Ever wonder what’s really in that protein shake you just ordered? Sure, it may taste great, but if you don’t know what’s in it and choose wisely, that scrumptious beverage could undo your efforts to be healthier or to lose weight.First of all, make sure what you’re drinking actually is a protein shake, advises celebrity dietician Ashley Koff, R.D. That means one with healthy and adequate sources of this important nutrient. “Make sure you’re not compromising on quality, so look at what the source of protein is,” suggests Koff. MORE: Are You Getting Too Much Protein?Your best bet is to stick with whole food sources of protein whenever possible versus highly processed forms. Organic soybeans, whole pea, sprouted quinoa, hemp, sprouted brown rice and egg whites are all excellent, healthy protein sources for your shake.When it comes to the amount of protein you should get, more is not always better. Ideally, you want six to 15 grams of protein in your shake. Some will have as much as 20 to 30 grams, but there’s no way your body is going to absorb all of that, notes Koff. Likewise, anything less than six grams is not a decent source of protein.So how can you be sure of what you’re getting? One easy way is to make them yourself. But when a blender, your favorite milk and some fresh produce are not available, pre-packaged shakes or restaurant ones can be a convenient option—just be aware of the ingredients. Some manufacturers and restaurants pile in the additives to make your shake more palatable, even though raw, simple ingredients can taste awesome all by themselves. (Yet another reason to check the label.)MORE: Are Your Taste Buds Primed to Detect Fat?For people who don’t have time to get their protein intake through food or want a quick recovery drink after a workout, protein shakes are a good alternative, according to nutritionist Keri Glassman, R.D. What’s more, protein can aid in weight loss. Recent research published in the journal Cell found that digested proteins create a chain reaction in the digestive, nervous and circulatory systems that leave you feeling full hours after eating. That long-lasting satiety helps you eat less later on, which can mean a lower—or at least a steady—number on the scale.Of course, portion control is also key. If you routinely down your protein shake with a meal or as a snack when it’s really just a milkshake in disguise that can backfire by causing weight gain.MORE: Trick Yourself Into Eating Less“Many protein shakes have as many calories as a full meal, and some could even have a whole day’s worth,” warns Glassman. “Keep in mind: Are you using a protein shake as a post-exercise snack or as a meal replacement? Take note and monitor what you are drinking.”Or just drink less—and enjoy each sip.