Proteins are essential nutrients of energy and are made up of single units known as amino acids. Amino acids are the building blocks of the human body and are used to synthesise cells, muscle, organs, hormones and immune factors, as well as acting as buffers to regulate the acidity or basicity of the body.
Protein is important for the maintenance and health of our bodies, and the majority of Western populations consume adequate intakes for this. However, in developing countries the health problems associated with protein deficiencies are devastating, and it is the leading cause of death among children in these places. Carbohydrates have numerous biological functions in the body.
Aside from their important role in providing energy, they also have a structural role. Ribose, which is a component of coenzymes and the backbone of RNA, is a five C atom monosaccharide, and the closely related deoxyribose is a component of DNA. Carbohydrates also play key roles in the immune system and in blood clotting.
For athletes, the timing of fibre intake is important; high-fibre foods should be avoided in the hours leading up to a training session to avoid gastrointestinal discomfort. The key goal of eating and drinking before exercise is to optimise fuel and hydration levels and to make an athlete feel well prepared for the exercise ahead. There is also now evidence that the nutrients consumed prior to exercise may impact on muscle protein synthesis following exercise.
The right time to consume foods before training or competition will vary depending on when the exercise is to take place. It is generally recommended that consuming a "main" meal about 2-4 hours prior to exercise will prevent any gastrointestinal issues arising; however, if an athlete is training or competing early in the day, or planning a long exercise session, then a small meal or snack 1-2 hours before exercise may be advised.
Carbohydrate ingestion throughout resistance exercise has also been shown to promote steady blood sugar levels and higher glycogen stores. It is important to consider what the athlete will tolerate best, as some athletes have no problems consuming sports drink and a sandwich during an event while others struggle even to drink water without experiencing gastrointestinal issues. Nutrition plans should be based not only on the type and length of exercise, but also on the individual needs and preferences of the athlete.
Research in sports nutrition over several decades has identified how different nutrients can enhance exercise performance, improve recovery and modulate training adaptation. This knowledge has subsequently led to the development of specific sports foods. Sports foods are specifically formulated with the aim of helping individuals achieve specific nutritional or sporting performance goals and are designed to supplement the diet of athletes rather than to act as the main source of nutrition.
The vast majority of these specialised sports foods are simply convenient packages of nutrients that might be easily accessible to an athlete when required. In fact, athletes can often receive the same benefits from consuming these nutrients in regular foods. In many instances, regular foods may actually provide a cheaper, albeit less convenient, alternative.
Nevertheless, sports foods may have a role to play in an athletes diet. For example, we know that consuming protein after resistance training enhances subsequent muscle protein synthesis. Many foods that are good sources of high quality protein, such as meat, chicken, eggs and dairy foods, require refrigeration and can be difficult to access after a training session.
A protein powder that can be mixed with water is an example of a sports food that could be more convenient for an athlete to take to training and then consume immediately after exercise is completed. However, with thoughtful planning it is possible for an athlete to obtain all the nutrients they require through regular foods. For example, high quality protein in eggs or chicken leftover from the previous evenings dinner could be brought on a sandwich in a cooler bag with an ice block to keep cool until after training.