The nutrient builds and repairs muscle after your workout, but studies are now linking too much protein to health dangers like heart disease. So, now what? Shape investigates.
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It’s no big secret that protein is crucial for fit women. “It contains essential amino acids that help create muscle, maintain bone health and keep blood pressure in check,” says registered dietitian Nancy Rodriguez, a professor of nutritional sciences at the University of Connecticut in the US. The nutrient can also help keep you slim. Protein is slower to digest than carbohydrate, so a relatively small amount will keep you full for hours. Plus your body actually burns calories in order to digest and use it.
There seems to be a clear-cut case for the benefits of protein, but here’s where things get complicated: A growing body of evidence indicates that you can have too much of a good thing.
“High amounts of protein can increase your level of growth hormone, insulin and Tor, an enzyme that accelerates ageing, all of which may promote tumour growth,” says Valter Longo, a professor of gerontology and biological sciences at the University of Southern California.
His research found that adults who get more than 20 per cent of their total calories from animal protein have a four times greater risk of dying of cancer than those who get less. Loading up on the nutrient can also increase your chance of heart disease, according to a study in the Journal of Internal Medicine.
The key words in this research are animal protein, however. Scientists are finding that the type of protein you eat can make all the difference.
In a study in the Archives of Internal Medicine, for instance, a higher intake of red meat, especially the processed type, was associated with cancer and cardiovascular death. (Meat lovers were also less likely to be physically active and more apt to have a poor diet overall.) Eating less-processed types of protein was linked to a lower risk of mortality.
So where does that leave you and your diet? “Animal protein is the most complete kind because it has the nine essential amino acids in the correct proportions that your body needs to function,” says Donald Layman, a professor emeritus in the Department of Food Science and Human Nutrition at the University of Illinois in the US.
“To get the health benefits of protein, you should focus your diet on lean meats, poultry, fish, eggs and dairy, but eat high-fat and processed meats sparingly,”
Plant-based protein delivers different nutrients than the animal type, but it doesn’t usually contain all nine essential amino acids in the amounts we need.
Luckily, the fix is simple. Nancy says to combine plant proteins to make up the difference. For example, top spelt (11g of protein per cup) with black beans (8g per half cup), or add peanut butter (4g per tablespoon) to oatmeal (6g per cup).
But watch your calories. “An 85g serving of chicken has around 21g of protein and 200 calories,” she says. “Getting that much from peanut butter is going to cost you about 600 calories.” Lighter options exist, though, such as edamame, Greek yogurt and tofu.
YOUR PROTEIN PLAN
Now that you know what sources of protein to eat, how much should you aim for without going overboard?
The recommended dietary allowance is 0.8g of protein per kilogram of body weight – meaning a 63kg woman requires at least 50g a day, an amount that most adult women hit easily, according to the US Department of Agriculture. “But that’s the absolute minimum, the lowest amount you should consume to prevent a deficiency,” Donald says. “Most people need more for optimal health and muscle maintenance.”
That’s especially true for women who exercise regularly, because their bodies require extra protein to build and repair muscle. “Active women should try to eat 1g to 1.5g of protein per kilogram of body weight a day,” says sports nutritionist Andrew Jagim, an assistant professor of exercise and sports science at the University of Wisconsin-La Crosse in the US. For a 60kg woman, that’s 60g to 90g daily.
To determine exactly how much you need within that range, consider the type of workouts you do.
If you take barre or yoga classes a few times a week, go for the low end, Andrew suggests. If you’re training for a marathon or triathlon, shoot for the top. Recreational runners, bikers, swimmers and those who spin or take other tough cardio classes should try for the middle.
Whey and pea protein powders give you the most benefits post -workout.
Eating salmon for lunch doesn’t mean you can skip protein at dinner. Aim to eat 20g to 30g at each meal.
TIME IT RIGHT
Eat some protein at each meal and snack rather than consuming most of it at dinner, which is what many people do.
“Your body is breaking down muscle all day long,” Nancy points out. “Eating the bulk of your protein at dinner can’t make up for the damage that occurred earlier.” Plus your body can utilise only so much of the nutrient at once. When you eat a day’s worth in a single sitting, some of it goes to waste.
Active women should consume 20g to 30g of protein at each meal, based on their weight, Nancy recommends. (The smaller you are, the fewer grams you need.)
That’s the equivalent of an 85g to 110g portion of lean red meat, poultry or fish, a three-egg omelette with 28g of cheese, or 140g of cottage cheese topped with 28g of almonds. If you prefer to have several small meals, shoot for 10g to 20g of protein at each meal for a daily total of 60g to 90g.
Make sure to have a protein-rich meal or snack after your workout to boost muscle recovery, Andrew advises. You don’t have to chow down with in 30 minutes of your sweat session to get the benefits, as you’ve probably heard.
If you can’t grab something right away, it’s fine to wait up to two hours to eat, he says. So stretch, head home and take a shower. Then grab some cheese and a handful of nuts, and get your protein fix.
SHOULD YOU USE PROTEIN POWDER?
If you’re short on time after your workout, this powder is a healthy, convenient way to boost your intake of protein. Opt for whey protein powder, which is milk-based, suggests Andrew Jagim, a sports nutritionist. “It has the highest amount of amino acids, and your body digests it quickly, so you get the benefits almost immediately,” he says. If you’re lactose intolerant or a vegan, try pea protein powder, which is similar to whey in terms of the protein it contains. But check calories and sugar content. “Choose a powder that has 100 to 150 calories and less than 4g of sugar per scoop,” says registered dietitian Brooke Alpert, the founder of B Nutritious, a nutrition counselling company in New York City.