Whey Protein vs. Casein Protein

whey protein vs casein protein header

There are many proteins to choose from but here we are going to look at the 2 most popular kinds of protein. You may need either one depending on your goals…

All dietary proteins are not created equal. As we have stated in past issues, the quality and uses of protein are significantly influenced by its source (milk, egg, soy, etc.) and the physical and chemical treatments to which it has been subjected.

Right now, whey, a protein from milk, seems to be most bodybuilders’ first choice. Whey is great. Although it absolutely does not have a biological value (BV) of 157, as has been asserted, its makeup (a high percentage of essential amino acids, especially the branched-chain aminos leucine, isoleucine and valine), solubility, bland and easily flavored taste, and the many unique protein “fractions” it potentially contains (when processed without heat or acid) do make whey a top choice. So do the results whey protein produces in clinical and laboratory studies and, most important, in the gym.

However, the “other” milk protein, known as casein, is no slouch either, although some give it a bad rap. People who badmouth casein are ignorant of the facts or have a vested interest in competing products.

We’ve known for several years that when whey protein is taken on an empty stomach, it’s not used efficiently because it’s absorbed too quickly. Although whey does promote protein synthesis, a huge portion of its amino acid content is used for energy instead of building muscle. Furthermore, there are big differences in the quality of whey proteins; you can’t necessarily detect the differences by reading the labels.

Casein, unlike whey, is digested slowly with no wasting of its aminos. Casein doesn’t stimulate protein synthesis as strongly as whey, but it has a dramatic anticatabolic effect that’s missing in whey. Furthermore, combining casein with whey slows the digestion of whey, thereby protecting the latter’s aminos and helping to maximize their use in muscle protein synthesis. That’s one reason the combination of whey and casein
is the protein foundation for most of the top meal replacement powders.


One recent study by R.H. Demling and L. DeSanti made a direct comparison of whey and casein. The report, “Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers,” was published in Annals of Nutrition & Metabolism (44[1]:21-29, 2000) and indicated that casein was significantly better than whey in promoting fat loss and in producing gains in muscle and strength. Although the study had its flaws, it was far more believable and relevant than the study I noted in a previous column (March 2000) that touted the benefits of whey.

This particular investigation lasted 12 weeks and used 38 police officers (active patrolmen, not desk jockeys), who averaged 34 years of age, 218 pounds and approximately 27% bodyfat, as subjects. Participating officers were divided into three groups. One group of 10 officers was used as a control and was simply put on a diet that delivered 75-85% of the predicted calorie requirements for each individual’s age, size and moderate level of activity. This control diet contained a minimum of 0.8 gram (g) of protein per kilogram (kg) of bodyweight.

Another group of 14 officers was put on a weight-training program and on the same calorie-restricted diet. However, their diet contained 1.5 g of protein per kg of body weight, and it included 75 g per day (two drinks) of a protein supplement derived from whey.

The third group, also consisting of 14 officers, followed the same training program and high-protein described above, but obtained their supplemental protein (also 75 g per day) from a casein-based source. The two supplements used in the study were store-bought products well-known in the bodybuilding community,not special concoctions that people wouldn’t normally use.

In addition, all participants took a high-potency multivitamin along with minerals every day. All diets contained no more than 25% of total calories from fat. Seventy to 75% of calories were consumed during activity hours and the remaining 25% at the last meal and before sleep. At least two-thirds of carbohydrate intake was in the form of complex carbs.

Prior to the study, 70% of the participants consumed over 50% of their total calories just before sleep and less than 10% at the first meal of the day. Although carb intake was only 60% of total calories, half of that came from sugars and over half was consumed at the last meal of the day. Seventy-five percent had a protein intake less than the Recommended Dietary Allowance of 0.8 g per kg of bodyweight per day, and only 10% took any vitamins.

Weight training took place four days a week with each session hitting one of four major muscle groups for 30-35 minutes. Aerobic exercise was optional but had to be performed either after the weight training or on alternate days. Other specifics of the training program were not provided.


If you’ve been on the whey bandwagon, I think the results of this study are going to surprise you. All of the participants lost bodyfat. Even the control group decreased their bodyfat from 27% to 25% with the very modest diet they were put on. To put this in perspective, although officers in all the groups had been eating fewer than the number of calories they actually needed before the study began, their food choices and eating patterns had been poor (please, no doughnut jokes).


The group that consumed the whey supplement in addition to exercising went from 27% to 23% bodyfat, while the exercise plus casein group dropped from 26% to 18% over the 12 weeks. The average amount of fat loss was 2.5, 4.2 and 7 kg in the control, whey and casein groups, respectively for all three groups, that’s a high amount of fat loss in such a short time.

Somewhat surprisingly, no lean mass was lost in the control group despite their fat loss. Lean mass increased by 2 kg in the whey group and by a whopping 4 kg in the casein group. Strength measured as an eight to 10-rep maximum for the chest, shoulders and legs increased an average 29% for the whey users and 59% for the casein users.

These are some seriously impressive results in both supplemented groups, but especially in the casein group, regardless of the fact that the test subjects were relatively low-fit overweight individuals. Four kilograms of lean mass is close to a pound a week over the course of the research program.

This is only one study using a small number of individuals, and the casein used was the ultrahigh-quality undenatured variety; nevertheless, this research clearly shows that casein-based protein supplements make excellent muscle-building tools. As to which is ultimately better, casein or whey, there is as yet no definite answer, but why concern yourself with that debate? Use them both! I have said many times over and over, when it comes to protein, the most important thing is just do it… and lots of it. Consistently.You won’t be disappointed.

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Fitness Writer For IllPumpYouUp.com

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