Whey is a cheese-making byproduct that comes about when you separate the liquid from the curds. It delivers a powerful protein punch, is quick to digest and is loaded with branched-chain amino acids such as leucine. Research also shows that whey is better than any other protein at increasing muscle protein synthesis.
However, it does contain lactose, which is indigestible by some people and which can cause digestive upset.
Casein is a milk protein found in curds and is also chock-full of BCAAs. It ranks second to whey when it comes to muscle-building potential and digests more slowly, making it the perfect supplement for long periods without fuel, such as during sleep.
Some clinicians have found that having 30 to 40 grams of casein one to three hours before bed has a positive effect on building muscle and strength while preventing muscle breakdown.
Though eggs often get a bad rap, they actually are one of the highest quality proteins available. Egg protein is easily assimilated and digested and is second only to whey in terms of leucine content, making it a great dairy-free option for those with sensitivities or allergies.
Soy is a complete protein source and is great for those trying to build muscle on a plant-based diet. And if you’re able to tolerate dairy, research indicates that pairing the soy with a dairy protein source may benefit muscle building.
Even though hemp protein is derived from the hemp plant, it contains no THC — the compound in marijuana that causes a high. It is loaded with omega-3 fatty acids and has a number of essential amino acids. However, because it lacks the amino acids lysine and leucine, it is not considered complete.
This protein is derived from split peas, a high-fiber legume that is packed with muscle-building BCAAs. Pea protein absorbs more slowly than whey but quicker than casein, and it tends to make you feel fuller longer, perfect for a calorie-controlled diet.
Research has shown that leucine is the primary amino acid responsible for muscle protein synthesis after a tough workout — even when consumed on its own without other essential amino acids. Maximize your gains with leucine-rich foods such as eggs, red meat, chicken, fish, soy and lentils, as well as dairy like nonfat milk, Greek yogurt, Swiss cheese and cottage cheese.