Actor Joe Manganiello of "Spider-Man," "Magic Mike," and "Justice League" fame is known for his ultra-defined abs and his love of smoothies made with whey powder, water, and banana to boost his bodybuilding.

But you don't have to be aiming for a cinematic physique to use whey powder to build and retain muscle, especially as you're losing weight, doing resistance exercises, or getting older.

Whey is a protein that separates out from milk when cheese is made. It contains the amino acids leucine, isoleucine, or valine.

So how much and what kind of whey protein might make sense for you?

• Some studies find there's a limit to how much whey is beneficial. As a rule of thumb, if you're a highly active person or you're on a weight-loss regimen and want to preserve muscle mass, then a daily intake of 0.45 to 0.68 grams for every pound you weigh should do it. If you're sedentary, aim for 0.36 grams for every pound. But if you are obese, do NOT follow these recommendations — they'll result in super-high doses. Take what you would if you were a BMI of 25 to 27.

• Folks who get gassy or bloated from whey proteins should try whey isolate or hydrolysate. Vegans can use a plant-based protein powder.

• If you have liver or kidney issues, be careful about increasing your protein intake without talking to your doctor.

Whatever form you choose, try adding it to pasta sauces, drinks, casseroles, and soups.