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All about protein

by | Nov 16, 2023 | Uncategorised

Top down view of six small bowls, sitting on a grey stone surface, each filled with a different type of nuts

Everything you need to know about protein and your diet

Most people know that they need to eat protein, but do you know how much and why and what foods are the best protein source?

All about protein.

Protein is a macronutrient and is essential for building and repairing tissues in the body.

Protein is made up of a bunch of amino acids, which are the basic building blocks of protein. There are 20 amino acids that are needed by the body. The body is clever and can create 11 of these, but 9 are considered ‘essential.’ These 9 cannot be synthesised inside the body and must come from your diet instead.

In case you are interested, the 9 essential amino acids are:

and valine

Complete and Incomplete proteins, what is the fuss about?

You may have heard about complete and incomplete protein sources.

A complete protein source is one that contains all 9 essential amino acids, whilst an incomplete protein source may contain only some of the 9.

Examples of complete protein sources are animal meat and soybean products eg tofu, soybeans, tempeh.

It is important to note that when looking at your protein source, you should also consider other macronutrients that may not be so beneficial. For example, focusing on eating steak every day will give you a wonderful protein source but will also be full of saturated fat which has a negative effect on your health if eaten in excess.

Consider moderating your intake of the fatty cuts of meat and look instead for the leaner meat cuts and plant-based sources of protein. This will give you the protein benefits but without the saturated fat content.

Now I mentioned that only animal and soybean products contain all essential amino acids and are considered complete. You may hear that incomplete plant protein sources are therefore not good enough as they don’t give you everything you need. This would be true if you only ate one plant-based protein source. However, in reality, people vary their diet. So, as long as you get a varied protein source over your day and your week then you will get all essential amino acids needed. It is nearly impossible to become deficient in any one essential amino acid.

Why do we need protein in our diet?

 When we eat protein, the stomach’s hydrochloric acid breaks down that protein back into its amino acids. These get absorbed into the body and they are built into the proteins that the body needs.

Below is a list of reasons the body needs protein:

  1. Repair and maintenance of tissues: Protein repairs all muscles, bones, skin and organs. Pretty important right!
  1. Structural support: protein gets built into the cell structure to provide support for cells, tissues and organs. These include collagen, keratin and elastin.

Collagen is the most common protein found in the body and is essential in keeping your skin, ligaments and tendons healthy.

Elastin stretches more than collagen and provides the stretchiness that is needed in organs that change shape eg lungs, blood vessels and uterus. It helps blood flow well around your body and also gives your skin its youthful appearance and stretchiness.

Keratin is needed for strong hair, nails and skin.

  1. Enzymes and hormones: Proteins act as enzymes which allow chemical reactions in the body to function well. Proteins also act as hormones which are messengers that regulate your bodily functions.
  1. Fluid and pH balance: Protein is essential in maintaining fluid and acid-base balance within the body. Without enough protein, fluid is more likely to seep out of blood vessels and you find you retain fluid.
  1. Immune function: Protein supports a strong immune system. It helps produce antibodies that help fight off infections. Want to fight off your next cold? One way is to eat enough protein each day!
  1. Energy source – Protein can be used as an energy source if fat and carbs (glycogen) is not available.
  1. Nutrient transporter and storage– Proteins transport vitamins and minerals around the body, bringing them to wherever they are needed. They can also store nutrients, for example ferritin is a protein that stores iron.

How does protein benefit how I actually feel?

Now we know what protein does inside of the body, the main thing is how that equates to how you actually feel.

Eating enough protein has so many benefits to your day to day and long-term health. Here’s a lovely list to make it easy to digest:

  1. Feeling full for longer. Protein switches off your hunger hormones and switches on your satiety hormones for much longer than eg simple carbohydrates like bread or pasta. This means you stay full for longer, not needing to reach for unhealthy snacks or overeat a few hours later.
  2.  Increased energy levels. Protein is digested much slower than other foods like carbohydrates, this means you get sustained energy levels and fewer energy dips in your day. (Goodbye to that mid-afternoon energy slump!!)
  3. Increased muscle mass. This is a very important factor in why you must eat lots of protein each day through midlife and beyond. After the age of 35, you lose muscle mass with each year of your life. This may not matter when you are 40 or 50, but eventually this will catch up with you. Mobility issues, pain, unable to do your regular activities like walking to the shops or holding shopping bags. Muscle is really an important part of healthy aging. We must support our muscles with adequate protein intake otherwise you will lose your independence much quicker!!
  4. Better blood sugar control. This is most important for diabetics but can be so important to pre-diabetics and non-diabetics wanting to keep their blood glucose in check and their insulin as sensitive to glucose as possible.
  5. Better blood pressure control.
  6. Improved ability to fight off infections. Remember, proteins help produce antibodies that fight off infections. Eat protein to boost your immune system.
  7. Weight management. Because protein fills you up for longer, it can be a way of reducing your overall calorie intake without really trying as you won’t be as hungry in between meals. This may aid weight loss. 

How much protein do I need to eat each day?

The recommended daily allowance (RDA) for protein is 0.75 to 0.83g of protein per Kg of body weight per day.

Recommendations by individual countries varies only slightly:

  1. The United States: The US Recommended Dietary Allowance (RDA) for protein is 0.8 g/kg for healthy, sedentary adults.
  2. The United Kingdom: The Reference Nutrient Intake (RNI) for protein is 0.75 g/kg
  3. Australia and New Zealand: The Nutrient Reference Values (NRVs) for protein are 0.84 g/kg for adult men and 0.75 g/kg for adult women
  4. Canada: The Recommended Nutrient Intake (RNI) for protein is 0.8 g/kg for healthy adults
  5. European Union: The European Food Safety Authority (EFSA) recommends a protein intake of 0.83 g/kg for adults
  6. World Health Organization (WHO): The WHO recommends a protein intake of 0.83 g/kg for adults

Over the age of 65yrs and healthy, the daily protein requirement increases to 1.0-1.2 g protein/kg, according to the International PROT-AGE Study Group and European Society for Clinical Nutrition and Metabolism (ESPEN.)

There is considerable evidence that if you are in midlife, you should be aiming more for the over 65 year old requirement, especially if you are incorporating exercise into your life. 

In mid-life, I would aim for a minimum of 0.8g of protein/kg but try to get 1.0g -1.2g of protein/Kg each day.

An example: 

A 55 yr, 70kg woman would need between 70g and 84g of protein per day.

A 60 yr, 90Kg man would need between 90g and 108g of protein per day.

Then once you are over 65yrs old, your protein requirement goes up more as your muscle loss speed increases.

This is according to the International PROT-AGE Study Group and European Society for Clinical Nutrition and Metabolism (ESPEN.)

It is important to remember, this is a general requirement and is not specific to you and your activity levels. But as a good ballpoint, it can be incredibly useful to know roughly what your requirements are.

Roughly, a midlife man or woman should aim to eat 20-30g of protein with each meal. If you want a snack, consider 10-15g of protein per snack.

Let’s put that in an example.

A 55 year old 70kg woman who eats 20g of protein for breakfast, lunch and dinner and has a snack containing 10g of protein, will eat 70g of protein in that day. This is the equivalent of 1g/kg which is perfect for her.

Where to get my protein from?

Now we know how much protein you should be getting each day, what does that mean for you when you choose your meals.

There are many sources of protein, including:

  • Meat,
  • Fish and seafood
  • Dairy – milk, cheese, yogurt etc.
  • Legumes – beans, lentils, chickpeas etc.
  • Nuts and seeds

Remember to try to get most of your protein from plants and lean sources of animal protein, to avoid high levels of saturated fat in your diet.

Here is a list of protein sources and their protein amount per 100g.


Here is a table of the top 20 protein sources, including their name and protein content per 100g, based on the search results:


Protein Source Protein content per 100g



Dry-roasted soybeans


Grated parmesan cheese


Lean veal top round


Lamb shoulder roast


Lean chicken breast


Non-fat mozzarella


Lean pork chops


Tuna steak




Beef jerky










Firm tofu


Silken Tofu 









| Black beans | 21g[5] |

Lean steak 20-25g per 100g

Pumpkin seeds


Chia seeds




Sesame seeds


Sunflower seeds 20.8g


Milk, skimmed or 1%: 3.38g

Low-fat yogurt: 5.25g

Eggs: 12.4g (1 large egg contains 7.5g of protein)

Oats: 16.89g


Protein is absolutely essential for anyone in midlife wanting to look after their health and keep their independence for longer into older age. You will build and maintain muscle mass, help with weight management and improve your immune function and metabolism.

Remember, the RDA of protein may not be enough for you in midlife due to faster rate of loss of muscle mass as you get older.

So, whilst the RDA for all adults up to the age of 65yrs old is roughly 0.8g of protein/Kg, I would ask you to aim for 1g-1.2g of protein per Kg body weight per day to keep you on track for better muscle mass and independence into older age.

And if you are over 65, definitely aim for 1g-1.2g of protein per Kg per day.

Day to day, choose the protein sources that bring the most other nutrients and the least amount of saturated fat. Examples would be plant sources like nuts, seeds, beans and other legumes and lean animal proteins like chicken breast and fish.


If you don’t get much protein each day, then going up to this amount is probably daunting.

So, let’s consider a realistic goal to set out and achieve.

You must think about what you like to eat as otherwise you will not achieve the goal.

A SMART goal means – Specific, measurable, attainable, relevant to your needs and time restricted.

Start with one goal and stick with it for a time period eg 30 days. By doing that, you will then find it easier to make further changes.

An example:

I will eat 30g (2 tablespoons) of ground flaxseeds on a 50g bowl of porridge with 150mls of skimmed milk or plant milk, with a small handful of almonds every day for the next 30 days. (25.1g of protein)

Let me know how you get on the comments below!


Written by thelifestylehealthdoctor

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