If you're American of a certain age, you constantly received the dietary message to make protein the focus of every meal. And the more protein, the better! You still may worry about getting enough protein in your diet.
So when we hear about the benefits of a plant-oriented diet, your first question likely is “Geez, how will I get enough protein?”
Too Much of a Good Thing
There are many historical & economic reasons for our preoccupation with protein. Today, however, the facts just don't justify our fears: In the U.S., whether meat-loving or vegan, all Americans consume similar levels of protein at around 70g/day (1). This is WELL ABOVE the recommended level. The RDA's guide for the optimal - NOT minimal – protein daily requirement is 56g/day for men & 46g/day for women. (2)
Unless you are on a severely calorie-restricted diet or very ill, you will not be deficient in protein. Have you ever run into anyone with Kwashiorkor? Me neither. Take this off your worry list, please!
It doesn't help that we are bombarded with market messages that feed our protein fears. This is not science, this is fashion. Our market economy is merely responding to & pushing consumer demand. In 2012 new product introductions with high protein claims were 3 times greater in the US than anywhere else & accounted for 19% of new product launches. (3) Keep an eye out for the next food trend on the horizon: Plant-based proteins are cropping up in processed foods as the latest new entrants on the high-protein bandwagon.
Remember, we've seen this all before during the '80-90s with the explosion of low-fat products (which merely reduced fat in favor of sugars & refined carbs). Regrettably, that trend spawned our current epidemic in obesity & diabetes. We're currently in the throes of high-protein & gluten-free product pushes. Don't be seduced by the latest nutritional hype or trend. Instead, look to peer-reviewed research evidence & scientific consensus to guide your food choices.
So What's the Harm?
Excessive protein consumption isn't like having extra money in the bank. We can't store much of it. What we don't use, we have to excrete. So there's a cost: The more excess protein we consume, the higher our risks of overtaxing our kidneys & livers, & damaging our bones. Excess protein increases our risks for chronic kidney disease & kidney failure, hepatic diseases, diabetes, osteoporosis, gout, kidney stones, gallbladder disease, constipation, weight gain & more.
We often ignore our kidneys until we discover they've been irreparably impaired. Kidney disease is on the rise, impacted by obesity & diabetes which all stem from our diet & sedentary lifestyle. Between 1980 and 2009, the prevalent rate for end-stage renal failure increased nearly 600%, from 290 to 1,738 cases per million. (4)
If you are chasing protein, making it the focus of your plate, or worse yet, supplementing with processed protein powders, shakes & bars, you are putting yourself at even greater risk.
Food's a Package Deal
While excessive protein is problematic whatever its source, there are important differences in how plant vs animal proteins are metabolized in our bodies & impact our long-term health.
Food is a package deal: In addition to protein in meats/fish/poultry/eggs/dairy, you also get saturated fats, cholesterol, & growth hormones like IGF-1. These are inseparable. Consumed together, they give rise to chronic systemic inflammation – the root cause of all our leading killers, heart disease & many cancers. Even a single meaty-fatty meal injures the endothelial function of our arteries measurably. (5)
There are many mechanisms that cause this slow, constant low level of inflammation, year in and year out, overtaxing our immune systems & promoting disease. For example, bacterial endotoxins, abundant in meat & dairy, survive cooking & promote inflammatory responses in our arteries & exacerbate insulin resistance (6). Sulfur-rich amino acids in animal foods give rise to gut bacteria that provoke inflammation in our intestines & arteries, which is linked to atherosclerosis, heart failure, kidney disease, kidney failure, stroke & death. (7)(8)
Plant proteins, conversely, uniquely contain fiber, phytonutrients & on average, 64 times the antioxidant power of animal foods. (9) Together, they effectively quench systemic inflammation & oxidative stress, which is why plant-dominant populations the world over (like the Okinawans, who consume less than 10% of their total calories from animal sources) traditionally have suffered very low levels of those chronic illnesses that are rampant here.
For these reasons, favoring plants on our plates is salutary & very effective at preventing & treating chronic conditions.
Protein Combining - Another Myth
And by the way, since all myths have an odd ability to persist, you may still run across the caution that plant proteins must be combined on your plate to fulfill your nutritional needs. That notion has long since been debunked & disavowed. As long as we favor a diversified plant-oriented diet, including vegetables, whole grains, fruits, legumes with some nuts & seeds, we need have no fear that our protein needs are not being met.
The Elephant in the Room
There is one nutrient, however, that 97% of Americans ARE seriously deficient in: fiber! Found only in plant foods, our severe deficiency in fiber puts us at serious risk for developing chronic diseases.
In 2015 the Dietary Advisory Guidelines Committee cited fiber as a nutrient of concern for Americans (but not protein!). We'll examine fiber's importance & impacts on health next time.
S Rizzo, K Jaceldo-Siegl, J Sabate, G E Fraser. Nutrient profiles of vegetarian and nonvegetarian dietary patterns. J Acad Nutr Diet 2013 113(12):1610 – 1619
Food and Nutrition Board, Dietary Reference Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2002/2005)