Protein is made up of smaller units, amino acids, and is part of many of the different tissues in our body. It is also an important part of enzymes that carry out many of the integral reactions in our bodies. There are some amino acids that the body can synthesize, but others, essential amino acids, we have to get through our diet. Undernutrition of these amino acids could result in anemia, physical weakness, impaired focus, and weakened immunity.
In humans, the sources of dietary proteins essentially come from animals and plants. The amount and composition of these protein sources are different due to the mix of different amino acids. A healthy and balanced diet should include all amino acids and proteins from different sources and in different proportions.
In the case of how much protein each person should consume most of the research indicates that this is principally related to environmental factors and perhaps only varies 10-15 % due to genetic makeup. This would make recommendations for the amount of protein per day quite accurate for most of the population compared to other macronutrients. In general, in today’s society, we tend to consume a lot more protein than we metabolically need, and there is really no current evidence that this would increase performance or health except for certain states of disease or very high-level athletes.
Recently, different variations of low carbohydrate – high fat – high protein diets have become very popular in particular to achieve weight loss in the short term. Although we need to further study the health impact of this approach when applied long term, there are some negative outcomes associated with long term high levels of protein intake. These include:
– Increased overall mortality (all causes)
– Increased blood pressure and cardiovascular disease
– Increased incidence of type 2 diabetes
– Increased stress on kidneys
– Increased incidence of cancer
More research is required to understand long term effects of low carbohydrate – high fat – high protein diets, and it is important to remember that these diets can be useful in the short term. Our current understanding suggests that we should eat varied food long term and use such diets during short periods of time. It is also important to pay attention to the source of protein, in particular if you are using a high protein approach. Many of the possibly negative effects are directly associated with specific sources of protein, in particular red meat.