Eat Casein to Lose Weight and Build Muscle
Casein is a dairy protein found in milk, yogurts and cheese that helps with weight loss, building muscle and keeping your smile strong. Casein is a 'slow' digesting protein which remains in the digestive tract and delays stomach emptying (Boirie et al. 1997, Dangin et al. 2001). This means you stay and feel full longer when you eat foods containing casein.
In contrast to casein, whey , the other dairy protein, is a fast digesting protein which your body uses soon after eating (Dangin et al. 2001). Casein and whey work together to provide a steady influx of amino acids for muscle growth (Tipton et al. 2014). People who eat high casein diets also burn more calories.
Casein + Whey = Muscle Building Dream Team
Eating a combination of whey and casein proteins, which is naturally found in dairy foods, may reduce body fat while increasing lean muscle. One study found that young men who took a protein supplement containing 40 g whey and 8 g casein while weight training increased lean tissue mass and decreased fat mass, when compared to men consuming either a 48 g carbohydrate placebo or 40 g whey protein plus 3 g branched amino acids. All groups increased in strength (Kerksick et al. 2006).
Picture: A creamy white Charolais calf stares down the camera. Milk protein is designed to give growing calves like him all the amino acids they need for strong bones and muscles. These same proteins can help you build muscle while reducing body fat. Charolais cattle are an French dual purpose breed originally used for draft, milk and meat.
Whey and casein work together well. When you add exercise the health benefits really increase. Untrained men consumed either a 20 g protein supplement (14 g whey and casein protein and 6 g free amino acids) or a dextrose placebo (sugar) along with a strength training regime.
The men chugging down the milk proteins had greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1, mRNA, MHC I and IIa expression, and myofibrillar protein, when compared with those consuming a dextrose placebo (Willoughby et al. 2007). All of these are indicators of protein muscle synthesis and anabolism.
Why Milk Proteins Fuel Anabolic Growth
Cow milk contains 3.3% protein; 82% of the protein is casein and 18% is whey protein. One liter of milk contains 32 grams of protein (26 g casein and 6 g whey). When casein is acidified by stomach HCL, it forms a protein clot in the stomach which delays digestion and helps keep you feeling full longer (Haug et al. 2007).
Casein is the primary protein in cheese and is one reason it is difficult to eat a lot of cheese (it fills you up so you feel full quickly). Casein may also help the body absorb calcium and phosphorus.
In contrast to slow digesting casein, whey proteins are absorbed quickly. The combination of these two proteins is ideal for anabolic muscle growth. Whey protein provides a quick hit of amino acids; while the casein protein digests slowly and adds additional amino acids over a longer time. This facilitates rapid muscle recovery after a workout while enabling sustained muscle repair and growth.
Men may particularly benefit from using a milk based protein supplement. Casein consuming male mice increased their daily running distance and have a greater capacity to increase cardiac mass in response to exercise when compared to soy eating male mice (Konhilas et al. 2015).
Men and women were fed either a 10% casein diet (10%, 35%, and 55% of energy as protein, fat, and carbohydrate, respectively) or a 25% casein diet (25%, 20%, and 55% of energy as protein, fat, and carbohydrate, respectively). After consuming the diet at home for 3 days the subjects got to spend the next 36 hours in a respiration chamber (whose resemblance to a spa is totally overrated).
People consuming the 25% casein diet had a 2.6% higher 24-hour total energy expenditure and a higher sleeping metabolic rate than did people consuming the 10% casein diet. In addition, the subjects were in positive protein balance and negative fat balance with the higher casein diet compared to the 10% diet.
Men and women eating the 25% casein diet had 33% greater satiety compared to the lower casein diet. Due to its ability to enhance energy expenditure, improve protein balance, increase satiety, and create a negative fat balance; a 25% casein diet may be useful for weight management (Hochstenbach-Waelen et al. 2009).
Respiratory chambers are designed to measure the amount of energy made and consumed by a person. The person stays in the chamber for a set period of time so the amount of energy that the person uses can be calculated. Respiratory chambers are designed to measure oxygen consumed, carbon dioxide released and urinary nitrogen excretion.
The respiration chamber used in this study was a 494 cubic foot room (assuming an 8 ft. ceiling height this room was about 8 ft. by 8 ft.). This small room is like an efficiency apartment with a bed, chair, desk, computer, television, DVD player, video cassette recorder, telephone, intercom, sink, and toilet.
Unlike an efficiency apartment, you don't get a shower. However, you do get a cool room that measures how much oxygen is consumed and how much carbon dioxide is exhaled by anyone stuck in it. In addition urine samples are collected from a delightful open air toilet and used to measure nitrogen loss. Using the urine and air data, researchers can calculate exactly how many calories are burned from which macro-nutrients (protein, fat and carbohydrates.
Interesting Fact: Casein may prevent tooth erosion. Casein protein, with or without fluoride, increased the strength and hardness of tooth enamel (White et al. 2011). It also reduced soft tissue loss.
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- Hochstenbach-Waelen A, Veldhorst MA, Nieuwenhuizen AG, Westerterp-Plantenga MS, Westerterp KR. Comparison of 2 diets with either 25% or 10% of energy as casein on energy expenditure, substrate balance, and appetite profile. Am J Clin Nutr. 2009;89:831-8. Pubmed. Full paper.
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- White AJ, Gracia LH, Barbour ME. Inhibition of dental erosion by casein and casein-derived proteins. Caries Res. 2011;45:13-20. Pubmed. doi: 10.1159/000322300