Protein shakes with water or milk?

Whether you’re looking to  lose fat or gain mass, you may find that supplementation with a protein shake can be helpful. While these protein-packed sports nutrition products vary slightly between brands, most tend to be high in protein, with minimal carbohydrates & fat. However, you can alter the nutritional profile of these shakes by mixing the powder with milk rather than water. 


One scoop of a protein shake mixed with water contains 110 calories, so mixing it with milk can dramatically alter the calorie content. A protein shake with 8 oz. of skim milk would contain 190 calories, while a shake made with 7 oz. of regular milk would contain 275 calories. Mixing with skim milk or water is preferable for weight loss, but you may wish to mix your shake with regular milk if you consume it for post-workout muscle recovery & gain. An hour-long weightlifting session burns 220 calories, so only the regular milk shake would provide enough calories to replenish your body & offer additional calories for muscle growth.


Protein shakes mixed with water are usually low in fat, with 2 g total & 1 g of saturated fat per serving. Adding skim milk to your protein shake would not increase the fat content, but using 8 oz. of whole milk would result in a protein shake with 11 g of fat & 6 g of saturated fat. This can be detrimental for your overall health, as too much saturated fat can increase your cholesterol levels. The American Heart Association suggests a daily limit of 17 g. A protein shake with 8 oz. of regular milk contains 38 percent of that amount.


Protein shakes made with water are low in carbohydrates, with just 1 g per serving. This makes protein shakes a suitable supplement for low-carbohydrate diet plans. However, adding milk can make these a poor choice for such diet plans, as a protein shake with skim milk would contain 13 g of carbohydrates & a shake with regular milk would contain 14 g. Research from the December 2010 issue of “International Journal of Sports Nutrition & Exercise Metabolism” indicates that carbohydrates are necessary for optimal exercise recovery, so protein shakes mixed with milk may be preferable to those made with water.


Although protein shakes with water are already rich in protein, adding milk can increase the concentration of this nutrient. Both skim milk & regular milk contain 8 g of protein per cup, so a protein shake made with either would provide 31 g of protein. This amount is about half of the daily suggested intake of 40 to 60 g.

  • Adding milk adds calories.
  • Adding milk adds insulin.
  • Adding milk adds flavor.
[note]Mixing milk with your protein shakes may offer an advantage over water not just because of the added grams of carbohydrates & protein, but because of the added protein type. Milk contains both whey & casein protein, while protein shakes typically offer only whey. According to August 2006 research from the “Journal of Strength & Conditioning Research,” combined ingestion of whey & casein is more beneficial for post-workout recovery than whey alone.[/note]

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