By
Melbourne Functional Medicine
Lorraine Cussen
Medically reviewed by:
It might surprise you to know that most people don’t eat enough protein, or they might not be absorbing it well. In this article we’ll cover what protein does in the body, why protein is important, how protein requirements change over life stages, what protein sources exist, and how to know if you’re getting enough.
Protein plays a crucial role in the body by serving as the building blocks for tissues, muscles, enzymes, and hormones. It's essential for growth, repair, and maintenance of cells. Proteins help in the development of muscle mass and strength, support immune function by forming antibodies, and facilitate biochemical reactions through enzymes. Additionally, proteins assist in transporting molecules throughout the body and maintaining proper fluid balance.
Without adequate protein, the body cannot repair damaged tissues, sustain muscle mass, or produce vital enzymes and hormones, leading to impaired bodily functions and overall health. Hence getting enough protein is required to keep your body running like a well oiled machine.
The consequence of not eating enough may result in low energy, low muscle mass, declining brain function, poor skin health, low immunity, high blood sugar, fatty liver disease, oedema (swelling in particularly in the abdomen, legs, feet and hands), thin brittle hair or hair loss, slow wound healing, and mood swings.
Overall, insufficient protein intake can significantly affect your health, physical performance, and quality of life.
Across the course of life, your protein requirements change depending on what stage of life you are in.
Infancy
It may be surprising to learn more protein is required per kg of body weight in our early years of life. Breast milk or infant formula should provide adequate protein for rapid growth and development. The recommended daily intake (RDI) up to 6 months of age is 1.12g/kg/day.
Childhood
Even though protein is required to support muscle and tissue development during this stage, by 10 years of age the required amount (RDI) is reduced to 0.74g/kg/day.
Adolescence
When growth spurts occur, higher protein intake may be necessary to meet increased demands. This can be challenging when teenagers are changing their eating habits away from the family routines, choosing more ultra-processed foods (chips, lollies, biscuits), fast foods, large amounts of carbohydrates (pizza, chips, hamburgers) or restricting their diets to appease social mores and peers.
Having plenty of pre-cooked protein or quick and easy protein snacks on hand around the house, as well getting teenagers involved in food prep can be a helpful strategy to avoid the ‘junk food’ and carbohydrate overload.
Adulthood
Protein needs typically stabilise during adulthood, but remain important for maintaining muscle mass, supporting immune function, and overall health. The RDI for adults still currently recommends 0.8g/kg/day, although most people require more than that, from upwards of 1g/kg/day.
That said, daily protein intake should be individualised based on your own needs. For example, if you’re exercising five days a week (cardio and weight training), you may find the RDI of 0.8g/kg is insufficient to maintain good energy and muscle mass. For those wishing to build muscle, recommendations for protein intake range from 1.6g/kg/day to 2.2g/kg/day. Those who are convalescing or recovering from surgery may also need more protein to help the body heal. In these cases, often increasing protein intake to 1.5g/kg of body weight is suggested. So if you weigh 63 kg, your requirements would be 94.5g of protein daily. You could divide this up into 30g of protein per meal and use the table further down this page to calculate some foods you may be eating.
Pregnancy and breastfeeding
During this phase, the body’s protein requirement significantly increases to support the growth and development of the foetus or infant. The general recommendation is to increase protein by about 20g/day compared to non-pregnant women.
Older adults
If you're an older adult, your protein needs may slightly increase to help counteract age-related muscle loss and maintain strength and function. As protein digestion tends to become compromised in later years, digestive support may be helpful for some people.
So when considering protein intake, consider not only your life stage, but your level of activity, lifestyle, state of health and whether digestion might be needing support. A functional medicine practitioner can determine an ideal protein goal for you depending on your health, age, and goals.
Protein foods include animal products like meat, fish, poultry, eggs, plus plant based proteins - pea, tofu, tempeh, legumes, beans, nuts and seeds. Protein powders can also be supportive in meeting daily requirements, mixed together in smoothies or added to meals.
Below is an indication of what 30g of protein looks like based on common protein sources.
A good way to see if you’re getting enough protein is to track your food intake over a few days, or ideally, a week. Use a tracking app like Chronometer to record your intake and check you're meeting your RDI, being mindful that the RDI may not be adequate based on your needs.
It's important to eat protein with every food choice, whether main meal or snack. Protein keeps your blood sugar balanced and creates satiety (a feeling of fullness).
The consequence of not eating enough protein can be blood sugar spikes, lower energy, declining muscle mass, cognitive impairment, poor skin health, lowered immunity and more.
There is a downside to increasing your protein intake, as too much can also cause problems.
Excess protein cannot be stored and can be converted to fat, although it is not a major contributor to fat gain, particularly in comparison to fats and carbohydrates. It can also create acidity in the body if not balanced with plenty of fruits and vegetables.
The key to optimal health is to balance your protein intake with the correct amount of carbohydrates and essential fatty acids, and to make sure your protein intake is in the sweet spot - not too little, not too much.
Digestive health issues such as low stomach acid, small intestinal bacterial overgrowth (SIBO), pancreatic insufficiency, liver disease, gallbladder disease and chronic stress can all affect our body’s ability to break down and absorb protein efficiently.
Treating, supporting and correcting digestive health with your practitioner will ultimately improve your body's ability to digest and absorb the important nutritional value of protein.
Protein adequacy or sufficiency should be considered on a person to person basis. Factors to consider are your stage of life, physical activity, health status (well or convalescing), your goals (weight loss, muscle gain) and your gender or age.
Working with a functional medicine practitioner is a step forward in determining your individual protein requirements. Testing and supplementing should only be completed under the guidance of a qualified practitioner.
