"U.S. and Italian researchers tracked thousands of adults during nearly two decades and found that those who ate a diet high in animal proteins during middle age were four times more likely to die of cancer than contemporaries with low-protein diets — a risk factor, if accurate, comparable to smoking. They also were several times more likely to die of diabetes, researchers said."
Paleo is NOT about meat. Paleo is MODERATE meat consumption, low to moderate carbs, and HIGH FAT. Many of the Paleo gurus have stated many times that 2/3s in weight in a plate of food is supposed to be veggies, not meat. And yet, many Paleo dieters thought that Paleo was about huge steaks. It isn't so. Yes, Instagram is filled with pictures of such huge steaks, but Paleo as described by the gurus, is NOT high protein. So for all we know, this study might be correct (although it measured protein also from bad quality animals/eggs, farmed fish, unfermented dairy etc -- stuff that Paleos aren't supposed to eat).
Being talked about elsewhere… interesting to point out that actual rates between their cohorts actually favor high protein groups as dying less from cancer. Some modeling and statistics later… the opposite result… not only the opposite result, but 4x the rate? Wow, that's some model they've got there.
A lot of insignificant associations there too… a lot of the hazard ratios are nonsense and not significantly different between groups.
You don't even need to evoke arguments about the remainder of the diet. Seems likely they massaged the data to tease out conclusions they wanted. (Who doesn't do that though?)
Look up AGEs. These people are most likely flash frying beef (you should slow cook red meats for the most part). It's also probably they were not eating fruits and veges. They may have smoked, not exercised. Where they health concious meat eaters? Unlikely. Its almost impossible to control for every variable with studies like this (well actually it is pretty much impossible, who knows what they are eating, or doing), which is why one should be wary of firm conclusions from them, especuially if they have no proposed model (a model is fully testable, this kind of loose correlation is just kind of neither here nor there as scientific hypotheses go).
Here's the full article.
The researcher is wandering pretty far from his area of expertise - insulin/IGF1 pathway - and here is studying a 2006 population data set with average age of 65. It appears that all-cause mortality over 18 years was 40% of the study group, about 2500 total deaths, very few of which would have been middle aged participants. The only striking relation between high protein and increased mortality was with diabetics, yet these only account for 2.5% of total deaths in total, or 60 people. Hardly the protein horror that Washington Post and CNN make it. Especially when the author concludes that the elderly - most of the study group - should eat more protein. And he acknowledges that a much larger study is needed because of the insignificant diabetic population size.
How did we get from "Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population" to "Too much animal protein could lead to an early death" - oh, right sensational pro-vegan propaganda headlines! That's how.
Yeah, well, it's commonly known too that fasting turns on autophagy (and obviously turns off IGF-1) and leads to less cancer.
You'd probably get the same effect with an all wheat diet if the mice were allowed to eat in excess vs being calorie restricted, although of course, if they were overfed protein, that would lead to toxic effects. "Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65, but a 5-fold increase in diabetes mortality across all ages." - after all we know that excess proteins get converted to glycogen, hence the link to diabetes.
You could overfeed them with soy protein and still get the toxic effects of too much protein (unless the tryspin inhibitor in soy was left, in which case they wouldn't be able to digest all the protein, which would mislead the folks running the study to assume that plant proteins are safe and meat proteins are dangerous.) They mention soy, but not this "Analogously, when soy protein intake was reduced from high levels to low levels, we observed a 30% decrease in IGF-1 (p < 0.0001)"
So, if anything a) this is a study promoting CR and IF, and b) that overeating proteins causes conversion to glucose, which in turn raises IGF-1.
There's maybe a tiny blurb in there about plant protein in the highlights:
But then, here's the gem:
"Although there was a trend for an effect of substituting the same level of animal protein with plant protein on IGF-1 and IGFBP-1, the differences were not significant. These data suggest that lower protein intake may play a role in decreasing cancer incidence and/or progression in part by decreasing IGF-1 and increasing the IGF-1 inhibitor IGFBP-1. Additional studies on various types of animal- versus plant-based proteins are necessary to determine their effect on cancer, IGF-1, and IGFBP-1."
So if anything it says we saw some tiny differences between plant and animal protein, but more studies are needed as they weren't significant - the exact opposite of what the WaPo headline claims.
If anything, the researchers should be lambasted for the lie in highlights, and WaPo for not reading the whole study... (did they "accidentally the whole"?)
(Mice are one of the few creatures that are adapted to eating raw grains without harm.)
I don't doubt it if the meat is coming from antibiotic&hormone ridden, infected, factory produced meat. This is not what our ancestors ate, and (hopefully) is not what the paleo person's diet is centered around. Aim for local, grass fed, humane meats, and try to talk to the person who raised them. Well raised meats have been said to have a much higher nutrition value than factory and store bought, and in my experience are much fresher and tastier. These studies conducted that are overly-publicized shouldn't be a very trustworthy source to go by, either.
A nutritionist from the UK wrote a review of the study. I highly recommend reading it. http://www.zoeharcombe.com/2014/03/animal-protein-as-bad-as-smoking/