Why Your Body Needs Protein
Proteins are made of smaller building blocks called amino acids. When proteins are digested into amino acids and absorbed, the amino acids are used to create new proteins in the body. These new proteins have crucial roles to keep the body functioning, including building and repairing tissues, supporting bones, immunity, and metabolic functions.
There are 20 amino acids. Nine amino acids are considered “essential” because the body cannot make them, and they must come from the diet. Not all foods have every amino acid, so it’s important to include various types of protein in the diet. Protein needs vary by individual, and higher amounts may be beneficial to support different goals at different life stages.
How Much Protein Do I Need?
The current Recommended Dietary Allowance (RDA) for adults is 0.8 grams of protein per kilogram of body weight per day. This represents the minimum amount needed to avoid deficiency, not necessarily the optimal intake for health, performance or aging well.
Some groups of people can benefit from higher amounts of protein, including those who exercise regularly, older adults and vegetarians or vegans. Adults who exercise regularly may need 1.4–2.0 g/kg daily to support building or maintaining muscle, with endurance sports on the lower end of the range and resistance activities on the higher end.
- Middle-aged and older adults are advised to consume 1.0–1.2 g/kg, ideally 25–30 grams per meal to help maintain strength and combat age-related muscle loss. Muscle mass can begin to decline by roughly 1% per year by middle age, with factors like low protein intake, rapid weight loss and inactivity accelerating this decline.
- Vegetarians and vegans can also benefit from at least 1.0 g/kg to account for differences in protein quality and digestibility between animal and plant food sources.
For a deeper dive into how protein supports aging, see Mind Your Protein Now. It Will Matter as You Age.
Understanding Types of Proteins
Complete vs. Incomplete Proteins, Explained
The concept of complete vs. incomplete proteins has to do with amino acids. Animal proteins such as meat, dairy and eggs are considered “complete” because they contain all nine essential amino acids in the amounts the body needs. Plant proteins are often classified as “incomplete” as most are lower in one or more essential amino acids. For instance, grains, tend to be low in lysine, while legumes are often low in methionine.
With some planning, a combination of plant proteins can meet amino acid needs. For example, pea protein is low in methionine while rice protein is low in lysine. When consumed together, they form a balanced amino acid profile. Soy is one of the few plant sources that is considered complete, offering all nine essential amino acids.
You don’t need to stress about every meal; what matters is variety and balance throughout the day. A diverse plant-forward diet can meet all amino acid needs.
What Is Protein Digestibility?
Digestibility also matters when considering types of protein. Using the Digestible Indispensable Amino Acid Score (DIAAS), which evaluates the digestibility of each essential amino acid, animal proteins generally rank as “excellent” (scores ≥100), while many whole plant proteins fall below that range. Plant foods can be harder to digest because they contain fiber and natural compounds like phytates that slow absorption. However, when plants are transformed into isolates like soy or pea protein powders, their digestibility and DIAAS scores improve.
Can Plant Protein Build Muscle?
A common myth is that plant proteins cannot build muscle. Prospective studies show that when total protein intake is sufficient along with a resistance training program, muscle and strength gains are the same with soy or animal protein. The key is eating enough, ideally from varied foods that provide a complete amino acid profile. Supplements can also help fill in protein gaps on a plant-based diet.
All About Dairy Proteins
Dairy contains multiple types of protein. Whey, one of the proteins found in dairy, digests rapidly, raising blood amino acid levels quickly over a short period of time. This makes dairy protein ideal after exercise when muscles are primed for repair.
Casein, on the other hand, digests slowly and releases amino acids gradually over several hours. This steady supply makes it especially useful before bed, when it can help reduce overnight muscle breakdown. Together, whey and casein provide a powerful combination for athletes, active individuals and older adults trying to protect muscle health.
Abbott’s dairy-based nutrition shakes contain both whey and casein (fast and slow-digesting proteins). Within the Ensure Max Protein portfolio, these high-quality proteins work together to provide a steady supply of amino acids that feed muscles for up to 7 hours.
Smart Strategies: Your Protein Game Plan
Aim for Variety
The best approach to protein intake is to aim for variety and balance, rather than relying on one protein source alone. Combining different types of protein allows you to take advantage of the unique benefits of each. For those following a plant-based diet, this is especially important and pairing complementary proteins, such as grains and legumes, helps ensure a complete amino acid profile.
Optimize Timing
Spread protein intake evenly throughout the day. Most people can aim for 20 to 30 grams per meal to maximize absorption and maintain muscle. Certain groups, like athletes or older adults, may have higher protein needs and require a higher protein goal.
Supplement With Intention
Protein supplements, whether dairy or plant-based, can be a useful tool to help fill nutrition gaps and support overall protein intake. These may be especially helpful for athletes, older adults or anyone recovering from illness when appetite is a challenge or when whole foods alone aren’t enough. Consider options like Ensure, which provides convenient, ready-to-drink formulas in both dairy and plant-based varieties to support different preferences and nutritional needs.
