Protein in Your Diet
We eat every day, our diet comprises of complex foods which contain mixtures of carbohydrates, fats and proteins.
Protein is one of the most important nutrients, helping build muscle, skin, enzymes and hormones, so unsurprisingly a protein deficiency can have a big impact on body function. There are seven symptoms to look out for that could indicate that you need to increase your protein intake.
Protein is an essential part of the human diet for growth and repair of the body. All cells and tissues contain protein especially muscle tissue. Structural components of the body rely on a continual supply of protein. Protein from animal sources (e.g. poultry, fish, and eggs) contains the full range of protein. However, vegans and vegetarians can get all the protein they need by combining different plant sources of protein, e.g. pulses, tofu, nuts, seeds and vegetables.
What is protein?
Proteins are fundamental structural and functional elements within every cell of the body and are involved in a wide range of metabolic interactions. Proteins are the key structural compound that make human tissue. It is made up of various combinations of small organic chemicals called amino acids. Different foods contain different amounts/combinations of amino acids.
Proteins are complete long chains of smaller amino acid molecules joined in a peptide bond. These long chains are folded into particular shapes. The long chains of amino acids fold to give each type of protein molecule a specific shape. Our bodies are able to put these basic amino acid units together, using different arrangements of amino acids, to produce specific fibrous proteins, which can only be produced if all the necessary amino acids are available.
Where do you find protein?
The nutritional value of a protein food can be judged by its ability to provide both the quantity and number of essential amino acids needed by the body. Different food sources contain different groups of proteins, which are made up of different arrangements and amounts of amino acids.
When we eat food containing protein it is broken down during digestion into its constituent amino acids. These amino acids are absorbed by our bodies and are used to produce new proteins and other necessary substances. Our bodies can make some of the amino acids needed to manufacture proteins, but others must be obtained from the diet; these are the eight so-called ‘essential’ amino acids. In addition, one other amino acid is needed by infants during early growth and development.
Cooking can alter the amino-acid composition of protein and this usually results in desirable flavour and browning development. Very little nutritional value is lost.
Chicken breast (grilled without skin)
Fish Tuna (canned in brine)
Low fat yogurt (plain)
Pulses Red lentils
Beans Kidney beans
Tofu (soya bean steamed)
Grains Wheat flour (brown)
Rice (easy cook boiled)
Pasta (fresh cooked)
How much should I consume?
Adults and children should consume two to three servings of protein every day. If plant sources dominate, it is important to make sure that different types are consumed.
One typical portion size equates to:
• 100g of lean boneless meat (red and poultry)
• 140g of fish
• 2 medium eggs
• 3 tablespoons of seeds or nuts.
It is important to choose lower fat protein-rich foods, such as lean meats or reduced fat dairy products as some high protein foods can also be high in saturated fat. This will help minimise the risk of developing cardiovascular disease.
RECOMMENDED DAILY DIETARY INTAKE OF PROTEIN
The recommended dietary intake (RDI) of protein 1g per 1kg of body weight per day. The protein intake for a 68-kilogram man is 68 grams and for a 50-kilogram woman, 50 grams per day.
A lack of protein in the diet can lead to muscle wasting away.
Higher levels of protein intake appear not beneficial or harmful. If your calorie intake is low that day, your cells can convert excess amino acids to molecules that can burn as fuel.
On the other hand, if you consume plenty of calories, your body has no choice but to convert the extra protein to fatty acids and store them under your skin.
However, it is possible that extra calcium may be required to counterbalance an excessive protein intake. Also there is a load of protein breakdown products, which must be sorted out by the kidneys.
Protein and weight management
A lean protein meal can help to minimise feelings of hunger and decrease overall energy intake. Protein-dense foods give the eater a fuller feeling than foods plentiful in carbohydrates or fat. A high protein diet has been shown to produce fat loss results.
Some studies have shown a protein-enriched diet with a low carbohydrate content to be associated with slightly greater initial fat loss compared with widely recommended low fat eating programmes. However, no differences have generally been reported when comparisons have been made over a longer duration (e.g. after 12 months).
Long-term studies are needed to compare the effects of protein-rich, low carbohydrate diets versus low fat diets on nutritional status and body composition and to assess their effects on disease risk and nutritional status.
Some popular high protein, low carbohydrate diets claim to be effective at despite a high fat intake from fatty meats and full fat dairy products.
Such a diet remains contradictory to current healthy eating messages.
Regardless of the composition of the diet, weight loss will only occur if a deficit in energy intake compared to output through activity is created to achieve a negative energy balance.
There are concerns about very-high-protein diets that involved cutting out other food groups and therefore caution be exercised in promoting these.
In conclusion, reducing energy intake in order to lose weight, reduce intake of some excessively fatty foods but maintain intake of low-fat, protein rich foods.
In the context of a lower energy intake, this will result in a relatively high proportion of energy coming from protein in the diet, but will not represent an increase in the total amount of protein consumed or require carbs to be completely cut out of the diet.