to provide balanced energy without the jittery, anxious feeling typically associated with such drinks. A 12-oz can contains no sugar and 10 calories, along with 20 mg of hemp extract, 200 mg of caffeine, 100 mg of lion’s mane and 100 mg of L-theanine, plus B-vitamins and electrolytes.

“We created Gym Weed to give people an energy drink that actually makes you feel good to help you power through your toughest workouts,” said Shane McCassy, president. “Throughout its development, we sent samples to industry-leading trainers and athletes. What we learned is what we claim: It tastes great, and it provides the energy and focus athletes want when hitting the gym, without the jitters or crash.”

Gatorade, a brand of PepsiCo, Inc., Purchase, NY, is launching Fast Twitch. Each 12-oz bottle contains 200 mg of caffeine, electrolytes and B vitamins.

“At Gatorade, we’ve spent decades studying the best athletes in the world, and what we’ve learned is there hasn’t been an athletic energy solution they can trust that is designed for them to start fast and ignite their performance,” said Anuj Bhasin, vice president of marketing and general manager for Gatorade. “We’re thrilled to change that with the launch of Fast Twitch, the first-ever caffeinated energy drink from Gatorade, designed for athletes in every way, from formula to design and packaging.”

Guarana extract is a common source of caffeine. Obtained from the seeds of the guarana plant’s fruit, the seeds are a more concentrated source of caffeine than coffee beans.

Ginseng is a caffeine-free stimulant obtained from more than a dozen species of ginseng plant. The roots of the plant contain an array of nutrients, including antioxidants, vitamins, minerals and intriguing compounds called ginsenosides. It is these ginsenosides that are believed to have a stimulating metabolic effect on the central nervous system and provide a powerful boost to energy and stamina.

Similar to a vitamin, coenzyme Q10 functions as an antioxidant. It is used by cells to produce the energy that the body needs for cell growth and maintenance and helps sustain heart health and blood pressure.

When it comes to metabolic energy, not all carbohydrates, fats and proteins are metabolized the same. For example, MCT oils are said to fuel the body with a sustained, clean energy that satiates appetite and reduces cravings. The oils also have been shown to provide a cognitive boost, support fat burning and balance mood and hormone levels.

Carbohydrates such as isomaltulose provides a sustained source of energy. Derived from sugar beets, isomaltulose is a fully digested carbohydrate, but it is digested more slowly than other sweeteners, resulting in a full supply of energy from glucose over a longer period of time. Being low-glycemic, it releases energy the balanced way without sudden peaks and drops of the blood glucose level.

Isomaltulose also has been shown to promote the body’s own fat oxidation, which means that it increases the ratio of energy derived from fat relative to the total amount of required energy while active, leaving carbohydrate stores available for longer.

Ribose, a naturally occurring sugar made in the body from glucose, also accentuates the body’s natural process of energy synthesis. Ribose helps to reduce the loss of energy during stress and accelerates energy and tissue recovery. Through this action, ribose helps muscles regenerate lost energy and potentially minimizes any physiological consequences of this energy depletion situation.