CHICAGO — Eat to run and run and eat. Hectic lifestyles have a growing number of consumers relying on nutrition shakes, the marketing term increasingly being used to describe meal-replacement beverages. Once thought of as a weight-loss tool, for replacing a meal to prevent overconsuming calories, today’s new generation of drinkable meals are more often designed to help “on the go” consumers fuel with all the nutrients the body needs for peak performance.

Many emerging meal-replacement beverages are designed for specific demographics. These may include children and athletes, as well as adults following lifestyle diets, such as keto, paleo and vegan.

Gatorade Nutrition Shakes from PepsiCo, Inc. were formulated with the nutritional needs of active adults in mind. An 11-oz bottle contains 370 calories, 20 grams of milk protein, 8 grams of fat and 54 grams of carbohydrates. This balanced sports nutrition is for recovery and training.

The drink provides immediate sustainable energy. The enhanced protein content increases net muscle protein synthesis and speeds recovery and stimulates growth of muscle. The drink does all this while delivering the vitamins and minerals the body expects in a balanced meal.

Abbott Laboratories, Abbott Park, Ill., offers a range of nutritional beverages designed for the needs of children. PediaSure Grow & Gain provides complete balanced nutrition, as it is formulated to help children who are at nutritional risk for proper development. PediaSure SideKicks, on the other hand, help parents of picky eaters fill nutrition gaps. The ready-to-drink snack-size shakes have 40% more protein and 25% fewer calories than PediaSure Grow & Gain. They feature macronutrients and 25 vitamins and minerals.

Mainstream meal-replacement beverages increasingly emphasize the inclusion of whole foods. They will contain healthy fats, protein and carbohydrates, along with a variety of vitamins and minerals, much like one would consume in a well-balanced meal. Most emphasize a low added sugar content, recognizing that many consumers are interested in reducing sugar consumption as part of their overall balanced diet.

Ready-to-drink beverages are the ultimate in convenience, but drink mixes in the space continue to grow. Some consumers find the mixes to be eco-friendly, as they have long ambient shelf lives and minimal packaging. Dry mixes also allow for the inclusion of more specialty ingredients, as they remain encapsulated — and therefore protected — until hydration.

Protein always has been one of the prominent “good things” in meal-replacement beverages, as protein is vital to health and well-being. It is associated with muscle development, energy, satiety and weight management.

Not all proteins are alike, however, as they vary in amino acid composition and their level of amino acid bioactivity, among other attributes. Meal-replacement beverage manufacturers are starting to promote protein sources in order to differentiate by nutritional value.

“High-quality proteins” are those that are readily digestible and contain the dietary essential amino acids in quantities that correspond to human requirements. Currently protein quality is measured 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 ranges from zero to 1.0. Cow’s milk, casein, whey, eggs and soy protein all score the maximum 1.0. Most plant protein sources have much lower PDCAAS values.

The PDCAAS values are not to be confused with the term “complete protein,” which defines proteins that contain all nine essential amino acids and may be fully utilized by the body during the protein synthesis. Animal proteins are complete, as are soy and quinoa. Most other plant proteins are not complete.

Nutrition Facts Labels indicate the grams of protein per serving; however, the Percent Daily Value (D.V.) is determined using the PDCAAS. The PDCAAS is the basis for protein content claims. For a product to carry a “good source of protein” claim, it must provide more than 10% D.V., which equates to more than 5 grams of high-quality protein per serving. To be an “excellent source of protein,” a serving must contain more than 20% D.V., or more than 10 grams.

Protein claims are almost always a part of marketing meal-replacement beverages. When making or implying any protein claim, the U.S. Food and Drug Administration requires the inclusion of per cent D.V. for protein in the Nutrition Facts Label. This is proof of protein claim.

For example, one nutrition shake may contain 10 grams of protein from whey and soy while another contains the same amount of protein from peas and nuts. The first one may make an “excellent source of protein” claim. A plant protein-fortified beverage most likely only qualifies for a “good source of protein” claim, and when doing so, it is wise to not flag 10 grams of protein per serving, as this figure may be misleading.

Providing long-lasting energy

Effective meal replacements fuel consumers with energy, keeping them charged for three to four hours. Protein contributes “metabolic” energy in the form of calories, as do carbohydrates and fats. Better-for-you fats, such as medium-chain triglyceride (M.C.T.) oils from grass-fed butter and coconut, are being embraced as a source of sustained, clean energy that satiates appetite and reduces cravings. The M.C.T. oil also has been shown to provide a cognitive boost, support fat burning and balance mood and hormone levels.

SlimFast, a nationally recognized weight-loss brand of nutrition shakes and other meal-replacement products, has created the SlimFast Keto line. It includes two meal-replacement shake mixes made with a balanced amount of high-fat, low-carb, moderate-protein keto diet-compatible ingredients, including grass-fed butter, coconut oil, M.C.T.s, and protein from whey and collagen.

New Bear Squeeze is a performance-driven meal shake that is paleo, vegan and keto friendly with five grams of net carbohydrates. The product comes as a dried powder in a plastic bottle to which water or a milk alternative is added. Milk may be added if the vegan or paleo attribute is not important. The dry nutrient blend includes coconut oil, kale, pumpkin seed protein, vitamins and minerals.

For “stimulating” energy, many meal-replacement shakes are including natural sources of caffeine, such as coffee and tea, or pure caffeine. Caffeine is not metabolized and therefore calorie free. 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.

SlimFast’s SlimCafé comes in mocha macchiato and caramel cappuccino flavors. Crafted from brewed coffee and milk, the nutrition beverages have no added sugar and 10 grams of protein. With 120 calories, they are more of a snack beverage than a meal replacement.

The benefits of digestive health

Fiber, recognized for its satiating properties, long has been included in meal-replacement beverages. To maintain palatability, fiber often is added through multiple sources, including fruits, vegetables, whole grains and isolated fiber ingredients. With digestive health now mainstream, many marketers are focusing on the inclusion of prebiotic fibers, often with the addition of probiotic cultures.

New York-based Choopoons is introducing Simply Free. The drinks function as on-the-go mini-meals or snacks with under 200 calories and 10 grams of protein. They are made from simple ingredients and include probiotic cultures. Chia seed oil provides omega-3 fatty acids while acacia fiber is a prebiotic that fuels the probiotics. Cucumber seeds are a source of protein. The 12-oz perishable beverages come in banana cinnamon, cold brew, mango and strawberry varieties. Sweetened from cacao fruit pulp rather than refined sugars, the product qualifies for a no-added-sugar claim.

Sneakz Organic, Jupiter, Fla., has added Meal2Go complete nutrition shakes for adults to its line of whole food blended meal supplement and replacement drinks. Boasting a full serving of daily vegetables, Meal2Go combines 16 grams of plant protein, 17 vitamins and minerals, ancient grains, quinoa, ashwagandha and probiotics. The dry beverage is prepared by mixing with 8 to 10 oz of milk or water to create a smooth, shake-thick consistency.

Sneakz Meal2Go made its debut in cinnamon chocolate, cinnamon vanilla swirl and roasted coffee blend varieties, which were taste- and performance- tested among active adults, athletes and scientists. Every flavor contains whole carrots, cauliflower, sweet potatoes, beets, spinach and kale.