The structure of protein
Protein is made from chains of molecules called amino acids held together with peptide bonds.
Long chains of amino acids are classed as proteins.
Essential amino acids. These are amino acids that we need to take in our diet. Our bodies cannot make them from the basic building blocks of molecules.
Why do we need protein?
We need the building blocks of protein (amino acids) to make muscle, bone, tissue and skin. And we also need amino acids to make enzymes, hormones and even our DNA. In fact 16% of our body is made up of protein. We cannot make protein from carbs or fat and we don’t store a lot of protein. So we must constantly replace protein by eating it in our diet.
If we do not have enough protein in our diet we start to break down muscle to obtain it. A diet chronically low in protein will prevent you from being able to build up muscle and therefore build strength. Exercise will become harder and you will feel weak and tired (similar to over-training).
Enzymes and hormones may be in short supply due to lack of the right amino acid building blocks. As we get older we lose muscle bulk, so it’s important to keep up an adequate protein intake and do exercise to keep the muscles strong and healthy. There is some evidence that poor protein intake is related to osteoporosis.
So we must eat protein in the form of meat, fish, eggs, cheese or vegetable sources, break it down into amino acids then build it back up into the right kind of protein that we can use.
How much protein do we need?
Many humans these days do not get enough protein in their diet and get too many calories from sugar and carbohydrate. Many obese people appear to be protein deficient with central obesity. On the other end of the scale we also have people eating too much meat and animal protein, especially if trying to put on muscle.
Sources of protein
Animal protein – meat both red and white, fish, cheese, dairy and eggs.
Vegetarian sources of protein are legumes, nuts, seeds, grains, tofu and soy as well as pea protein, hemp, and spirulina.
How much protein should we eat per day?
Nutritionists recommend 1g of protein per kg of body weight. However requirements will increase in people who exercise a lot. Meat, chicken, fish and cheese have around 25g of protein per 100g. The amount of protein varies quite a bit depending on what cut and type of meat and whether it’s raw or cooked, so don’t be surprised if you see several different values online. In other words, ¼ of the meat we eat is protein; the rest is water, fat and other compounds. Eggs have 12g protein per 100g, or 1 large whole egg will have 6g of protein. Nuts, seeds and legumes have around 20g of protein per 100g, while beans have a bit less at 10g protein. Fruit and vegetables have only small amounts of protein except for peas.
So the average person needs between 70g to 150g of protein per day, then they will need only 600g maximum of meat per day. Many people eat much more than that. The best way to get protein is to get it from a variety of healthy sources such as meat, fish, cheese, eggs and vegetarian sources such as beans, legumes, nuts and seeds.
Below is a printable table showing the average protein content of various foods:
Protein input and exercise
A good general recommendation is:
- Sedentary adults: 1g/kg body weight
- Moderately active adults (up to 3 training sessions per week): 1-1.5 g/kg bodyweight
- Very active adults (3 or more training sessions per week): 2g/kg bodyweight
As there are no hard and fast rules, individual athlete’s protein requirements may vary. Trial with different amounts may be the best bet.
Quality of food
What’s most important is the quality of the food source. Our food has been so altered by intensive farming methods that foods that were quite acceptable sources of good protein in the past have been changed to contain more harmful chemicals and fewer nutrients than ever before. Much research has been done on the harmful effects of red meat on the incidence of heart disease and cancers. No-one however has looked at whether it’s the quality of the meat that’s causing the problem.
When you think about it, cows have evolved from wild buffalo that roamed over vast areas, eating nothing but grass. Now they stand idle in fields (if they are lucky enough to be outside), are fed grain and fish meal (not their natural foods), and then injected with growth hormone and antibiotics to increase their weight. They are high in fat – much like us – and the meat sits deteriorating in supermarkets for long periods wrapped in plastic before we eat it.
Now all mammals store toxins in their fat, in much the same way that computer software quarantines viruses from harming your computer. When we eat animal fat, we are eating the toxins that the animal has been exposed to – pesticide and fertiliser residue, hormones and anti-biotics. No wonder it’s bad for us.
Why do they need antibiotics and growth hormone?
Meat and animals are sold by weight. Therefore, farmers want their animals to gain weight so that they get a better price per animal. Anything that improves weight, like growth hormones or food that encourages weight gain, will improve the profitability of the herd. The farmers don’t necessarily care what it does to the meat from those animals- they have to make a living.
Furthermore, animals that are kept together in close quarters often get infections. Antibiotics get rid of the infections, prevent future infections and also improve weight gain. So most farmers are keen to use them.
When it comes to poultry, it’s appalling the way chickens are being reared nowadays. They are kept in overcrowded conditions in large barns, never seeing the outdoors or being able to run around. They have only one source of food – grain – and are fed hormones and antibiotics again.
In the past chickens had a varied diet of insects and other small creatures as well as grain, and ran around the yard all day exercising. Now they are bred to develop large breasts for white meat and can barely stand up. No wonder they are becoming higher in unhealthy fat and their meat is lacking in nutrients.
What to Do
If you are eating meat, try to eat lean sources of good quality meat, and cut fat off before cooking. Remember that any toxins that the animal has absorbed such as pesticides etc will be stored in the fat. A small amount of good quality meat is much better than a larger amount of cheap meat like mince or ground beef which will often have pink slime added as a filler. This is made from trimmings off the cow, like cartilage and connective tissue and is often injected with ammonia to kill bacteria – not the healthiest of products. Ground beef can have up to 15 or 25% pink slime added depending on which country you live in. Sausages often contain similar pink slime and other fillers such as soy, rice or grain. Get your sausage from a local organic butcher and ask what filler they use.
Buy free range, organic meat rather than supermarket meat. Source local organic farmers in your area, and get together with friends or family to buy in bulk to reduce costs. Buy a whole piece of beef and make your own ground beef for hamburger patties. That way you know exactly what went into it. I see many clients who only eat chicken and they often have a low zinc and iron. So I recommend small amounts of healthy organic red meat such as lamb or wild sources like venison, kangaroo or ostrich. These meats, because they exercise a lot running wild or on farms, have higher levels of Omega 3 than intensively reared animals such as chickens and have a more natural diet in the wild.