Traditionally speaking, whey is the liquid left over when milk is curdled. It is made up of water, sugars, fats, and protein. When people in the fitness community talk about whey, they're more than likely referring to whey protein, which is made by extracting and drying the protein fraction from this liquid.
What is Whey Protein made of?
Whey protein generally comes from cow's milk. After casein, whey proteins are the second most abundant class of proteins found in milk, and account for 20% of all dairy protein. Proteins are made up of amino acids, which are used by our bodies for a huge number of functions including growth, repair, hormone and neurotransmitter production, and naturally, making our own protein.
Whey is not a single type of protein. The term whey actually refers to a collection of water soluble globular proteins that are found in whey, which all have individual names. These include beta-lactoglobulin, a protein of unknown function which is thought to exist entirely as a food source, alpha-lactalbumin, which is important in milk synthesis, serum albumin which acts as a carrier protein, and immunoglobulins, which mediate immune function in the animal. Whey also naturally contains small amounts of proteins like growth factors, enzymes and nutrient transporters. These proteins don't retain their functions when they are ingested as whey protein by humans because they are broken down by processing, and then again by digestion.
What is Whey Protein Used For?
Whey is one of the most complete proteins available, it is very well absorbed by the majority of people, and it is rich in muscle building branched chain amino acids (BCAAs), which makes it ideal for people looking to supplement their protein intake. There are a number of reasons people might want to do this.
Because we use protein and amino acids for so many functions within the body, a certain level of consumption is required to maintain good health. This level increases as a person becomes more active. According to the guidelines used by the Australian Institute of Sport, a sedentary adult should eat between 0.8-1 g of protein per kg bodyweight per day, while someone engaged in resistance training, an energetic sport like football, or endurance training needs up to 1.7g per kg bodyweight (1). This means an active 80kg man needs to eat up to 136g of protein per day just to maintain health and condition. For some people, particularly those people with busy lifestyles, it can be difficult to get sufficient protein through diet alone. For example, one 30g serve of good quality whey packs the same amount of protein as a 100g steak, and is a lot easier to prepare on the go. Vegetarians have to be particularly vigilant about their protein intake because plant foods are typically less concentrated in protein than meat or dairy. Whey can make it easier to maintain a healthy vegetarian diet.
Protein has a demonstrated role in weight loss. Protein foods require more energy to digest than fat or carbs – this is known as the 'thermic effect', and it means that calorie for calorie consumed, protein will provide the body with less energy than fat or carbs. On top of this, protein is filling, so it can help curb the appetite. This is one reason that high protein diets, such as Atkins, have become hugely popular for weight loss. Finally, protein helps build lean muscle. Muscle is metabolically active tissue, so it needs a lot more energy at rest than fat. This is the reason why people with more muscle in their bodies actually have a higher metabolism than those with more fat, even if they're equally as active.
The last two points touched upon the relationship between protein and muscle, but muscle building is probably the main reason people use whey protein. A certain amount of protein is required to maintain a steady state of health, but to actually build muscle, your body needs a lot extra. Some people suggest that the best muscle building results are seen when protein amounts as high as 3g protein per kg of bodyweight per day (240g of protein per day for an 80kg man) is ingested in conjunction with a good training schedule and proper nutrition.
What is Whey Protein Powder Good For?
Because whey is a fast absorbing protein, it is great for a quick protein hit. This makes whey ideal straight after a workout to give your muscles what they need to recover and grow, and first thing in the morning, to tip your nitrogen balance back into the positive after more than eight hours without nutrition, but whey is versatile enough to be used any time.
This versatility extends beyond physiological effects. Whey has a very mild, neutral flavour. It is usually sold as a flavoured powder which mixes into a milky shake with the addition of water or milk, but unflavoured whey is available, and can be used to boost the protein content of savoury foods like soups and stews. Both flavoured and unflavoured varieties can be incorporated into baked goods, smoothies and desserts.
What is Whey Protein Concentrate?
Concentrate and isolate are both terms which describe the method by which whey is extracted and purified.
Whey protein concentrate is the least processed of the two types of whey protein. It is typically 60-80% protein by weight, and contains higher levels of fat and carbohydrate than whey isolate. This is the main disadvantage of whey concentrate, even though these amounts aren't huge, and most whey concentrates contain less than 10% of each by dry weight. Although whey concentrate is absorbed quickly when compared to proteins like casein and egg, the extra fat and carbs, and the fact that the proteins are often less denatured, or broken down by the purification process, helps to slow down digestion, meaning that whey concentrate can provide the body with a slower drip-feed of aminos, which can help maintain a positive nitrogen balance for muscle building and be advantageous for weight control. In addition, whey concentrate is the cheaper form of whey protein
What is Whey Protein Isolate?
Whey protein isolate is a highly purified form of whey which typically comes in at more than 90% protein by weight. Because it lacks the extra sugars and fats that whey concentrate contains, and tends to be broken up more during processing, whey isolate is absorbed by the body very quickly. Whey protein isolate contains next to no lactose, so it is a great option for people who suffer from lactose intolerance.
Whey protein hydrolysate is a type of whey protein isolate that has been further digested or 'hydrolysed' into smaller fragments, for even faster absorption and easier digestion. Because of the extra processing and high purity, whey protein isolate is more expensive than whey concentrate.
Whey protein is most commonly found as a blend of isolate and concentrate, which combines the fast acting properties of whey isolate with the slower digestion and good value that whey concentrate represents, although whey isolate and hydrolysate are popular post-workout proteins. Protein blends commonly feature other proteins, including casein and egg, peptides, and single amino acids.
Whey is a fantastic foundation supplement, and you'd be hard pressed to find a bodybuilder who didn't consider it to be and essential part of their diet plan.
(1) AIS. Protein. Australian Sports Commission. Australian Government. http://www.ausport.gov.au/ais/nutrition/factsheets/basics/protein_-_how_much. Accessed April 8 2015.