Do High Protein Diets Cause Early Death?

All food is not created equal. The burger served to you at McDonald’s is not the same as the organic, free-range patty you grabbed at your farmer’s market.

The foods you eat, should never been viewed in isolation. Just mashing together proteins, carbs, and fats in the meal can change the way you look, but the selections also might make a difference in your overall health. A meal consisting of vegetables, grains (if you have no issue with them), and high sourced protein is different than some curated meat pilled on a butter bun, with mayo added as a “fat” source.

A body that exercises—specifically with weights—is different than one that does not. It processes foods differently, ages differently, and protects (although can’t completely prevent) the body against a variety of health problems, such as diabetes, heart disease, and yes—cancer.

And a study that compares behaviors and tries to draw conclusions—when those behaviors are not controlled—should be used as a platform to ask better questions, not provide wide-sweeping, inaccurate answers.

This all sounds like common sense. When you read each one, you probably sit nod your head and don’t blink an eye.

But now it’s time to blink. Maybe twice.

A study in the journal Cell Metabolism published research that suggested—as headlines would have you believe—that eating a high protein diet in midlife (50 to 65) is linked to premature death. Or more boldly: high protein is as bad as smoking.

Choose your salacious headline, but the moment the information hit the mainstream, you could hear cows rejoicing and protein powder stock plummeting.

This study—like many others—has its flaws and unsubstantiated claims. But the study design (which was pretty good) did reveal a few things you might want to know about the protein in your diet.

Why You Should Still Eat Protein (And Should Not Overreact)

Let’s get the worst news out of the way. It’s irresponsible to blindly claim, “High protein leads to premature death.” Or say it’s as bad as smoking. That’s not what the study found. If it were true I’d run around the streets screaming at the top of my lungs, and try and go door-to-door and let the world know I’d made a mistake. But that’s not the case. Why? For starters, the study was epidemiological, meaning the design made it impossible to make that type of claim. For those of you who don’t have a background in research (or simply don’t care), this how these studies work: They take information (“data”) after the fact and then try to draw conclusions.

Understanding Epidemiology: From Nutritionist Alan Aragon

People have to remember that observational data (as opposed to controlled intervention data) is good for generating questions, not answers. It should be made very clear that the outcomes were determined via dietary recall, which is notoriously unreliable. Establishing cause-and-effect is impossible in epidemiology, which is uncontrolled and subject to multiple confounding variables (think of the implausibility of things like meat or eggs being linked to diabetes – yes, we’ve seen that in observational research).

This is not a causational study. Based on the way the study was designed, it’s impossible and irresponsible to say, “Behavior A leads to Result B.” That doesn’t mean we can’t learn anything from the results, but it does mean you can keep chewing on your steak as you read this.

What Did The High Protein Study Really Discover?

The study isn’t without merit. It was actually well designed, and the problem was less about the research and more about the shock-and-awe headlines they inspired. (Lesson as always: Let’s read the studies before we draw over-arching conclusions.)

The study split the participants into three groups: High protein (more than 20% of their diet), low protein (below 10%) and a middle group (because it’s nice to have someone who’s neutral).

Once the groups were established, they assessed what happened to these people over the course of 18 years and looked to see if any serious health factors—such as disease or death—was influenced by protein intake. Everyone in the study was either in a group of 50 to 65 year olds, or 65+ years of age.

The study found eating higher amounts of protein led to an increase in IGF-1 (insulin-like growth factor), a hormone that is usually associated with building muscle. In reality, IGF-1 is linked to any type of cell growth.

The study suggests (from a correlational standpoint) that eating more animal protein led to an increase in IGF-1, and that those increases linked to the mortality rates of those in the study. In other words, higher protein showed higher death rates for those between 50 and 65, but also showed improved lifespan after you turned 65.

If anything, this study opens the door for more research to determine the role between IGF-1, high protein, and mortality for those aged 50 to 65. There’s more evidence to suggest that high protein is linked to increases in IGF-1, and it’s probably worth more studies to understand why high protein and IGF-1 might play a negative role for that 15 year span, but then be a benefit for those older than 65.

What the study did not find was anything to confidently suggest that high protein = more death. Or that high protein is as bad as smoking. In fact, the geniuses at did their own review of this study and found that this research suggests a “2 to 4-fold increase in mortality” compared to a 20-fold increase in lung mortality for smokers. Big difference.

What Can We Learn from the High Protein, Early Death Study

Let’s start by doing what’s most important: We do not know if eating high protein leads to an earlier death. There’s nothing new to suggest that is a fact.

“The idea of laying blame on a single dietary factor such as protein intake in the pathogenesis of cancer – or any disease for that matter – is absurd,” adds Aragon. “The adverse potential of not getting enough protein (sarcopenia, compromised glucose control, lower immunity, brittle bones), especially in the aging population, far outweighs the risks of getting too much.“

If anything, we’re only left with more questions than answers, which really is a byproduct of how science works. Discover one piece of information, which creates new questions, and then follow-up research can help us learn more.

To help you eat protein with more ease, some of the flaws are very easy to identify.

There was no consideration of food sourcing. No consideration of exercise. No looking at what other foods the participants consumed.

Yes—the researchers will point out that they controlled for carbs and fats. But again, this was just bottom line and didn’t consider what types of food were consumed. Would anyone doubt that green + grains + organic chicken ≠ fast food burger + mayo + fries?

Those macronutrients (proteins, carbs, and fats) could be matched in those two meals, but if two different people ate those identical meals year-over-year for 18 years, I’m pretty sure I know whom I would bet on for better health.

More importantly, “there was no statistical accounting for confounders that I could find, and this is a huge issue in any study,” says Dr. Brad Schoenfeld, author of The Max Muscle Plan.

Consider the following analysis from Schoenfeld, and it quickly becomes obvious why the conclusions are overstated:

The researchers are lumping ‘animal protein’ into an entire group, but it very well could be other aspects of the diet that are having the impact other than protein. Were the meats processed? If so, could be something in the processing. How were the meats cooked? Could be due to carcinogens from overcooking the meats. What was the fat content and breakdown of the fat profiles (i.e. saturated, MUFA, PUFA)? This could be an issue. What about total caloric intake? There are so many potential confounding issues that it makes drawing any conclusions extremely difficult. Simply looking at data from observations can be very misleading.”

Schoenfeld was also quick to point out that most people who eat red meat tend to consume it at fast food restaurants. (Just look at the sheer volume of sales to understand how much red meat is devoured at all of these establishments.) And while it’s not a hard rule, most people who eat fast food consistently have other lifestyle factors that could impact overall health.

Maybe the most important takeaway is an increased awareness that the needs of your body might change during different phases of your life.

The main thing we have to realize—or at least entertain—is that the things that make us ‘jacked’ or ‘ripped’ may not also be the best thing for longevity,” says nutrition researcher, Brad Pilon, author of Eat Stop Eat. “Even optimal health guidelines when you’re young may not be the best for longevity, as longevity is all about maintaining a status quo by reducing cumulative cellular damage and debris.”

Pilon suggests that the biggest push from this research could be a greater investigation into whether there simply might be different protein needs throughout your life cycle.

The response is not necessarily to overreact and cut all protein, but instead consider what your body needs given it’s activity levels and goals, and then consider the sourcing of your foods and all other factors that lead to health.

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