In recent years, we've gotten it into our heads that (A) protein is magic and (B) more is always better. We've attached a host of virtues to the nutrient — slimming! energizing! filling! gluten-free! — and given it a health VIP status.
"People don't want carbohydrates because they're afraid carbs will make them fat, and they don't want to eat fat because of heart disease, so what's left that's safe to eat? They assume just protein," says Mary Ellen Camire, PhD, past president of the Institute of Food Technologists and a professor of food science and human nutrition at the University of Maine.
Protein also happens to have a smart PR team: an industry dedicated to making sure you know that it's the hottest ingredient in the nutrition world right now. Labels touting "high protein" or "2x protein!" are showing up on fortified cream cheese, salad dressing, snacks, even desserts. More than half of grocery shoppers have bought protein-enhanced food at least once, according to a report by the NPD Group, a New York research firm. But experts say we shouldn't be fooled by all the pumped-up products. "One nutrient can't turn junk into a functional food," says David Katz, MD, director of the Yale University Prevention Research Center. "Adding protein to a dubious recipe is like putting lipstick on a pig."
On the plus side, a quarter of us now regularly check protein grams on nutrition labels — a habit that's up 38 percent since 2004.
"Overall, the increased awareness around the importance of protein is more good than bad," says Melina Jampolis, MD, immediate past president of the National Board of Physician Nutrition Specialists. "It's just that you can get too much of a good thing, as with healthy fats or anything else."
We all need to put protein in its proper place, as one important player in your diet (as opposed to the only good guy on the team). Take a look at the science to put together your perfect protein plan.
Let's Back Up: What Is Protein, Exactly?
As the protein you eat travels through your digestive tract, it breaks down into amino acids, which are absorbed into the bloodstream. These amino acids are the same building blocks of protein that make up our cells. We manufacture some in our bodies, but nine essential amino acids have to come from our diet. Sources such as poultry, meat, fish, eggs, soy, quinoa, and milk contain all nine, so they're often referred to as "complete" proteins.
Our bodies require these amino acids from food to build muscle, produce hormones, and repair tissues — including skin, collagen, bone, blood plasma, and the lining of our intestinal tracts. Every day, old or damaged cells die off and must be replaced or rebuilt with fresh amino acids.
But replacing those amino acids doesn't require a lot of special food or nutritional know-how. Most Americans are already getting enough in their diets, says Wayne Campbell, PhD, a professor of nutrition science at Purdue University. The Institute of Medicine (IOM) has set the acceptable range of protein intake between 10 to 35 percent of your daily calories.
"The average American comes in between 14 to 16 percent," says Campbell.
Protein and Our Pursuit of Slimness
Why do so many of us believe we need to shovel in more protein — in the form of extra meat and cheese in our salads, powered-up smoothies, and fortified products — to meet our quota? The protein-in-everything trend can be traced back, at least in part, to the weight-loss industry, says Jampolis.
The Atkins diet (heavy on steak and hunks of cheese) was huge in the late 1980s and early '90s, followed by the South Beach craze. Once two significant studies in the early to mid-2000s came out showing that people lost more weight on low-carb, high-protein diets, protein's rep as a slim-down magic bullet was secured.
Some of this good buzz is well-deserved, experts tell us. Protein has an advantage when you're trying to lose weight: Digesting it requires extra energy. That means you actually burn more calories to process protein than you do to process carbs and fat. And "without a doubt, protein is the most satiating macronutrient; after eating it, you have a very strong signal from your body that says, 'You're full; you can stop now,'" explains Stuart Phillips, PhD, director of the Centre for Nutrition, Exercise, and Health Research at McMaster University in Ontario. But — big caveat — people can and often do eat straight through the fullness signal, says Jampolis. Listening to your body and good-sense portion sizes are both key to success.
Not All Protein Is Equal
Sure, a Big Gulp-size protein shake or a bacon cheeseburger both supply the nutrient, but "it's not good to be focusing on protein in isolation," says Walter Willett, MD, chair of the nutrition department at Harvard's School of Public Health. You can't ignore other factors, like calories, sugar, and saturated fat. The Nurse's Health Study found that a higher intake of red meat, for example, was linked to a 22 percent increased risk of breast cancer. Conversely, women who ate lots of vegetable protein (such as from seeds, beans, and soy) had a 30 percent reduced heart disease risk and 20 percent lower risk of type 2 diabetes.
When you dig in to your food matters as much as how you get your fill. Most of us in the U.S. eat very little protein at breakfast or lunch and then overload on it at dinner, says Phillips. It's better to get some at every meal, especially as we get older, so that our bodies always have a supply at the ready. See "A Sample Day" (opposite) for ways you can space it out.
When High Protein Backfires
We can't just eat protein by the truckload. The IOM places the safe upper limit at 35 percent of your total calories — and going over that amount could mean you're missing out on key vitamins, minerals, and fiber. Plus, too much protein can lead to…
Weight Gain: "Excess calories, whether from protein, carbs, or fat, have one place to go — into 'storage,'" says Katz. Protein feeds body fat, like anything else. Explains Jampolis: "If you add protein and don't cut calories elsewhere in your diet, you'll gain weight."
Digestive Issues: People on extremely low-carbohydrate/high-protein diets can end up with constipation, bad breath, and even bad body odor, says Ashley Koff, RD. These are all signs of ketosis, a metabolic state your body goes into when you drastically cut carbs.
Increased Risk for Heart Disease and Cancer: We've long known that digging into lots of red meat boosts your chances of heart disease, and new research shows that consuming 1.7 ounces of processed meats daily — equal to four strips of bacon or one hot dog — can boost a person's baseline risk of colorectal cancer by 18 percent.
A High-Sugar Diet: If you're relying on protein-fortified convenience foods like bottled shakes, bars, and snacks, you're downing a whole lot more sugar than you think, says Koff. Some protein bars have as much sweet stuff as a candy bar.
Clearly, protein is good for us. Very good. But we all need to be smarter consumers — and reach for whole foods over supplements, and healthful proteins over fatty or highly processed ones.
"This trend is bad if we start thinking more is always better," warns Katz. "But if our new awareness is accompanied by an understanding of how and where to get protein — that plants can provide it — and how much is enough, it can be a good thing."
This story originally appeared in the September 2016 issue of Dr. Oz The Good Life.
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