On the surface, this study appears to be one of the worst types of studies that still manages to get printed in the medical literature. It is a longitudinal study of food intake, with the methodology probably depending on food diaries. That is extremely unreliable methodology—does every single person write down every single thing they eat, in exact quantities? That’s hard to do, even when motivated by (for example) a desire to maintain a reasonable weight. So I don’t believe the study at all.
Some political agenda was apparent when the study authors claimed that plant proteins are not as damaging as animal proteins. Really? Your body can tell the difference when an amino acid is made by a plant instead of an animal using the exact same biosynthetic pathway??? I do know that some plant proteins can be structurally different in a way that makes them harder to digest, so they are not as high quality (i.e. digestible) as meat proteins, but still...
One real difference the study authors might have been seeing is the difference in diets, between people who eat a lot of fresh produce (and tend to be vegetarians or semi-vegetarian), versus people who eat a lot of dense foods (who tend to consume large amounts of meat and prepackaged foods to the exclusion of produce). But that is not a difference in WHAT is being eaten, rather it is a difference in PROPORTIONS of different macronutrients.
I have noticed that many of these studies that supposedly find that a favorite food causes all kinds of horrid disease is that they always compare strict “meat and potato” diets to diets that are nearly vegetarian; the difference in disease incidence is most likely a result of different proportions of macronutrients, and not from the meat, potatoes, soda, or any other single component of the diet.
I notice that the study authors do not recommend a change in the protein daily intake recommendations, which the FDA sets at 0.8 grams protein per kilogram body weight (or about 40-70 grams per day, depending on size; more, if you are highly athletic).
So, go ahead and enjoy your barbecued steak, ribs, chicken, etc. Just eat it in moderation—portions should be about the size of a pack of cards—and accompany it with a nice salad or heap of seasoned steamed veggies.
Check this link for more on this “study”, which I used for my comments above: https://news.usc.edu/59199/meat-and-cheese-may-be-as-bad-for-you-as-smoking/
This was published in Cell Metabolism which I’m NOT finding in the list of peer reviewed journals for biology.
Not so fast. Here is the actual study, as opposed to a media spin or USC press release.
That is not to say that the study cannot be criticized. This is the abstract:
Mice and humans with growth hormone receptor/ IGF-1 deficiencies display major reductions in age- related diseases. Because protein restriction re- duces GHR-IGF-1 activity, we examined links between protein intake and mortality. Respondents aged 50–65 reporting high protein intake had a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenu- ated if the proteins were plant derived. 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. Mouse studies confirmed the effect of high protein intake and GHR-IGF-1 signaling on the inci- dence and progression of breast and melanoma tumors, but also the detrimental effects of a low pro- tein diet in the very old. These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.