Casein protein vs. Whey protein: What protein to take, when, and why.
I’ve heard a lot from people regarding when and why they take whey or casein or simply get it from alternative protein sources. One I hear frequently is that bodybuilders eat cottage cheese or take casein before bed to prevent muscle breakdown while they sleep. The rationale is that casein is a “slow” protein whereas whey is a “fast” protein. But, is one source of protein better than the other? Is there a benefit from consuming whey post-workout and casein at other times? Let’s examine the facts.
First, the bad news: research can’t tell us the answer to every question. From the current body of literature, it isn’t possible to determine exactly how much protein each person needs after a workout and at specific times of the day (after all, people vary and so do their workouts and genetics) so they maximize their training while minimizing waste (in the form of money spent on food or protein supplements). But, we do know a lot about the amino acid content of various proteins and which ones increase muscle protein synthesis (which, over time, should result in strength and mass gains).
Both whey and casein are milk proteins and both are high in the protein digestibility corrected amino acid score (PDCAA is a measure of the digestibility of a protein and the amino acids necessary for an adult – a higher number is better). Additionally, both are high in total BCAAs (the ones that are especially important for boosting muscle growth and decreasing muscle breakdown). But, take a look at how these proteins stack up on PDCAA and one of the key BCAAs, leucine:
As you can see, whey is the highest in leucine. However, there are actually relatively few studies that compare casein and whey head-to-head. Here’s what we know: studies show that 20 grams of whey protein, taken immediately before or immediately after resistance training results in a significant increase in muscle protein synthesis. The same amount of casein, 20 grams, has also been shown to increase muscle protein synthesis.
Now, what about longer term? In a 10-week study, 13 recreational male bodybuilders ate their normal diet and also supplemented with whey or casein (1.5 grams per kg bodyweight). By all means, whey came out ahead. The group given whey showed greater gains in strength and lean body mass as well as increased fat loss compared to the casein group. Pretty convincing yes, even though it was a small study.
So what’s the bottom line on whey vs. casein post-workout and which is the better supplement for athletes? Given what we know now, whey is better than casein for stimulating muscle growth.
Knowing that what’s the point of casein and can taking it right before bed increase muscle growth when you sleep? Casein has a high PDCAA, it’s well digested, and has a great array of amino acids. Additionally, casein has a longer lasting effect (the amino acids don’t peak immediately but instead peak over a period of time) and according to one study, casein delivered a longer lasting anabolic response, which is why many athletes and bodybuilders opt to take it before bed. Does it work to decrease muscle protein breakdown while you sleep and do you “lose” muscle while sleeping anyway? Possibly, but in all likelihood that depends on the person’s overall protein intake, training program, and general health. However, if you need to gain weight and build muscle, it may make sense to take something like casein, or a food rich in casein like cottage cheese, before bed.
If you do nothing else, and have ignored the explanation of how whey protein differs from casein protein above, follow these 3 points and you’ll see an increase in strength and lean muscle gains.
Phillips S. Wheying the Evidence on Dairy in Sports. The ISSN’s 2008 annual conference.
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