What type?

Whey

Whey protein is quick to digest and provides all of the protein building blocks - the amino acids. Our bodies cannot make some amino acids, and whey is ideal for meeting essential amino acid needs. Whey also supplies branched-chain amino acids (BCAA), and some research supports that they aid muscle recovery after hard workouts.

Casein

Compared with whey, casein is slower to digest, and results in a lower, yet more prolonged rise in blood amino acid levels, which may provide a particular advantage for body builders. At least one study supports that casein outshines whey in terms of promoting strength and lean body mass gains in people following a structured weight-training plan.

Rice

Rice protein is less likely to create allergic reactions than other proteins, and it comes from a plant, making it appropriate for vegetarians. Another potential advantage is that rice protein contains a high proportion of arginine, an amino acid that can dilate blood vessels, possibly enhancing blood flow to muscles. Rice is not a "complete" protein however; it doesn't supply all of the essential amino acids. Some products combine rice protein with proteins from sources like soy or milk to make it complete.

Egg

Egg protein is ideal for people who are looking to build new muscle. It has a very high protein efficiency ratio (PER), which is one measure of how well our bodies can use any particular form of protein. The higher the PER, the more efficiently our bodies can use that protein when we eat it. Egg is off the charts in terms of PER. Egg protein also is a complete protein, and is a good source of essential and branched chain amino acids. Egg protein powder is made from egg whites, and comes in a convenient, pasteurized powder form.

Soy

Soy protein is a high-quality plant protein that provides all essential amino acids, making it a good option for vegetarians. For the body to best utilize soy protein, vegetarians should also eat grain or dairy within a few days. Soy protein comes in two basic forms: soy protein isolate and soy protein concentrate. Soy protein isolate is the most highly purified form, and has a minimum protein content of 90%. Soy protein concentrate contains more carbohydrates, and has a protein content of approximately 70%. Concentrates tend to cost a little less, but if you find soy protein concentrate doesn't agree with you, try isolate, which is easier for some people to digest.

How much?

With protein, as with many nutrients, more is not always better. According to Dr. Doug Paddon-Jones, Associate Professor at the University of Texas Medical Branch and Director of Exercise Studies, "30 grams of protein appears to stimulate maximum muscle synthesis. For athletes, each meal and snack is a chance to hit the 30 gram mark, giving your body several opportunities each day to maximize muscle growth and repair."

Another reason to spread protein evenly through the day is simple efficiency. "Given that your body won't use much beyond 30 grams of protein at a time, it doesn't make sense to load up with more than this," says Paddon-Jones.

When?

• Breakfast-To support muscle building first thing in the morning, try trading traditional carb-heavy breakfast foods for more protein-rich options, such as a powder protein supplement mixed with milk and cereal.
• If you're heading into a long strength-training session-Sipping a casein-based protein supplement prior to and during your workout will give muscles sustained access to amino acids. If taken in the evening, casein can provide a steady supply of amino acids while you're sleeping.
• Immediately pre- or post-workout-Especially if your workout includes aerobic or circuit training, protein manufacturers recommend a whey protein-based liquid or powder supplement.