Protein...the dangerous macronutrient?

Have you seen this? It’s just about impossible not to this week.

“Too much protein in middle age is as ‘bad as smoking.’” (source)

“Too much animal-based protein could lead to early death.” (source)

“Deli Dilemma: Meat and Cheese Linked to Earlier Death.” (source)

I sometimes wonder if these people actually look at the research they are reporting, because I do, and it’s really very disappointing. You would hope that something as significant as the statements above would hold some substantial truth to them- they’re BIG statements to broadcast; but unfortunately there are SO MANY HOLES in the research (probably something larger then holes….) that there should barely be a conclusion at all.

The general public is already terribly mystified about what the hell is happening at the grocery store, and now we’re telling them that eating chicken every night is the same as dragging off that cigarette?  Pleassseeee…..let me wake up from this nightmare.

  So what caused these headlines to pop up all over the place this week? This month there was a study published in the Journal of Cell Metabolism that sparked the flame. Here’s a play by play of what it entailed…

·           18 years ago a little over 6,000 participants filled out a 24-hour diet recall form. According to their answers/food intake on this form, they were spilt into 3 groups dependent on their protein intake (low/moderate/high) on that specific day.

·           18 years later (fast forward to the present), the causes of mortality were looked at for this group of people (that at one point filled out a 24-hour diet recall form). They looked at cardiovascular mortality, cancer mortality, diabetes mortality and all cause mortality.

·           A little over 2,000 of these participants had their insulin-like growth factor 1 (IGF-1) level tested, although the circumstances in which this happened were not reported.

·           Then….to follow up that study, they did one in mice. The researchers hypothesized that eating protein increased IGF-1 and examined if it would increase the rate of growth in already present tumors in mice.

 You can see the abstract here, but have to pay for access to the full article. If anything the pictures of the mice they included are a nice touch. The full article may come up here if your interested.

 A few of their conclusions:

  “Overall, our human and animal studies indicate that a low protein diet during middle age is likely to be beneficial for the prevention of cancer, overall mortality, and possible diabetes through a process that may involve, at least in part, regulation of circulating IGF-1 and possibly insulin levels.”

  “We also propose that at older ages, it may be important to avoid low protein intake and gradually adopt a moderate to high protein, preferably mostly plant based consumption to allow the maintenance of a healthy weight and protection from frailty.”

I know that was a lot to get through but this is why it’s important to QUESTION what the media to telling you. Here are my issues with this “research.”

  • I’m not a mouse. If there are any mice reading this please let me know, I’d like to talk to you about your protein intake. Mice traditionally eat a LOW protein diet; so yes when you feed them a high protein diet (that they naturally aren’t meant to be eating) there may be metabolic consequences. I’m not saying that humans were meant to eat high protein diets, but we can’t rely on mice to tell us otherwise.
  • Have you ever filled out a 24-hour dietary recall form? It’s really considered the CRAP way to get a good picture of someone’s overall dietary habits. Basically you would tell me right now everything you ate yesterday, that’s right- JUST ONE DAY. Based on what you told me you ate yesterday, I would then make conclusions 18 years from now about your diseases processes and mortality. I hope there wasn’t a barbeque, birthday party or buffet at work yesterday (that’s really going to put a damper on that conclusion). Dietitians are now taught other methods to get a better picture of someone’s overall dietary status; I don’t know anyone that still uses a one-day diet recall to assess someone nutritionally. Would you want what you ate for just ONE DAY to be used in substantial research about your mortality?
  • This is not a study that proves causation. It’s looking at a relationship, that the authors should comment on, but not make drastic conclusions from (like they have). Another type of study that would look at a RELATIONSHIP, but not a CAUSE, would be television viewing and rates of cardiovascular disease and diabetes. If those who watched the most television had the highest rates of diabetes and cardiovascular disease, would that mean that the television was CAUSING the disease? Or would it possibly mean that those people who tend to watch more hours of television also tend to be less active and live less healthy lives compared to those individuals who watch less television? Topics like diet and lifestyle are multifactorial, you cannot draw drastic conclusions from one factor.
  • Do people who eat more meat tend to live less healthy lives? Possibly yes and no. I know people who eat a lot of animal protein…they also don’t exercise as much, drink more alcohol, eat LESS fruits and vegetables and MORE processed foods then I do. Does that mean that because I eat the same amount of animal protein as they do we are in the same risk category for cancer, diabetes and cardiovascular disease? NO. NO. NO. None of these other factors were considered in this study and conclusions. You can see below what my "typical" protein intake is, ~20% of my usual caloric intake. This would place me in the "high protein" group, at the "highest risk" for cancer according to their research. Almost ALL my carbohydrates come from vegetables (some starchy) and fruit (organic), my fat from HEALTHY fats, and my proteins from lean sources (mostly free range/organic/grass fed)- I would consider myself at LOW risk when just looking at my food intake.


  • A HUGE problem with this type of research is that it was NOT initially created to look at the topic of protein. The researchers had to rely on the simple questions that were asked originally and missed MOST of the deaths (and a lot of other factors that may have had an impact). If you look at the facts provided in the supplemental data there were only 113 determinable deaths in the total cohort of 6,381 (that’s less then 2% of the people surveyed originally).  113 out of 6,381? Really?
  • Part of their conclusion is that higher levels of IGF-1 is what’s increasing our risk for cancer…what about other things that increase IGF-1? EXERCISE is the main one that comes to mind. The other culprit was circulating insulin, which your pancreas releases ANY TIME you eat carbohydrates.

A closing message from one of the researchers (who by the way has an equity interest in a large plant protein medical food company).

“We provide convincing evidence that a high-protein diet, particularly if the proteins are derived from animals, is nearly as bad as smoking,” says the University of Southern California's Dr Longo.

I still can’t believe he would say something like that; the damaging effects of smoking are well documented and substantial- this study proves no where near that.

I know that nutrition/food/vitamin/health studies are extremely hard to complete and do appropriately; but this doesn’t mean that we get to jump to conclusions with the ones that are done poorly.

Here’s what I take from this all this “protein = smoking” nonsense-

1.     As always, MOST your plate should be vegetables (organic, non-gmo when possible).

2.     If you want to eat animal protein- do it- but still eat a varied diet. If you don’t want to eat animal protein- don’t- but still eat a varied diet.

3.     I always recommend good quality animal proteins- grass fed, free range, organic (sometimes possible/sometimes not), etc. These types of animal protein have a different composition and nutrient value compared to conventionally raised animals.

4.     Don’t eat processed, cured meat. There’s nothing there for you except chemicals that you don’t need.

5. Don't SMOKE.

6.     Question nutrition news in the media. I'm not saying it's always wrong, but it's definitely worth looking at before you make any drastic changes in your diet/lifestyle.