How much protein do I need?
Tracking and supplementing protein intake is not just for body builders.
Recent research has indicated that many of us may not be consuming enough protein.
Whilst the general dietary guideline for sedentary people is a daily protein intake of 0.8 g per kg of bodyweight, factors, like age, gender and activity levels can push that requirement way higher.
Read on to find out
why protein is important?
how much protein you need?
what protein sources are best?
when and how to consume it?
What is protein used for in the body?
Protein is a vital macronutrient. The sub-units of protein are amino acids – and these are used to build a huge variety of different proteins with important functions across the body.
Our bodies can synthesis some amino acids, but there are nine ‘essential’ amino acids our bodies need and can only be acquired though our food.
We probably all know that protein is used to build and repair muscle, but amino acids are also the primary building blocks for skin, tendons, ligaments, and bones.
Amino acids are also important for keeping the immune system healthy and for the synthesis of hormones and enzymes.
Proteins also important for balancing the fluid in your body. Albumin and globulin are proteins in your blood that help maintain your body’s fluid balance by attracting and retaining water.
Protein also plays a vital role in regulating the pH in your blood and other bodily fluids.
Yep, it’s important stuff!
Who needs extra protein?
Many groups need more protein.
1. Men
Men’s bodies tend to have a high proportion of muscle and hence they have higher protein needs than women.
2. Athletes… and anyone doing exercise
Athletes need extra protein. Exercise causes wear and tear on our muscles that needs to be repaired. If done optimally this results in muscle growth (atrophy) and increases in strength and endurance.
Indeed, since all of us should be enjoying 150 minutes of exercise a week for good health, we all likely need more protein than the basic 0.8 g/kg of body weight recommended for sedentary individuals.
The Australian Institute of Sport recommends of a protein intake of for athletes of 1.2-1.6 g/kg body weight daily.
Body builders may increase this to 2.2 to 2.6 g g/kg of lean body weight per day.
3. Children, adolescents and when pregnant of breastfeeding
If you are building a body, you are obviously going to need more protein for all its structural and functional properties.
Children ages 4 to 9 need 19 grams of protein each day. Those between ages 9 and 13 need 34 grams.
For adolescents, ages 14 to 18, it varies by gender: Boys need 52 grams and girls need 46 grams.
The amounts will need to be increased for active kids.
If you are pregnant or breastfeeding you need around 71g of protein per day compared to 46g for the average sedentary young woman
4. People who are sick, recovering from surgery or malnourished
The same logic applies if you are repairing a body, you are going to need extra protein.
5. Older people
We all gradually begin losing muscle mass and strength sometime in our 30s or 40s. This process picks up between the ages of 65 and 80. It leaves older individuals vulnerable to frailty.
You can counter sarcopenia by doing resistance training and increasing your protein intake.
In 2013, an international group of experts in the PROT-AGE Study Group increased the recommended protein intake for healthy over 65’s to 1.0–1.2 g protein/kg of body weight – more if unwell.
And an increased dietary protein intake may also be required earlier in life in order to mitigate the muscle ageing process.
A recent study following healthy participants aged between 55 and 77 years eating the previously recommended 0.8g of protein kg of body weight found that their mid-thigh muscle area decreased over the course of the 14 week study.
Personally, as an active woman in my early 50s, I’m aiming for a daily protein intake around 1.6g/kg of body weight to build and maintain my muscles.
6. People losing weight
Muscle mass loss is also common during weight loss – especially rapid weight loss. Again, you can counter this by upping your protein intake and doing resistance training.
Athletes trying to lose weight but retain muscle mass are advised to consume 1.6-2.4 g/kg body mass daily.
And patients taking GLP-1 agonist weight-loss medications are advised to up daily protein intake to 1-1.5 g/kg of body weight.
Can you have too much protein?
The breakdown product of protein – urea is excreted through the kidneys leading to the idea that too much protein in the diet might lead to kidney disease.
Reassuringly, recent studies have shown that high protein diets do not cause any kidney problems in healthy individuals. For example, one study followed young male body builders consuming 2.6 g/kg of body weight per day of protein for 8 weeks and 3.3 g/kg per day for 8 weeks (2.9 g/kg of body weight per day on average over the 16 week period). Even at this very high protein intake, there were no side effects (i.e., blood lipids, glucose, renal, or kidney function) related to the high protein consumption.
However, individuals with existing kidney problems will likely need to stick to a lower protein intake.
What are good protein sources?
Choose a mix of the following:
Try our regular Superflora shakes with a whey protein isolate (WPI)I base or our plant-based options with a mix of hemp protein, pea protein isolate and brown rice protein.
The WPI based shakes provide 25 to 27 g of protein per serve (depending on flavour), whilst the plant-based Superflora provide 17 to 18g per serve.
You can enjoy Superflora in a smoothie stirred through porridge or even in ice-cream. These recipes made with Rich Cocoa Chocolate Superflora have 36 g, 22.5 g and 6 g of protein per serve.
Your diet needs to contain all nine essential amino acids. Our shakes do that job.
All animal-based protein sources are also complete proteins.
Amongst plant-based options, soy and hemp seeds are also complete proteins. You can also combine plant-based food to make complete protein - by combining grains and legumes or adding nuts and seeds to legumes. There’s no need to have the combination at every meal, just eat a mixture across the day.
The amino acid leucine is particularly potent at driving muscle growth. Whey protein isolate is a great source of leucine and is very easily digested. And pea protein isolate is one of the best plant-based sources of leucine - Making our shakes excellent options for older and sporty individuals.
When should I eat my protein?
Spread your protein intake across all your meals and snacks rather than concentrating it in the evening meal. Every 3 to 4 hours is best.
You body can only absorb a limited amount of protein at each meal. Around 25 - 30g per meal is probably about right.
Body builders used to obsess about eating within 30 min to an hour or weight training, but it is now known that the anabolic window for building muscle mass is 24 hours, although assimilation is highest right after exercise and then drops off with time. A post workout shake is a great way to exploit this.
The importance of a balanced diet
Whilst we advocate for a diet with adequate levels of protein, that doesn’t mean we sit in the low carb, high protein camp.
A balanced diet with low GI complex carbs, healthy fats and high-quality protein is optimal for most people. If you have a specific health condition like diabetes, or kidney disease you’ll need to talk to your doctor or dietitian about your specific dietary needs.
Carbs are protein-sparing
Salad and chicken breast may appear to meet your protein targets but won’t give you enough fuel, especially if you are active. Carbohydrates are protein sparing, meaning they get used first to provide you with energy, leaving the protein for use in the body for physiological, maintenance and building functions, rather than fuel.
Go Mediterranean
Our favourite way to meet all the body’s needs is with the Mediterranean Diet, adapted to be low in FODMAPs if necessary.
You can read our blog on combining the low FODMAP and Mediterranean diets here.
And check out our many recipes here with a special list of plant-based, high protein options here.
We’d love to hear which are your favourites.
References:
Phillips, S. M., Chevalier, S., and Leidy, H. J. (2016) Protein “requirements” beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition, and Metabolism. 41(5): 565-572. https://doi.org/10.1139/apnm-2015-0550
Antonio et al. (2016) The effects of a high protein diet on indices of health and body composition – a crossover trial in resistance-trained men Journal of the International Society of Sports Nutrition. 13:3 DOI: 10.1186/s12970-016-0114-2
AIS Sports Supplement Framework Isolated Protein Supplements - Guidance downloaded from https://www.ais.gov.au/
Bauer, J., Biolo, G., Cederholm, T., Cesari, M., Cruz-Jentoft, A.J., Morley, J.E., Phillips, S., Sieber, C., Stehle, P., Teta, D., et al. (2013) Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from the PROT-AGE Study Group. J. Am. Med. Dir. Assoc. 14, 542–559. DOI: 10.1016/j.jamda.2013.05.021
Campbell, W. W., Trappe, T. A., Wolfe, R. R., Evans, W. J. (2001) The recommended dietary allowance for protein may not be adequate for older people to maintain skeletal muscle. J. Gerontol. A Biol. Sci. Med. Sci. 56, M373–M380. DOI: 10.1093/gerona/56.6.m373
Lonnie, M., Hooker, E., Brunstrom, J. M., Corfe, B. M., Green, M. A., Watson, A. W., Williams, E. A., Stevenson, E. J., Penson, S., & Johnstone, A. M. (2018). Protein for Life: Review of Optimal Protein Intake, Sustainable Dietary Sources and the Effect on Appetite in Ageing Adults. Nutrients, 10(3), 360. https://doi.org/10.3390/nu10030360
Blog written by: Noisy Guts co-founder Dr Mary Webberley. Mary has a background in biology, with two degrees from the University of Cambridge and post-doctoral research experience. She enjoys working out and challenging herself to gradually lift more kg.