Protein is one of the essential macronutrients that our body needs to function properly. It helps build and repair muscles, bones, skin, hair, and other tissues. It also supports our immune system, hormones, enzymes, and neurotransmitters. But how much protein do we need per day? And does it change depending on your age and stage of life?
The answer is yes, it does. Just as our body changes throughout our lifespan, so do our protein needs.
Protein needs by age group
According to the Dietary Reference Intakes (DRIs) published by the US National Academy of medicine (NAM), the Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight per day for adults. This means that an average adult who weighs 70 kg needs about 56 grams of protein per day. However, this is a general guideline and some factors that may affect your protein needs include your activity level, health status, and body composition.
For example, older adults may need more protein than younger adults to prevent muscle loss and sarcopenia, a condition of reduced muscle mass, strength, and function. A review of studies suggests that older adults may benefit from consuming 1 to 1.2 grams of protein per kilogram of body weight per day, or even up to 1.5 grams for those who are weak or have chronic diseases.
Similarly, pregnant and breastfeeding women may need more protein than non-pregnant women to support the growth and development of their baby and their own increased metabolism. The RDA for protein during pregnancy is 1.1 grams per kilogram of body weight per day in the second and third trimesters, and 1.3 grams during lactation.
Children and adolescents also have higher protein needs than adults to support their growth and development. The RDA of protein for children and adolescents varies by age group as follows:
- 1 to 3 years: 1.05 grams per kg of body weight per day
- 4 to 8 years: 0.95 grams per kg of body weight per day
- 9 to 13 years: 0.85 grams per kg of body weight per day
- 14 to 18 years: 0.85 grams for girls and 0.8 grams for boys per kg of body weight per day.
Why is protein important?
Protein is important for many reasons, but especially for maintaining muscle mass and strength throughout your life. Muscle mass is not only important for physical performance and mobility, but also for metabolic health and longevity. Muscle mass helps to regulate blood sugar levels, insulin sensitivity, inflammation, and energy expenditure.
However, as we age, we tend to lose muscle mass due to various factors such as hormonal changes, reduced physical activity, chronic diseases, and inadequate nutrition. This can lead to loss of muscle, which increases the risk of falls, fractures, disability, and mortality.
One way to prevent or slow down muscle loss is to consume enough protein every day, especially high-quality protein that contains all nine essential amino acids that our body cannot make on its own. Essential amino acids are especially important for stimulating muscle protein synthesis (MPS), the process of building new muscle tissue.
Another way to preserve muscle mass is to engage in regular resistance training or strength exercises that challenge your muscles against some form of resistance such as weights, bands, or your own body weight. Resistance training not only increases MPS but also improves muscle function and quality.
How to increase protein intake on a plant-based diet
If you follow a plant-based diet or want to reduce your intake of animal products, you may wonder how to get enough protein from plant sources. The good news is that there are many plant-based foods that are rich in protein and can help you meet your daily needs.
Some examples of plant-based protein sources are:
- Legumes such as beans, lentils, chickpeas, peas, soybeans, tofu, tempeh, edamame
- Nuts such as almonds, walnuts, pistachios, cashews
- Seeds such as chia seeds, flax seeds, hemp seeds
- Grains such as quinoa and oats
- Nutritional yeast
- Spirulina
- Seitan.
However, not all plant proteins are complete proteins that contain all nine essential amino acids in adequate amounts. Most plant proteins are low in one or more essential amino acids such as lysine or methionine. This means that you need to consume a variety of plant proteins throughout the day to ensure that you get all the essential amino acids that your body needs.
One way to do this is to combine different plant proteins that complement each other in terms of their amino acid profile. For example, you can pair legumes with grains, nuts, or seeds to create a complete protein meal or snack. Some examples of plant protein combinations are:
- Hummus with whole wheat pita bread
- Bean and rice burrito
- Lentil and quinoa salad
- Peanut butter and oatmeal
- Almond butter and banana toast
- Chia seed pudding with almond milk.
Another way to increase your protein intake on a plant-based diet is to use protein powders or supplements that are derived from plant sources such as pea, rice, hemp, or soy. Protein powders can be added to smoothies, shakes, oatmeal, or baked goods to boost your protein intake and provide essential amino acids. However, protein powders should not replace whole foods as your main source of protein, but rather complement them.
To meet our protein needs, we should consume a variety of high-quality protein sources every day. If you follow a plant-based diet or want to reduce your intake of animal products, make sure to consume enough plant proteins that provide all the essential amino acids that our body cannot make on its own.
Information sources
Abbott nutrition. (2019). Science-backed Nutrition for Every Stage of Life. https://www.nutritionnews.abbott/healthy-living/diet-wellness/science-backed-nutrition-for-every-stage-of-life/
European Food Information Council (EUFIC). (2022). Plant-based protein: all you need to know to get enough of it
Messina, M., Duncan, A. M., Glenn, A. J., & Mariotti, F. (2023). Perspective: Plant-Based Meat Alternatives Can Help Facilitate and Maintain a Lower Animal to Plant Protein Intake Ratio. Advances in Nutrition
Nichele, S., Phillips, S. M., & Boaventura, B. C. B. (2022). Plant-based food patterns to stimulate muscle protein synthesis and support muscle mass in humans: a narrative review. In Applied Physiology, Nutrition and Metabolism (Vol. 47, Issue 7, pp. 700–710). https://doi.org/10.1139/apnm-2021-0806
Villines, Z. (2018). 15 best plant-based protein foods. Medical News Today. https://www.medicalnewstoday.com/articles/321474