As modern life becomes busier and busier, many of us turn to quick, convenient meals often loaded with carbohydrates. From sugary breakfast cereals to starchy snacks, our Westernised diet has become heavily reliant on carbohydrates, often at the expense of protein—a critical, usually under-consumed nutrient. But at what cost? The price may be steeper than you think, especially when it comes to our longevity and overall health.
The Power of Protein
Protein isn’t just another nutrient; it’s the building block of life. Skeletal muscle, which makes up about 40% of our body, is the largest organ in the body—yes, even larger than your skin! The quality of your skeletal muscle significantly impacts your longevity and vitality.
After the age of 30, we begin to lose muscle mass at a rate of 3% to 8% per decade, a rate that accelerates even further as we age 1.
Sarcopenia, or the gradual involuntary loss of skeletal muscle tissue as we age, is a key factor contributing to functional decline and a loss of independence in older adults2. Sarcopenia is caused by several factors, including loss of neuro functionality, hormonal changes, inflammation, decreased physical activity, chronic illness, and poor nutrition. In addition, fat infiltration into skeletal muscle caused by obesity can result in a phenomenon known as sarcopenic obesity, which translates to excess body weight and not enough muscle mass2 .
To counteract muscle loss and maintain a high quality of life, two things are essential: consuming adequate amounts of good-quality protein and engaging in resistance training. But why is protein so important, and how can it help us live longer and healthier lives?
The Importance of Protein for Muscle Mass and Longevity
Proteins are composed of amino acids (AAs), the building blocks that perform a myriad of functions in our body. Of the twenty AAs, nine are essential, meaning they must be obtained through our diet. Among these essential AAs, three stand out: Leucine, Isoleucine, and Valine—collectively known as branched-chain amino acids (BCAAs). These BCAAs are vital for activating protein synthesis, the process that fuels and maintains muscle mass.
Without sufficient BCAAs, our bodies cannot effectively build or maintain muscle, making adequate protein consumption crucial, particularly as we age. While BCAAs are essential for activating protein synthesis, it’s important to remember that consuming all nine essential AAs is necessary for this process to function optimally. Neglecting the other six AAs can impair protein synthesis, no matter how much BCAAs you consume. For instance, someone who relies on BCAA supplements while neglecting a healthy, protein-rich diet will not achieve adequate muscle maintenance or growth. This is why protein shakes (usually containing BCAAs) should be viewed as a supplement to a well-balanced diet, not a replacement for it.
Recommendations for protein consumption
The current Recommended Nutrient Intake (RNI) for protein in the UK is 0.75 grams per kilogram of body weight. For instance, if you weigh 60 kg, your daily consumption of protein, based on RNIs, would be 45 grams per day. However, this is merely a baseline to avoid deficiency, not an optimal amount for maintaining or building muscle mass and promoting longevity, especially for adults in midlife and older adults. For those, consuming between 1.2 to 1.6 grams per kilogram of body weight is more beneficial for muscle synthesis, helping to slow down muscle mass decline and support healthy ageing3.
Research has demonstrated that increased protein intake, when combined with resistance training, plays a key role in preserving both strength and muscle mass. For individuals aiming to lose weight, consuming around 1.6 grams of protein per kilogram of body weight helps maintain muscle mass while promoting fat loss3. Conversely, insufficient protein intake, even in the context of a calorie deficit, leads to the loss of both fat and muscle, compromising overall strength and body composition. Moreover, protein synthesis seems to be more efficient when protein is consumed evenly during all three meals throughout the day 4,5.
Prioritise Protein Over Carbohydrate
A good reason for eating more protein and fewer carbohydrates is that protein keeps us feeling fuller for longer. This is partly explained because carbohydrates, especially the simple types, are quickly broken down into sugars and easily digested, conversely to protein. Ever notice that when you eat a plate of white pasta for lunch, you might feel hungry again a couple of hours later?
In addition, a phenomenon called “the protein leverage hypothesis” suggests that when our bodies don’t get enough essential AAs, we continue to crave food, searching for those missing nutrients. For instance, a bowl of cereal in the morning may leave you reaching for a doughnut by mid-morning. On the other hand, a protein-rich breakfast can keep you full and satisfied for much longer.
Protein also has a higher TEF (Thermic Effect of Food) compared to carbohydrates and fats, meaning it takes more energy for our bodies to digest protein compared to their macronutrient counterparts. This process can use up to 20% of the calories consumed in protein-rich foods, compared to just 5% to 15% for carbohydrates. So, when you eat a 300-calorie steak, your body might use up 60 of those calories just to digest it, while the same amount of white pasta might only require 15 calories for digestion. This not only helps with weight management but also keeps your metabolism more active.
What Are Good Quality Proteins?
Not all proteins are created equal. “Complete” proteins contain all nine essential AAs that our bodies cannot produce on their own. Animal-based sources such as meat, fish and eggs are prime examples, while plant-based options include quinoa, chia and hemp seeds, lentils as well as some soy products such as tempeh and tofu. However, plant sources like quinoa come with a significant carbohydrate load, and you would need to consume an impractically large amount to match the protein content of, say, a piece of chicken. This makes it more challenging for vegetarians and vegans to meet their protein needs without overconsuming carbohydrates. As a result, plant-based diets require extra planning and nutritional awareness to ensure adequate protein intake.
The Role of Resistance Training
While diet plays a crucial role in maintaining muscle mass, it’s only one piece of the puzzle. Resistance training—such as weight lifting, bodyweight exercises, or resistance band workouts—is equally important. This type of exercise stresses the muscles, encouraging them to grow stronger and more resilient. When combined with an adequate protein intake, resistance training can significantly slow down muscle loss and even help build new muscle, contributing to a longer, healthier life. A minimum of two sessions of resistance training per week is recommended to help counteract muscle loss after the age of 30.
Conclusion
In a world where carbohydrates often take centre stage, it’s time to reconsider the starring role of protein in our diets. By prioritising protein intake and engaging in regular resistance training, we can preserve muscle mass, boost metabolism, and support healthier ageing. It’s not just about adding years to your life but adding life to your years. So, next time you plan a meal, think of protein as your ally in the pursuit of a longer, more active and healthier life.
If you’re looking to optimise your diet, maintain muscle mass, or simply improve your overall health through better nutrition, I can help. As a certified nutritionist, I specialise in creating personalised plans that align with your lifestyle and goals. Feel free to reach out for a consultation—together, we can build a sustainable path to healthier living! www.whitespacenutrition.com/services/
REFERENCES
1-Volpi, E., Nazemi, R., & Fujita, S. (2004). Muscle tissue changes with aging. Current opinion in clinical nutrition and metabolic care, 7(4), 405–410. https://doi.org/10.1097/01.mco.0000134362.76653.b2
2- Walston J. D. (2012). Sarcopenia in older adults. Current opinion in rheumatology, 24(6), 623–627. https://doi.org/10.1097/BOR.0b013e328358d59b
3- Carbone, J. W., McClung, J. P., & Pasiakos, S. M. (2019). Recent Advances in the Characterization of Skeletal Muscle and Whole-Body Protein Responses to Dietary Protein and Exercise during Negative Energy Balance. Advances in nutrition (Bethesda, Md.), 10(1), 70–79. https://doi.org/10.1093/advances/nmy087
4- Stokes, T., Hector, A. J., Morton, R. W., McGlory, C., & Phillips, S. M. (2018). Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients, 10(2), 180. https://doi.org/10.3390/nu10020180
5- Mamerow, M. M., Mettler, J. A., English, K. L., Casperson, S. L., Arentson-Lantz, E., Sheffield-Moore, M., Layman, D. K., & Paddon-Jones, D. (2014). Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. The Journal of nutrition, 144(6), 876–880. https://doi.org/10.3945/jn.113.185280 l
