Protein Is an Essential Macronutrient, Especially as We Age

Eating protein can fill you up with out filling you out, just one more reason to make sure you eat enough of it. Oleksandra Naumenko/Shutterstock

The headlines behind the macronutrient needs of the body (also called “macros”), which make up carbohydrate, fat, and protein, have been either glorified or demonized over the years. In the 1990s, fat was supposedly the undisputed culprit for heart disease, and at the advent of the 2000s, the Atkins Diet and South Beach Diet had us wary of going anywhere near carbohydrates for fear of weight gain. Fast forward to today, and the pendulum is swinging toward increasing our protein consumption.

Protein Quality

For the most part, Americans have no problem meeting their protein needs, according to the American Journal of Clinical Nutrition. But does it matter what type of protein you consume?

Proteins are considered complete or incomplete depending upon whether they contain the full range of nine essential amino acids. Of the 20 amino acids that make up all protein, the body can create 11. The other nine we need to get from food.

A few plant foods and all animal foods (meat, fish, dairy, and eggs) provide complete proteins. Incomplete proteins from plant-based foods typically lack one or more of these essential building blocks. Fortunately, if we eat a variety of plant foods, we can make up for the shortfall through protein complementation.

For example, beans contain low levels of the amino acids methionine and cysteine, while rice tends to be low in lysine. But if you pair the two of these foods together, they provide all of the essential building blocks the body needs. Soy and quinoa are examples of plant foods that contain all the essential amino acids to form a complete protein.

Protein’s healthy halo is due in part to the feeling of satiety or fullness we feel after eating it. This macronutrient helps us fill up instead of filling out.

Processed foods full of empty calories are devoid of real nutrition and can confer weight gain, whereas protein foods that are more nutrient dense can help us lose weight or maintain our current weight due to that increased satisfaction after the meal.

A study in 2011 examined the differences between carbohydrate and protein calorie yield. While protein provides the same four calories per gram as carbohydrates, researchers posit that it takes about 25 percent more energy to process protein. This means that the calories expended along with the thermic effect of food (energy used to metabolize the protein meal) are higher for protein. So if you eat 100 calories of carbohydrates, that all goes into your bloodstream or fat deposits. But if you eat 100 calories of protein, you get 25 calories burned off in the process of digestion and turning that protein into energy for the body, which means only 75 calories remain to be worked off.

Recommended Protein Intake

Eating protein helps us build and maintain muscle throughout our lives. For the average adult with a healthy body weight, the current recommended dietary allowance (RDA) is 0.8 gram (g) of protein per kilogram (kg) of body weight per day. This is equivalent to 0.36 grams of protein per pound of body weight per day.

Many of us weigh ourselves in pounds (lb.), but don’t let kilograms confuse you: 1 kg = 2.2 lb. Let’s do the math. For example, for a male or female weighing 70 kg (154 lb.), simply multiply (70 kg x 0.8 g/kg) and their consumption would be equal to 56 grams, about the amount of protein in an 8-ounce steak or a four-egg omelet.

If that flashback to the metric system has you feeling a bit uneasy, keep it simple. In order to find out how many grams of protein to consume per day on average, simply multiply your current body weight by 0.36.  Lastly, if you prefer to look at protein intake as a percentage of your total calories for a given day, then use the Average Macronutrient Distribution Range (AMDR) which allows for 10 percent to 35 percent of calories from protein foods.

For example, if your goal is to adhere to a 2,500 calorie per day diet and you wish to keep protein intake at 15 percent, simply make the percentage into a decimal: .15 x 2,500 = 375 calories from protein per day.

Not everyone shares the same goals when it comes to eating protein. According to a June 2017 position statement by the International Society of Sports Nutrition, “For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4–2.0 grams of protein per kilogram of body weight is sufficient for most exercising adults.”

The American Academy of Nutrition and Dietetics suggests 1.2 to 1.7 g/kg for endurance athletes and 1.4 to 1.8 g/kg for strength training. A 2011 study notes that for healthy adults, 2 grams is the maximum amount of usable protein by the human body, and there is no benefit to consuming more.

It’s worth noting that for those who over consume protein and for those who are mostly sedentary, eating more protein wouldn’t necessarily provide any additional benefit based on lifestyle.

Age and Gender

Research done in 2017 suggests that there are no differences in protein recommendations between genders. However, researchers note that more studies need to be examined based on strength training in females. When it comes to age and protein needs, there is some variation.

According to the American Academy of Nutrition and Dietetics, protein intake is of particular concern as we age, as about 50 percent of women and 30 percent of men 71 and over aren’t meeting the RDA.

Furthermore, a number of studies demonstrate that eating slightly more protein (approximately 1.0 to 1.5 grams) in adults older than 65 years can reduce the loss of lean body mass that occurs with age. When combined with strength training, this may help to reduce the risk of illness and death.

The American Academy of Nutrition and Dietetics further states that consuming 25 to 30 grams of protein at each meal slows age-associated loss of muscle mass and improves gains in muscle mass owing to strength training in older adults.

To the contrary, results from the National Health and Nutrition Examination Survey (NHANES) indicate that for middle-aged adults (ages 50 to 65), higher protein intakes don’t offer added benefit.

In this age group, consuming protein as recommended by the RDA (0.8 g) has been found to be more beneficial in preventing cancer, overall death, and possibly diabetes. Further, this amount of protein is significantly less than most U.S. adults currently consume.

Research into the health benefits of both a higher protein intake in older adults and a lower protein intake for middle-aged adults is being examined based on consuming more plant-based foods.

Final Takeaway

Next time you visit the grocery store consider variety, balance, and adequacy, especially when it comes to protein. If you are eating chicken only, you may be missing out on the omega-3s in fish or the fiber in chickpeas (hummus); both of which are excellent sources of protein.

Secondly, though it’s fine to swig down a protein shake post-workout, shakes won’t be as satiating as eating protein in its whole form. This goes back to the thermic effect of certain foods. The body has to work much harder to process a steak than it does a shake, which means that you will feel fuller longer with solid protein foods.

Finally, as enticing as protein-infused animal crackers sound, they don’t have enough protein to matter. Moreover, they are replete with added sugars. Therefore, buyer beware.