I’ve had complaints recently (you know who you are) that I haven’t done a science-y post for too long. So, here it is. I was inspired by the 250 dietary assignments that I just graded for an Intro to Nutrition class. I would surmise that 80% of the guys and a good portion of the girls wrote about their protein intake either being very high and as such, very good, or needing to be higher. A very large percentage also drank protein shakes, some up to 4 times per day. And I found myself writing the exact same thing, over and over and over… “You must love having very expensive pee!”
Got your attention? Good. Every dietitian has this rant at least once in their careers or they’d explode, so I at least wanted some of you to learn from it. (Lucky for me, I have an exam on protein metabolism next week, so I’m technically also studying in the process of writing this post.)
One serving of a general protein powder has 100 calories and about 20 g of protein. Containers can cost anywhere from $25 to $100 (yikes!). I also noticed while doing research that most protein powders are rated by taste on a scale of 1-10. None of the food I normally eat is rated, because it doesn’t need to be… because it’s food, not powder. And something I find funny is that a lot of the same people who use “Citrus Splash” flavored dust also are proud of their low intake of processed foods. But taste and content aside, is it really necessary?
It is well established that the average person, even one who exercises regularly, needs 0.8-1.0 g of protein/kg of body weight. That’s roughly 35-70 g/day, depending on size. The average American gets at least 15% of their calories from protein (which is right in the healthy range, in terms the relationship to fats and carbohydrates… not that it’s necessarily from healthy sources), which assuming they are eating 1750-3000 calories, is about 260-450 calories. At 4 kcals/g, that’s at least 65-113 g of protein per day, well above the necessary amounts.
I know your next question already. It’s always the next question:
“But I exercise a lot and I want to build muscle/lose weight/burn fat. So I need more protein, right?”
Technically… yes. But extensive studies demonstrate that the requirements only increase to 1.0-1.3 g/kg. If you’re in the Tour de France, you may need 1.4 g/kg (seriously, this study has been done). If you are a competitive body builder, that goes up to 1.8 g/kg, but a lot of these studies haven’t made it past the peer review process. Let’s look at these numbers in relatable terms. If you exercise a lot, you need 65-91 g/day. Tour de France? 56-98 g/day. If you’re a body builder, you may need 126 g/day.
If you are wondering what all those numbers mean, let me remind you that the average person (that’s not you, Mom) eats 65-113 g/day of protein. That’s well above the range for even strenuous exercise- it’s actually about 1.6 g/kg, which is up there with body builders.
Who does need protein supplements? People in negative nitrogen balance, i.e. they are breaking down and excreting more protein than they can take in. These people need up to 2.5 g/kg protein, which may be hard to get from food alone. What does that look like? Burns, fevers, wounds, dialysis, cachexia (muscle wasting along with disease or age), or prolonged fasting– and if you have any of these conditions, I very much hope you are under the supervision of a doctor and a dietitian, who will provide you with safe protein supplements should you need them!
Now, some of you may be worried that you’re eating too much protein. Don’t worry, unless you’re eating 3-5 g/kg (which is a lot, even with protein supplements) you’re fine. Over that level and you may be overworking the protein breakdown processes in the liver and kidney.
What happens to the excess, then? Protein isn’t stored for energy in the body, only used for structure or function purposes, unlike carbohydrates, which are stored as glycogen, and fats, which are stored as triglycerides. So hang on, this gets complicated. Some, but not much, dietary protein (that which isn’t immediately needed for some function or other) is used for energy. If you are consuming more calories than you need in the process of trying to eat a lot of protein, energy from protein will be used instead of energy from fat, which then is stored as triglycerides (i.e. you’ll get fat, not muscular). The rest of the excess protein is “deaminated” (the nitrogen is taken off), and the nitrogen becomes urea, which is- you guessed it- disposed of in urine (and sweat). Protein without nitrogen has the same elements as carbs and fats- Carbon, Hydrogen, and Oxygen. So that expensive protein powder just becomes C, H, and O plus urine. I could go into way more detail, but I assume I’ve lost most of my readers at this point, so I’ll stop.
So what’s the best way to approach protein intake? That’s easy! It’s also the same answer I give for just about every food-like product/trend/diet question I get- just eat food!! A chicken breast has about 30 grams of protein (note: more than a protein shake), costs less than a dollar, has lots of other naturally occurring good stuff like B6, Mg, and Iron, and will actually fill you up. If you are vegetarian/vegan, you can check out some of my other blog posts (I linked to 4 right there for you!) for ideas of how to get enough essential amino acids. There has been some muscle strength/size benefit shown from eating protein right after a workout, but none of these are long-term and the benefit may wear off after the muscles have become trained.
If you really love the taste of protein shakes, then I suppose you can use it as a meal replacement. Or, if you’ve been using them for a long time and haven’t gained any weight, than feel free to keep using them alongside your diet, just keeping in mind that any excess becomes very expensive waste product. Also, please choose the supplements carefully- some are classified by the FDA as “foods,” while others are “supplements,” which, like all other herbal/mineral/vitamin supplements, are not strongly regulated by the FDA. If you do choose to buy protein powders, please do your research and buy from a reputable, third-party-tested brand that has no history of contamination or false advertising.
In conclusion, if you want big muscles, eat food and train hard. No pain, no gain. No training, no growth. The end.