Protein is the building block of life, but how much do we really need? where can we find it? and which sources are best?
What is Protein?
Protein is a nutrient - and one that is essential for the human body. Proteins are one of the building blocks of our body tissue and can also serve as a fuel source.
Protein molecules are made up of amino acids, these all come from plants. Both human and non human animals require protein but as we cannot make amino acids ourselves, we need to get them from our food.
There are nine amino acids that are essential for humans that are obtained from what we eat. Plants such as soy and quinoa contain all nine, most other plants do not - however, eating a mixture of plants provides all the essential amino acids needed.
How much Protein do we really need?
Today, people are more likely to suffer from conditions relating to excess consumption of protein than of protein deficiency, and yet we seem to keep seeking more. Interestingly, protein is marketed as the key to both weight loss and weight gain, something that obviously cannot be the case. So the facts are little muddled, but just how much do we really need?
The Australian Recommended Dietary Intake (RDI) is 0.75 grams per kilogram of body weight for women, or 0.84 grams per kilogram of body weight for men. The United Nations World Health Organisation more conservatively recommends 0.66 grams of protein per kilogram of lean body mass.
Despite this, the most popular formula floating around today is 1 gram of protein per kilogram of body weight. 1 gram per kilo might be appropriate for endurance athletes, babies or the elderly, all of whom have slightly higher requirements than the general population. Using 1 gram as the target, and also using body weight instead of lean body mass, has left us all believing we need far more protein than we actually do.
Want to find out how much protein you need? Try this calculator
Where can we find Protein?
We've been lead to believe that protein = meat, perhaps surprisingly to some people, protein is found in most foods, even potatoes! Contrary to popular belief, it is not necessary to eat animal products to get the protein you need.
Plants offer us an abundant source of protein, it isn't difficult to achieve your protein requirements by eating only plants.
Of course some foods are higher in protein than others, but remembering that our actual requirement for protein might not be as high as we thought, if we are eating enough calories then by default we should be eating enough protein - without even trying.
Plant vs Animal Protein sources - does it matter?
If there is protein in both plant and animal foods, does it matter which source we choose? Putting aside the obvious ethical element to that question, the answer is Yes! Why? because animal proteins effect our body differently to plant proteins.
Plant proteins come packed antioxidants and benefits not found in animal proteins such as:
Phytochemicals, the bioactive non-nutrient plant compounds in fruit, vegetables, grains, and other plant foods, these have been linked to reductions in the risk of major chronic diseases; and
Fibre, the indigestible parts of plant foods, such as vegetables, fruits, grains, beans and legumes. It is type of a carbohydrate that helps keep our digestive systems healthy
All of the healthful components we need originate in plants, not animals. If they are present in the animal product, it is because the animal ate plants, or ate an animal that ate plants.
What plant-foods don't have, we can do without. Many people do not realise that only animal products contain cholesterol. Both human and non-human animals make their own cholesterol, we have no requirement to consume it in our food. Plant proteins are completely free from cholesterol, and most are free from or low in saturated fat.
Diets high in animal protein can lead to adverse health effects including disorders of the liver and worsening of coronary artery disease. Michael Greger MD of nutritionfacts.org says "animal protein consumption also appears to trigger the release of Insulin-like growth factor 1, a cancer promoting growth hormone".
Plant protein sources do not have these harmful effects.