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Q: Can protein powders help me lose weight?
A: The short answer is, “Yes.” But before I talk about protein powders—which are, after all, just a great delivery system for protein—I need to first explain why the heck protein is so important.
Protein: The Crucial Macronutrient
The word protein comes from the Greek and means “of prime importance.” It’s an accurate description. Without dietary protein, your body starts breaking down precious muscle tissue, literally “eating” itself.
Among its many responsibilities, protein helps make enzymes, hormones, antibodies, and about a zillion other things your body requires to optimally function.
I’ve long been a fan of higher-protein diets for fat loss. Dietary protein has far less of an effect on insulin than carbs, is more satisfying, and requires more energy (calories) to break down and assimilate. That’s why I refer to protein as your magic bullet for fat loss.
Protein Keeps You Satiated
Because your body demands protein, your appetite-control mechanisms (which send messages from your gut to your brain signaling that you’ve eaten enough) work beautifully with protein (with carbs … not so much). Simply put, eating a protein-rich meal keeps you fuller longer.
You’ve experienced protein’s satiating effects before. Recall a time when you ate a big bowl of pasta. A few hours later, you were probably hungry again—and most likely craving more carbohydrates! Now, think about a time you had a lean chicken breast or maybe a sirloin along with some green veggies (and maybe half a sweet potato). You probably didn’t think about eating the rest of the evening. And though you didn’t realize it at the time, you probably ate less during that meal.
Studies prove this. One in The American Journal of Clinical Nutrition found a high-protein breakfast trumps hunger far better than a higher-carbohydrate diet. That’s because in addition to suppressing your hunger hormone ghrelin, a higher-protein breakfast increases levels of cholecystokinin (CCK), a hormone that tells your brain that it’s time to stop eating.
Ever wonder why you refrain from overeating eggs, but can’t put the brakes on the glazed donuts? Now you know. And when was the last time you ate just one bowl of sugary cereal while watching reruns of Friends?
Protein at breakfast, in fact, can curb hunger and cravings throughout your day. One study in The American Journal of Clinical Nutrition found a high-protein breakfast reduced evening snacking and otherwise curbed hunger in overweight and obese teenage girls.
Protein-Rich Diets Provide Sustained Fat Loss
Protein has less of an effect on insulin than carbs do, is more satisfying, and requires more energy (calories) to break down and assimilate. A greater ratio of protein to carbohydrate at a meal stabilizes blood sugar and reduces insulin response. And research by Donald Layman, PhD, and others suggests that leucine—an amino acid found in protein—specifically helps you to maintain muscle mass while losing body fat during weight loss.
In a study in The American Journal of Nutrition, Layman compared a high-protein, low-fat diet with a low-fat diet. No contest: the high-protein diet helped retain muscle mass and dissolved fat far better than the low-fat diet.
But a diet means absolutely nothing if you can’t keep that weight off long-term. Therefore, a follow-up study published in this same journal looked at how people respond to a high-protein diet over 12 months. Again, the high-protein group felt fuller, more satisfied, and had more energy than the low-fat group. More people on the high-protein diet lost a good amount of weight and kept it off. Also worth mentioning: the high-protein group had improved triglyceride and triglyceride/cholesterol ratios compared with the low-fat group, both of which are risk factors for heart disease.
Choosing the Best Protein Sources
I recommend that every meal and every snack contain adequate protein. And when I recommend a high-protein diet, I don’t mean an all-protein diet. In addition to proteins, incorporate plenty of veggies, low-glycemic fruits, healthy carbs like quinoa and sweet potatoes, and nuts and seeds.
Protein powders are a terrific way to get high-quality protein into your diet. They’re fantastic for morning smoothies, as pre- or post-workout fuel, or any time you need to take the edge off appetite. But which ones should you use? All proteins—and all protein powders—are not created equal. Vegetarians and vegans, take note: some plant-based proteins have an inferior amino acid profile compared with animal proteins. That’s not necessarily a bad thing; it just means you’ll want to include plenty of higher-protein plant foods like quinoa and legumes in your diet.
In a recent USDA study, researchers randomly assigned 90 overweight or obese adults to one of three groups, all of whom supplemented their regular diets with a drink. One group drank whey protein, one drank soy protein, and one drank the same number of calories as carbohydrates.
At the end of the 23-week study, those drinking the carbohydrate shake had actually gained about 2 pounds, most of it fat. Those drinking the soy protein shake stayed the same. (However, I did find another study showing that soy protein powder altered metabolism in a way that helped with weight loss.)
But those drinking the whey protein drink lost about 2 pounds. And while both other groups saw essentially no change in their waist size, the whey group actually lost about an inch around their middles. Interestingly, those in the whey protein group had significantly lower blood levels of the appetite-stimulating hormone ghrelin than those in the carb or the soy groups.
If you’re vegan or sensitive to dairy, pea protein powder is a great choice. Frequently, you’ll find it blended with other vegan-friendly proteins like brown rice protein. Pea protein has an impressive amino acid profile and provides good amounts of leucine, an important amino acid for fat loss.
Jonny Bowden, PhD, CNS, aka “The Rogue Nutritionist,” is a board-certified nutritionist and the best-selling author of 13 books on health, most recently The Great Cholesterol Myth (FairWinds Press, 2012). Visit him at jonnybowden.com and follow him on Twitter @jonnybowden. Do you have a health question for Jonny? Send it to firstname.lastname@example.org. Write “Health Q&A” in the subject line.