Middle-aged? Put down the meat
March 5th, 2014
09:12 AM ET

Middle-aged? Put down the meat

Eating a high-protein diet in middle age could increase your risk of diabetes and cancer, according to a study published this week in the journal Cell Metabolism. But don't stay away from meat for too long - the same study showed those over 65 need more protein to reduce their mortality risk.


Insulin-like growth factor 1, or IGF-1, is a protein in your body related to growth and development. Past studies have linked IGF-1 to age-related diseases, including cancer. Mice and humans with higher levels of IGF-1 often have a higher risk of developing these diseases.

Scientists believe protein intake plays a role in IGF-1 activity. Eating less protein, studies have shown, can lead to lower levels of IGF-1 in your body. So theoretically, protein consumption could be directly linked to disease incidence and death.

The study

Researchers analyzed survey data from 6,381 U.S. men and women aged 50 and above to understand the link between protein, certain diseases and mortality.

The study participants were split into three groups: a high-protein group who ate 20% or more of their daily calories from proteins; a moderate-protein group who ate 10 to 19% of their calories from proteins; and a low-protein group.

Researchers also looked at the differences in risk between those aged 50 to 65 and those over 65 years old.

The results

People between the ages of 50 and 65 who ate a high-protein diet had a 74% increase in overall mortality compared to those in the low-protein group. The meat lovers also had four-fold increased risk of dying from cancer during the study's 18-year follow-up.

However, this risk was only seen in those who got their protein from animal sources such as meat, eggs and cheese; the link disappeared if the protein came from plants, such as nuts, seeds and beans.

People who were over the age of 65 and ate a high-protein diet saw the opposite effect. Researchers saw a 28% reduction in death from all causes in this group. Cancer deaths in this older, high-protein group, were also reduced.

Study participants of any age who ate a high-protein diet had a five-fold increased risk of dying from diabetes.

The scientists had IGF-1 data for more than 2,200 people in the study. Analyzing this information, they determined that for every IGF-1 increase of 10 ng/ml, those on a high-protein diet were 9% more likely to die from cancer than those on a low-protein diet.

The study authors concluded that high levels of animal proteins cause increased levels of IGF-1 and possibly insulin in the body, which leads to higher mortality for people ages 50 to 65.

Tumors in mice

Researchers also reported on a separate experiment, where lab mice were either on a high-protein or a low-protein diet. Mice on the low-protein diet had a lower cancer rate than those on a high-protein diet, even after being implanted with 20,000 melanoma cells. The low-protein mice also had smaller tumors on average than those on a high-protein diet by the end of the six-week experiment.

When the mice were switched from a high-protein diet to a low-protein diet, researchers saw a 30% decrease in their IGF-1 levels.

“Almost everyone is going to have a cancer cell or pre-cancer cell in them at some point. The question is: Does it progress?” study author Valter Longo said in a press release. “Turns out one of the major factors in determining if it does is protein intake.”


Eating more than 10% of your calories from animal proteins in middle age could increase your risk of dying from diseases such as cancer and diabetes. But after 65, you may need that extra protein to protect your body from becoming frail.

“The majority of Americans are eating about twice as much proteins as they should," Longo said. "It seems that the best change would be to lower the daily intake of all proteins, but especially animal-derived proteins."

Walter Willett, an epidemiologist at Harvard's School of Public Health, says not much should be made of this study's findings. It's unreasonable to treat "animal protein" as one class, he says, as fish, poultry and red meat are all very different.

Willett also noted that the headline on the press release associated with this study - "Meat and cheese may be as bad for you as smoking" - is a vast overstatement. The researchers did not include data on smoking in their study.

The Institute of Medicine's Food and Nutrition Board recommends eating about 0.8 grams of protein per kilogram of body weight every day in middle age. So a 160-pound person should eat about 55 to 60 grams of protein a day.

soundoff (502 Responses)
  1. Dennis

    Live longer but just wish you were dead.

    March 5, 2014 at 14:55 | Report abuse | Reply
    • truebob


      March 5, 2014 at 16:18 | Report abuse |
    • thomas stone

      no doubt,and this just in,EVERYBODY DIES! EVEN VEGETARIANS! I think they believe they live forever.My grandfather lived to 94.My grandmother is 90 and neither one is a vegan,but hey I guess they don't count in the study.

      March 5, 2014 at 17:20 | Report abuse |
    • mrl

      Yep Yep Yep

      March 5, 2014 at 19:03 | Report abuse |
  2. jack2

    beans is a huge source of energy but it gets your sphinxter flappin.

    March 5, 2014 at 14:57 | Report abuse | Reply
    • Jan

      Long soak followed by thorough rinsing and then removing any froth that appears on top when you bring the beans to a boil greatly reduces the legendary flatulence effect of beans, "the musical fruit." Toot-toot!

      March 5, 2014 at 16:00 | Report abuse |
  3. Bryn

    Whole food plants wins any debate.

    March 5, 2014 at 15:03 | Report abuse | Reply
    • Jesse

      Too bad muscular atrophy becomes a problem. I have yet to see a vegan/vegetarian who has anything but a sickly look to them.

      March 5, 2014 at 15:43 | Report abuse |
    • MC2323

      You have yet to meet a vegetarian without a sickly look to them? I know literally dozens personally. Healthiest people I've ever seen.

      March 5, 2014 at 16:52 | Report abuse |
    • JR

      Jesse, you have apparently met a VERY small pool of vegetarians. I am vegetarian and anything but sickly. 2X conference wrestler of the year in HS. I also wrestled in college, and participate in rock climbing and crossfit now as a 30 year old male in great shape and a significant muscle mass. A vegan or vegetarian or someone who also eats meat can ALL be unhealthy if their diet is unhealthy and unbalanced. However, any of them (though much tougher for a true vegan) can be balanced if the proper nutrients are still being achieved. There is nothing "sickly" tied to vegetarianism unless you simply have a poor diet and no exercise...but that can happen with a meat-including diet as well.

      March 5, 2014 at 17:02 | Report abuse |
    • ehomer

      Ha. My middle aged vegan husband is a muscle bound beast. 6'2", 210 lbs of pure muscle. He works out every day. My whole life I've known vegetarians (& more recently vegans) who all look better than their meat eating counterparts. Check out Mac Danzig, just for one. Look at Jared Leto in Fight Club.

      March 5, 2014 at 17:20 | Report abuse |
    • Really?

      as long as you don't mind looking like a human praying-mantis. Real men eat meat. I hate skinny stick men.

      March 5, 2014 at 19:51 | Report abuse |
    • JR

      What about eating meat makes a man a "real man"? I eat meat a few times a year. I'm mainly a vegetarian but I don't restrict my hosts if I go to someone else's house to eat dinner etc. But on a regular daily basis I eat no meat. I squat 2X my body weight, I bench 2X my body weight, I rock climb, I do cross fit, etc. I LOVE being active and you would never guess my regular diet has 0 meat in it if you were looking at me. I'm not sure what about that makes me less of a man. And stickly? No comment haha.

      March 6, 2014 at 10:12 | Report abuse |
  4. The Truth

    One study is nothing more than random data set with no real value by itself. It only becomes credible when the study can be repeated by several different independent studies. If it is not repeatable than it is a quirk or an invalid study. Yes, you can stack the deck in a study to have the outcome be what you want it to be. That is why others need to be able to repeat your findings, expecially those who set out trying to disprove you.

    Now that vegans are in glee over studies like this, what would they do if it is disproven? Even better would they start eating meat if there are studies showing veganism is harmful and unhealthy?

    March 5, 2014 at 15:07 | Report abuse | Reply
    • Dazzy

      The vegans are too busy scrambling to find meat after countless studies have proven how unhealthy a vegan diet is.

      March 5, 2014 at 15:18 | Report abuse |
    • Leigh

      There will not be such a study, because eating vegetables and fruit is more healthy.

      March 5, 2014 at 15:43 | Report abuse |
    • Jesse

      Eating fruits and vegetables IS healthy but a healthy human also needs meat based amino acids for a truly healthy body and healthy functions.

      March 5, 2014 at 15:52 | Report abuse |
    • Donnie the Lion

      Meat is great.....to a point. But guess what? As you get older, your body changes how it processes certain foods....and meat is one of the most prominent in this category. My hometown is very meat-centric, very into hunting. Restaurants offering healthier choices have gone out of business pretty quickly. Guess what? Lots of 300-400 dudes, shufflilng around town and dying early (40-55) from heart disease, diabetes, and cancer (yes kids, there is a link between obesity and cancer whether you choose to believe it or not).

      No thanks. I'd like to live past 55.

      March 5, 2014 at 19:22 | Report abuse |
  5. wuzzup

    Ha, Ha. I can see all the diabetics thinking to themselves, "First they tell us "low carb". Now, the tell us "low protein". What's left to eat?...Pig skin and bacon grease?"

    One apple, one avocado, sweet potato and a handful a spinach...Exercise, everyday... a good night's rest...get some sun...finally, walk in your backyard in your bare feet. That's as simple as I can make it.

    Sick people are so gullible...and, so pathetically adamant that they tried "everything" and nothing works. Keep taking those pills, fools. It'll work, someday! Ha Ha!

    March 5, 2014 at 15:10 | Report abuse | Reply
    • Really?

      Look out for the fire ants

      March 5, 2014 at 19:47 | Report abuse |
  6. TheOne

    everything gives you cancer/diabetes now a days so you might as well keep eating it

    March 5, 2014 at 15:18 | Report abuse | Reply
  7. ug

    If you want to eat it...do it...non of anyone's business how you live your life...libs are always telling you how to live...heII they have an answer to everything...

    March 5, 2014 at 15:22 | Report abuse | Reply
    • Jung

      Sounds like projection to me.

      March 5, 2014 at 16:10 | Report abuse |
  8. Yoda

    Insurances companies ought to charge meat gorgers a higher premium like they do for smokers.

    March 5, 2014 at 15:23 | Report abuse | Reply
  9. Wuzzupgarbage

    Another useless study with useless diatribe...mine included.

    March 5, 2014 at 15:25 | Report abuse | Reply
  10. tetch

    Anyone consider that maybe there are other things in the meat, eggs & cheese besides proteins contributing to the issues?

    March 5, 2014 at 15:30 | Report abuse | Reply
    • Sean T

      haha, that's exactly my thought on it....this is dumb and generic and too broad a theory being proposed here...

      I love it. eat carbs. no wait carbs are bad, eat protein. wait, don't eat too much though. don't eat carbs or protein. uh wait, take vitamins, oh no, wait, vitamins may be bad or ineffective...uh.... hold on.....

      March 5, 2014 at 15:44 | Report abuse |
  11. Conrad Miller

    And in another year, they will totally refute and reverse this report.

    March 5, 2014 at 16:04 | Report abuse | Reply
  12. J Robinson

    You will feel better and become healthier if you don't eat food produced and sold in the US.

    March 5, 2014 at 16:04 | Report abuse | Reply
  13. Mike White

    What is the point of living longer if you are reduced to a miserable science project?

    Eat & drink what you want, when you want, die when your time comes. Have no regrets.

    March 5, 2014 at 16:06 | Report abuse | Reply
  14. GIUK

    With all the additives, antibiotics, etc. in the US meat supply is there any real meat left in that meat?

    March 5, 2014 at 16:09 | Report abuse | Reply
  15. Mike

    If you don't eat your meat, you can't have any pudding...

    March 5, 2014 at 16:11 | Report abuse | Reply
    • Dan

      "How can you have any pudding if you don't eat your meat?"

      I see what you did there...

      March 5, 2014 at 17:22 | Report abuse |
    • mr68gto

      You can't have any pudding if you don't eat your meat. PF

      March 5, 2014 at 18:35 | Report abuse |
  16. tony

    This is a poorly written article on a poorly conducted study. When the article says "meats" i think it is meaning red meat(which has been linked to cancer and other diseases). Getting rid of simple and refined carbs will be more valueing for us middle-aged folks than worrying about protein.

    March 5, 2014 at 16:31 | Report abuse | Reply
  17. Khayla

    Is it really necessary for scientists to induce such suffering in animals, such as mice. Infecting them with melanoma, and watching as their tumors kill them, in order to tell people that meat is bad for them, again? I mean, there have been so many studies utilizing animals, to prove so many times that meat is bad for us. Just how many more studies and tortures are needed??? Can't these experiments be eliminated, and instead, an alternative, that provides the answer to a reasonable degree of certainly implemented instead?? Sometimes I wonder how we will be perceived in the generations to come...we know so much about animals, their intelligence, anatomy/similarity to humans, that continuing to torture them in these labs makes absolutely no sense to me. And frankly, it is disgusting. We as humans should put a stop to continuing to look to science for answers such as meat is bad, exercise is good, this chemical is bad, this chemical is good. I think we all have a pretty good inner feeling of what is good, bad, harmful to us.

    March 5, 2014 at 16:35 | Report abuse | Reply
    • Shawn

      ^^^ What!?!? WHAT?!?! WHAT!?!?!?

      March 6, 2014 at 07:23 | Report abuse |
  18. Bill

    As a bodybuilder who is middle-aged, I consume at *least* 1 gram protein per pound of body weight each day. Protein is necessary to rebuild muscle tissue after working and tearing the muscle fibers. I'm not exactly sure what happens to the protein if the muscles haven't been worked, but perhaps many middle-aged people aren't working their muscles as much as they should.

    March 5, 2014 at 16:39 | Report abuse | Reply
    • Really?

      Precisely. Its all about the exercise.

      March 5, 2014 at 19:53 | Report abuse |
  19. ewfjcopwaef

    The multibillion-dollar organic/heatlh/natural food industry is the biggest scam in the history of food production, preying on ignorant, irrational suckers who fall for their marketing hype.

    March 5, 2014 at 16:41 | Report abuse | Reply
  20. Jane

    Sorry but the medical community is clueless when it comes to diet. Sugar is what will kill you first. Stop eating crap. That's the best diet...

    March 5, 2014 at 16:51 | Report abuse | Reply
  21. MysteriaKiito

    Growing old is already taking away my greasy food and sweets. You'll have to pry meat out of my cold dead hands.

    March 5, 2014 at 16:52 | Report abuse | Reply
  22. Rick

    10% of your calories from meat. Mmm... so where does the other 90% come from? Starches, carbs and sugar. That sounds like a recipe for middle age obesity and diabetes right there.

    March 5, 2014 at 16:52 | Report abuse | Reply
  23. Sue

    I wonder what this study would have shown had the meat eaters been divided into those who ate only organic,non gmo grass fed cattle, and those who ate hormone and antibiotic gmo grain fed cattle. I am a vegetarian by choice, but do not believe that a small amount of non adulterated meat is unhealthy.

    March 5, 2014 at 17:01 | Report abuse | Reply
  24. oaksavanna

    This morning I read that studys show it is sugar not fat that causes heart disease, cancer, demensia, diabetes, obesity etc. Fat (as long as it isn't trans fat) is now supposed to be good for you. It's a protectant. They had peer reviewed studies to prove it. Now I am reading this article that says meat is bad for you. Why? What specifically is in the meat that is bad if fat is now supposed to be good?

    March 5, 2014 at 17:04 | Report abuse | Reply
    • Tyler

      Ignore this article and study as it is bogus. If you read the study it says that they were put on controlled diets for 24 hours and then received a follow up 18 years later to see how they died, and drew conclusions from there. Not how a legitimate study should be conducted.

      March 5, 2014 at 17:27 | Report abuse |
  25. JR

    sigh. So many people here who think that all vegetarians are stickly, unhealthy and unhappy. I have no problem with other people eating meat in their diet. Partake in whatever diet works for *you* as long as it keeps you healthy and avoid the obviously poor diet choices like excess sugar and processed foods. But don't buy into the vegetarian stereotypes that the ignorant crowd has. They are just as bad as the "all meat eaters are unhealthy crowd".

    March 5, 2014 at 17:12 | Report abuse | Reply
    • Really?

      "processed foods" are processed for a reason

      March 5, 2014 at 19:48 | Report abuse |
    • JR

      so? I'm missing your point here. It is not hard to avoid processed foods on any regular basis. I know that processed foods are processed for a reason, I also know that sodium is added to a lot of food "for a reason". Does that mean I have to eat it?

      March 6, 2014 at 10:07 | Report abuse |
  26. Greg

    Usual faulty, misleading reporting on this topic: "But don't stay away from meat for too long – the same study showed those over 65 need more protein to reduce their mortality risk."

    As if meat is the only way to get enough protein. Absolutely not true.

    March 5, 2014 at 17:14 | Report abuse | Reply
  27. Arrakis

    Some studies say cut the fat. Other studies say cut the carbs. Other studies say cut the protein. Geez! What's left?!

    March 5, 2014 at 17:16 | Report abuse | Reply
  28. Skull

    "Broccoli's a side dish, folks. Always was, always will be, OK!"

    March 5, 2014 at 17:19 | Report abuse | Reply
  29. Dan

    My grandfather ate meat every day of his life and loved bacon. When he was 85 I saw him pick up a 200 pound boat motor. He lived into his 90s.

    Liberals want everyone to be a sissy, and it's not working, so they keep putting out articles like this.

    March 5, 2014 at 17:33 | Report abuse | Reply
    • mike

      Dan, did you just blame medical junk science on "liberals"? LOL...blame the "libs" for everything! They're all out to get you! Do you also blame liberals when your socks go missing?

      The ironic part of you comment is that it's usually the right wing that embraces this kind of junk science (see: creationism, global warming denial, etc.).

      March 5, 2014 at 18:36 | Report abuse |
    • E.J.Dowd

      That's great re your grandpa. But really...what the ^&*( does this have to do with politics? That's an absurd stretch.

      March 5, 2014 at 19:28 | Report abuse |
  30. lean6

    Blah, blah, blah, blah, blah, blah, blah, blah and blah. Every couple of days at least, there's another article telling us what's going to kill us. I'm starting to actually think there's a campaign to desensitize people to unhealthy eating. If they tell you that dam near everything will kill you, at some point you'll start believing that you may as well super size it and ask for extra gravy.

    March 5, 2014 at 17:37 | Report abuse | Reply
  31. VEW2012

    Probably after a certain age one would be better off going somewhat vegetarian, and keep some protein in the form of nuts, beans, peas, milk, yogurt, cheese, and eggs, and limit meat to maybe twice a week such as fish, shellfish, and poultry. I have a friend who will be 100 in a couple of months and she has been a vegetarian for the largest portion of her life.....and she still drives.

    March 5, 2014 at 17:50 | Report abuse | Reply
  32. RonFromNM

    Quack alert. I'm 52, eat paleo style and crossfit and have never been in better shape in my life. This article is a steaming pile.

    March 5, 2014 at 17:51 | Report abuse | Reply
    • mike

      The article is definitely a steaming pile of faux-science, but the jury is still out on paleo and crossfit. Being "fit" in athletic terms doesn't necessarily mean you'll live longer. Totally different context. In fact, if you do crossfit, you may well be doing long term damage to your body. Just sayin'.

      March 5, 2014 at 18:38 | Report abuse |
    • Really?

      cross-fit is the stupidest, cliquesh, and most high-impact and injury causing form of exercise there is.

      March 5, 2014 at 19:54 | Report abuse |
  33. Doug

    "Middle-aged? Put down the meat"

    Yes. Nope.

    March 5, 2014 at 17:52 | Report abuse | Reply
  34. gager

    The report is nonsense. It is a big freiken lie. Carbs are the people killer and especially wheat.

    March 5, 2014 at 17:55 | Report abuse | Reply
  35. me

    This wasn't an issue until Obama got in office and screwed us all with Obamacare... no knuckle dragging, god fearing, gun toting right winger ever gives up their right to animal flesh... your card is revoked if you dare to suggest you are a veghead! You'll have to pry that bloody rare t-bone from my cold dead hands... right Dan, you seem to know who the tough guys are... your labels make them liberals weak... many like you probably eats them for breakfast, in fact I'm sure you're a man's man (don't worry I'll keep it on the d/l for you... see you in the bathroom stall stud)

    March 5, 2014 at 17:56 | Report abuse | Reply
  36. b

    This has been known for decades.

    March 5, 2014 at 18:08 | Report abuse | Reply
  37. Jason Young Guy

    Being 41 and weighing around 134, I eat well but have a high metabolism which I contribute to my small size or weight. I think we don't have to give up our favorite foods like a big Prime Rib for me, as long as, most eat with moderation. Over indulgence of meats or any type of food can increase the risk of diabetes and obesity, thus as we see today.

    I think with good moderation of eating, and not necessarily having to eat three meals a day, is the key to good health and prevention. Plan out how many times you eat red meat, vegetables, deserts, and fiber in a week, and go from there in setting a target goal.

    I'd say most importantly, set a limit or goal for each meal whether it cures the hunger craving or not. Your body will survive with sufficient food amounts even though your hunger cravings says different. In my opinion, and I've done pretty well.

    However, do listen to the experts and your doctor, this was only my opinion and as to how I think obesity and diabetes can be addressed based on my personal habits and observations of others and food. Moderation of anything is a good thing.

    March 5, 2014 at 18:13 | Report abuse | Reply
  38. PHinMiami

    Killing animals is just bad Karma

    March 5, 2014 at 18:13 | Report abuse | Reply
  39. Primal 4 Life

    LMAO totally flawed study with absolutely zero merit. So many factors unaccounted for. Plus they still ate grains and dairy which are far more likely to be the true cause.

    I'll keep eating the way I eat now. I am perfectly healthy have have the doctors tests to prove it.

    March 5, 2014 at 18:21 | Report abuse | Reply
  40. Big_D

    I still like the 90 year old iron man. He says just don't eat anything you can't identify the parts.

    March 5, 2014 at 18:29 | Report abuse | Reply
  41. mike

    Oh look, another medical "study" that treats correlative relationships as causal without any further examination. Why does the medical community get away with this sort of continual junk science? This is why so many people don't trust doctors. The profession has never truly emerged from the days of snake oil.

    March 5, 2014 at 18:32 | Report abuse | Reply
  42. mickinmd

    The wise Harvard Medical School Guide to Healthy Eating says that articles like these should be labeled "Preliminary Data Pending Further Investigation."

    March 5, 2014 at 18:36 | Report abuse | Reply
  43. gtbdave

    Generally, food is poisonous to us. If I emptied the house of all the things that I'm not supposed to eat, according to some, I would have no food in the house, nothing to drink either. Can't even drink the water. Just eat out side, eat the same stuff as the other animals, nuts, twigs, grass, bugs, etc.

    March 5, 2014 at 18:40 | Report abuse | Reply
  44. Al

    I think Michael Polan's advice is solid. He advises " eat food , not too much, mostly Plants." What he means by "food", is what your grandmother would recognize as food.

    March 5, 2014 at 18:40 | Report abuse | Reply
  45. Cathoryn

    Meat bad for 50 – 65 YOs, but not after 65 – sounds like correlation without causation to me.

    March 5, 2014 at 18:44 | Report abuse | Reply
  46. Pat Henry

    It's not how long you live, but how well. Supper tonight at Ruth Chris.

    March 5, 2014 at 18:53 | Report abuse | Reply
  47. mariosphere

    Put down the meat? You're crazy! First you'll have to pry the meat from my cold, middle-aged hands.

    March 5, 2014 at 18:59 | Report abuse | Reply
    • JeffinIL

      Great minds or something.

      March 5, 2014 at 19:02 | Report abuse |
  48. JeffinIL

    You can have my meat when you scrape it from my cold, dead, clogged arteries.

    March 5, 2014 at 19:01 | Report abuse | Reply
  49. Balls of Steel

    Middle-aged? Put down the meat. Wait what?

    March 5, 2014 at 19:14 | Report abuse | Reply
  50. Chris

    Peoples bodies change over time and their dietary needs change. I'm 50, and I stopped eating meat 2 1/2 years ago because of digestive issues. I see people that continue to eat like teenagers well into their 50's and they have not aged well at all. As for protein intake, I eat lots of nuts and other high protein vegetables, but I've found that it isn't as important as I used to think. I'm in the gym twice a week and the weights I work with have just increased over the past two years. I also love to mountain bike and I have tons of energy when I'm cranking through the trails, often blowing by people a lot younger than I am. And after going a while without meat, it kind of grosses me out to think about eating it. I keep picturing road kill.

    March 5, 2014 at 19:17 | Report abuse | Reply
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