My wife and I are almost 10 years into our n=2 study of eating a high-fat, low-carbohydrate lifestyle. The major changes made were to eliminate sugar as much as possible, stop consuming seed oils, and go for full-fat instead of low-fat whenever possible. Lots of grass-fed beef as well. We fall exactly into the age range of this study. At 77 and 78 we are the healthiest we've ever been. However it's not all about the diet. Every morning we walk 5k (3.1 miles) before doing anything else. We have none of the usual problems of old people, and have only one prescription between us for blood pressure. In the ages between 39 and 69 we were raising 3 kids, operating our own businesses, and eating the "Standard American Diet" with all its processed food miseries. If you make it to 70, it's not too late to fix the damage done.
Jim, you may, in addition to be smart and mindful about your diet and exercise and attention to consistency, also have damned good genes. I've read that getting to one's 70s is mostly environmental and lifestyle, influenced by genes only 10-25%; but after that, genes become hugely influential on the likelihood of becoming a super-ager.
Seed oils...I need to research why they're not advisable.
The problem with seed oils is their inherent chemical instability. This is worst when they are heated, and most are sold as cooking oils. They break down to release toxins. For a full rundown see these non DrCate.com: https://drcate.com/?s=seed+oils
Yup that’s pretty much my diet. Moved to butter and ghee and full fat decades ago. My weight never changes. It’s unnerving to continually hear saturated fat harms vessels and heart but so far so good.
A small recommendation, instead of walking the 5k try adding in some light jogging with the goal of eventually running the entire distance. This will increase the dilation and pliability of the blood vessels which will eliminate the need for the high blood pressure meds over time. I am close to your age and my blood pressure baseline is 105/63.
Rayzor, if running beats walking for blood vessel pliability, wouldn't HIIT sprints help even more? Every time I do them, I feel my body age backwards a few weeks...
Keep on truckin', Rayzor. When I run, it's usually in street clothes because I'm late picking up my daughter from school. And then the occasional HIIT sprints on the beach, which do a remarkably good job of showing me how unbalanced my core muscles are.
HIIT is very beneficial and can be easily sandwiched into a busy schedule. In fact, I do them at the end of my daily runs about three times a week. They specifically work fast twitch muscle fibers whereas long distance aerobic running helps to build stamina and VO2 max which is a prime marker of longevity along with grip strength. The reason you and I feel so much younger is the healthy release of dopamine into our bodies which acts as a natural antidepressant. It also helps with adrenal fatigue.
Running is not always an option if you have some sort of alignment issues or knee issues. As you mentioned, walking faster might be a good compromise that could work. Or adding a brief cardio HIIT exercise that works for your body which can be done on an exercise machine (bike or maybe stepper of some sort).
In my 40s I did run a couple of miles each day. I’d considered resuming that until I read Mark Sisson’s latest book “Born to Walk”. Following his recommendations, we’ll stick to walking. Running could lead to falling, which my wife has done twice, breaking a wrist each time. We’re working on dealing with osteoporosis, another gift from the old-age fairies.
Mark is a contemporary of mine, though much more talented than me. Many of us ran too hard for too many miles and burnout was the result. However, I never lost my love of the sport and ran a marathon and ultramarathon as little as 4 years ago. Probably a difference is I ran my way into old age and avoided most of the balance problems along with osteoporosis and osteoarthritis. One major change I implemented several years ago was increasing my protein intake dramatically from my younger years and avoiding the same things you and your wife do. But kudos to you both. You’re on the right track. So many people are broken physically.
That's interesting and not the first time I've heard people extoll the merits of high-fat, low-carb diets. Honest question: why do you like "fatty beef" so much, and what cuts qualify as fatty?
If you eat just meat, honey, dairy, nuts for awhile you lose weight and your energy levels go way up. And of the meats beef seems to be best. You end up eating less and feeling the need to snack less.
I think you might be misunderstanding the study’s findings. These people were born in or around 1947, so the relevant life expectancy measure is life expectancy at birth (LEB) in 1947. Using 2020 LEB measures is comparing apples to oranges, becuase the study participants were not born in 2020. The LEB for people born in 1947 in the US is approx. 65 and 70 years for men and women respectively. So a priori it is unsurprising that a majority of the study’s participants passed away before their 70th birthday.
Similarly, you need to interpret the healthy aging results conditional on having survived to the end of the study. For example, it is not accurate to claim that “two-thirds did not retain full cognitive function”—a majority of those two-thirds did not retain any cognitive function whatsoever because they were dead (again, as reasonably expected in accordance with relevant LEB measures). In reality, 89% of those who lived to the end of the study retained full cognitive function. The same applies to retaining intact physical function (74% did), being free of chronic diseases (60%) and maintaining intact mental health (70%).
Tomás, thank you for this. You're right about my incorrect inference of the percentages of cognitive function, eg. I corrected them to align directly with the study's results. Also, I've reached out to the lead researcher to ask similar questions about life expectancy, which can be calculated using cohort or period methods, which offer differing expectancies for this group of study subjects. I had wondered, too, whether the lack of healthy aging in one category overlaps into another, as you suggest. If my post is inaccurate, I will correct ASAP. Stay tuned.
Matjaž, I would think so, yes. For other readers' edification: Life expectancy is calculated using a tool called a life table, which shows, for each age, what the probability is that a person will die before his or her next birthday.
There are two different types of life table: cohort and period. The cohort life table takes into account observed and projected improvements in mortality for the cohort throughout its lifetime. Cohort figures are therefore regarded as a more appropriate measure of how long a person of a given age would be expected to live on average than the alternative measure, known as period life expectancy.
Period life expectancies use mortality rates from a single year (or group of years) and assume that those rates apply throughout the remainder of a person's life. This means that any future changes to mortality rates would not be taken into account.
I really appreciate your openness to the points made above. It makes me want to follow your work… Gives you greater credibility, in my mind at least. I have little experience and no expertise in the topics you are discussing. But I am interested. And I think that trusting a source is very important, especially for an uninformed person like myself. Your openness to critique makes you trustworthy imho. Thanks!
Steve, thanks for the vote of confidence. I think it's incredibly important, for the credibility that you rightly mention, to stay open to what I didn't get exactly right, or got very wrong. I hope those mistakes are a few and far between, but journalists who can't own up to ever making errors are the ones you end up not trusting very much. And this is a community we are building here, so trust is paramount. Please keep reading and holding me accountable!
By the way, is beer really that much worse than wine? Could it be that people who are already more health-conscious to begin with have heard that a bit of wine can be good for them while beer drinkers aren’t that health-conscious in general for whatever reason? I don’t know.
The study is observational; the results don’t indicate a cause-and-effect relationship but only associative ones: x behavior is associated to (but not necessarily causes, or is caused by) y outcome. That said, it could be that those folks who drink wine tended to do so with food and those that drank more beer didn't. Or that socioeconomic status (what the researchers abbreviated in their report as "SES") played a role — not surprisingly, if so — in who lives longer and not.
Amy, they are, indeed. Tomás and Matjaž each raised critical questions that I hope to answer in a follow-up interview with the author(s) of this research. So thankful for such smart and engaged AGING with STRENGTH readers!
As a fellow 70 yo “health professional” myself, I just knew the hidden nutritional joy of PIZZA 🍕 would someday be given its rightful due! We eat like shit in the hospital, but hey…
The effects of high fat in your diet is strongly correlated with carbohydrate intake. High to normal carb consumption will mean the fat is not utilised healthily. Low to very low carb consumption will digest and utilise full fat dairy much more easily, provided there is no intolerance. This study as shown here may be relevant to those that follow old standard advice and for a cohort that consumed ever increasing proportions of carbohydrates. I suspect much of the increase in life expectancy is down to the options and cultural acceptance of bespoke rather than standard diets. Of course the studies findings are not irrelevant, but this is a wickedly complex issue. Hopefully we’ll keep getting better at it, particularly with more people monitoring their diets closely with new technologies.
Wasiur, thank you. There's so much cynicism, much of it deserved, about journalism and the inability to take criticism these days, and I find that the only way to build a meaningful audience is to be as thorough as possible in my reporting and as transparent as possible owning up to any shortcomings in it. And then addressing them. We all make mistakes; it's how we handle them that matters so much.
I’m surprised by the low percentage surviving to 70. Maybe working now in the health professions is inherently unhealthy. I would argue it is, for all sorts of reasons!
This study is certainly impressive in scope and dataset longevity, but I think we need to be much more cautious about what kinds of causal or behavioral claims can be drawn from this kind of research. The use of questionnaires introduces profound limitations — not just measurement noise, but systematic reporting bias, especially among health professionals who are more likely to overreport “good” behavior and underreport less favorable habits. Moreover, the study does not meaningfully contend with social determinants of health, even though these are inseparable from both dietary behavior and health outcomes.
We also need to reckon with what GLP-1 receptor agonists (Ozempic etc. . ) have exposed about nutritional research. For decades, we blamed the failure of diet interventions on the interventions themselves — “they just don’t work.” But GLP-1s don’t fundamentally alter metabolism. What they do is modulate appetite and behavior: suddenly, highly palatable foods are no longer rewarding, people stop eating as much, and weight drops dramatically (and many risk factors for chronic disease/poor aging). The same people who “couldn’t” follow diets now do so consistently, without effort. The missing link wasn’t metabolic—it was behavioral fidelity, and that calls the validity of decades of dietary self-report studies into question.
I don’t doubt that diet matters, but I do doubt people's ability to self-report and the causal associations that can be drawn from that data.
Myka, thank you. Excellent points. I hope to ask the study's authors about the self-reporting bias. This study is observational, so there are no causal claims being made, only associations between certain dietary regimes and healthy aging, as defined by the study. I admit, I don't quite follow your point about what GLP-1s reveal about nutritional research. How does that cast doubt on studies that had relied on self-reporting?
Thank you! And yes—really looking forward to your conversation with the study authors. I’d love to hear how they think about the self-reporting issue because I think it’s more central than often acknowledged.
Just to clarify the GLP-1 point: I’m not suggesting that people were deliberately misleading researchers in self-reported diet studies. Rather, I’m pointing to a structural flaw in nutritional research—namely, that eating is often mindless, socially cued, and under-reported, even among highly health-literate people like healthcare workers.
For decades, when calorie-restricted diets “failed,” we assumed this was due to biological resistance—metabolism slowed, hormones adapted, epigenetics kicked in. And of course, some of that is true--see Herman Pontzer's work. But then GLP-1s came along. These drugs don’t rev up metabolism—they just dampen the compulsive drive to eat. Suddenly, huge numbers of people who had “failed” on diets were losing weight—consistently, and in ways that tracked very closely with reduced caloric intake.
What changed wasn’t their biology—it was their behavioural adherence. The GLP-1s didn’t make metabolism more efficient; they made compliance effortless. And that shift helped expose how much of prior nutritional research may have been distorted by poor measurement of what people actually ate.
So when I say GLP-1s challenge nutritional research, I mean that they unmasked the noise in decades of self-report-driven studies. Many “non-responders” to dietary interventions weren’t biologically resistant—they just weren’t eating what they thought they were eating. And that has huge implications for how we interpret the associations in observational studies like this one.
It’s true that you should compensate for the much lower life expectancy around 1947, but even more relevant is that these people already survived into adulthood. This means their life expectancy is higher than at birth, and much closer to current life expectancy because a large part of life expectancy improvements are due to less child mortality. You can use tables like these to see how this works out in practice: https://www.cdc.gov/nchs/data/hus/2017/015.pdf. The people in this study seem to be dying (very) early compared to their cohort, this could partly be caused by nightshifts in addition to the causes named in the paper.
Thank you, that's helpful to better understand. And the cdc link is, as well. I think I could spend a week learning about life expectancies and still have more questions than answers.
Amy, the authors offered an explanation for the fast fried foods being slightly green: they think it may indicate a tendency to socialize over meals (ie, going out for a burger with friends) which is associated with greater longevity vs eating alone. Community is a huge factor in life expectancy, of course. I imagine pizza may fall into the same explanation. But I hadn't realized Harvard has a red-meat bias. Does it also hate chickens and fish?
Interesting hypothesis about fast food. Do they have evidence? Is the community-protective effect larger when eating fast food than when enjoying steak together?
I don't know about Harvard's beliefs about chicken and fish. Although most of the diet folks seem to think fish is great and red meat is from the devil. So.
Diet is complex and multi-factorial, as everyone knows. Masai in Africa live quite well and long on red meat and fresh milk. Yet somehow here in America it is awful. Maybe it's not the meat. Maybe it's something else we eat or that's in our environment.
Agreed on complex. We each need to make a dietary plan that fits our schedules, budgets, health goals and taste buds. I've cut way back on red meat, though I do enjoy a fine filet now and then.
I’m in the meat world, feedlot specifically. I think that there’s a world of difference between steak and, say, store-bought ground beef. I think there’s a world of difference between ground beef from a steer that I would have slaughtered and put on my freezer and the ground beef in yet store that is a lot of old cows and bulls and added fat to make a certain percentage.
I don’t have any data for this, but it makes sense. Red meat is healthy if consumed in reasonable portions. The 12-16 oz ribeye in one sitting is probably an indicator of some other health issues. You are indeed correct about Harvard’s red meat bias.
You may be right. I mean, in California, people gather at In-N-Out. But not really at Murder King, McMurder or Murder in the Box. (Props to the spoken word poet in Chicago in 1991 who I just borrowed a humorous riff from...entirely from memory!)
Yes, but the Fig. 4 doesn't show a slight green for Fast Food. Each of the five domains are super green, greener than most of the healthy foods. I think that's a misprint that should be at least acknowledged by the authors.
The biggest thing I wonder after reading this is if any studies have been done comparing lifespans of health care professionals with people in the general population or in other careers. Do we have any data checking if they usually live longer or shorter? It seems like a question someone should have looked into before now!
There are quite a few unique aspects to working in Healthcare. They get pushed to take far more vaccines than the average person regardless of whether the particular vaccine is associated with better outcomes for their individual health situation. They tend to be more resistant to natural health therapies because their field biases them against those. And of course there is stress and traumatic experiences in working with very sick or injured people. Some have night shifts and others avoid them, but probably a large number have worked nights at some point in their career. So there are these risk factors, but they are also educated, which is associated with many good habits and outcomes.
Shelle, thank you. It's an interesting, ongoing question. You're not the first to raise it, though not in this specific way. For many of the causes you allude to, it would seem plausible that health professionals would have a more difficult time aging with health (however one defines that notion.) In my follow-up interview with this study's lead researcher, I asked whether this specific cohort would have been expected to have better-than-average health. https://agingwithstrength.substack.com/p/q-and-a-harvards-healthy-aging-lead?r=88kaf
This article and its comments are very good. An addition: here’s what jumped out for me–fish and seafood are neutral or mildly associated with harm. What??!
Amelia, I agree. These are associated and not directly correlated results, which can explain some apparent mysteries or contradictions in the data, including the mild association of healthy aging with eating fast food, which the researchers theorized was due to the positive impact of strong social networks which would foster occasions to go eat burgers out of the house, etc.
So if you eat fish and poultry as part of a healthy diet and move your body regularly, you are doing very well, any expert would likely say. Keep going!
I work on 75% healthy foods and 25% non healthy but taste nice are treats and my wife likes to bake. I exercise if not daily then close to it. Today is4k row and 45 mins lite weights. I don't smoke. Drink in moderation occasionally. Avoid sugar in tea. Don't but salt in cooking. Steam veg never boil them. Keep mentally active. Started PhD at 59. Had R Hip resurfaced last autumn but getting back into it. Just move. Be active. Do moderation. Stroke furry animals. Soend time in nature. Spend time alone.
One thought on the vegetable -> chronic disease relationship... Personally, I switched to vegetarian diet as a result of chronic disease onset. Many folks I know have similar GI issues.
One thing and it might have been covered off - average life span includes all those who died young. If you are a health care professional you already eliminated all the high risk young years. What is the lifespan of someone who is already 40? Likely higher than 78.
I belief cohort life expectancy takes that consideration into account, whereas period life expectancy (I explain both of these in a footnote in the post itself) does not. Needless to say, life expectancy is a complicated subject. Which is why life insurance companies spend so much money determining how long each of us will live…with remarkable accuracy. I had asked a life-expectancy question of the lead researchers, but she didn’t address it directly.
My wife and I are almost 10 years into our n=2 study of eating a high-fat, low-carbohydrate lifestyle. The major changes made were to eliminate sugar as much as possible, stop consuming seed oils, and go for full-fat instead of low-fat whenever possible. Lots of grass-fed beef as well. We fall exactly into the age range of this study. At 77 and 78 we are the healthiest we've ever been. However it's not all about the diet. Every morning we walk 5k (3.1 miles) before doing anything else. We have none of the usual problems of old people, and have only one prescription between us for blood pressure. In the ages between 39 and 69 we were raising 3 kids, operating our own businesses, and eating the "Standard American Diet" with all its processed food miseries. If you make it to 70, it's not too late to fix the damage done.
Jim, you may, in addition to be smart and mindful about your diet and exercise and attention to consistency, also have damned good genes. I've read that getting to one's 70s is mostly environmental and lifestyle, influenced by genes only 10-25%; but after that, genes become hugely influential on the likelihood of becoming a super-ager.
Seed oils...I need to research why they're not advisable.
The problem with seed oils is their inherent chemical instability. This is worst when they are heated, and most are sold as cooking oils. They break down to release toxins. For a full rundown see these non DrCate.com: https://drcate.com/?s=seed+oils
Thanks, Jim!
Easy to replace them when preparing your own meals. Difficult if eating out!
Yup that’s pretty much my diet. Moved to butter and ghee and full fat decades ago. My weight never changes. It’s unnerving to continually hear saturated fat harms vessels and heart but so far so good.
A small recommendation, instead of walking the 5k try adding in some light jogging with the goal of eventually running the entire distance. This will increase the dilation and pliability of the blood vessels which will eliminate the need for the high blood pressure meds over time. I am close to your age and my blood pressure baseline is 105/63.
Rayzor, if running beats walking for blood vessel pliability, wouldn't HIIT sprints help even more? Every time I do them, I feel my body age backwards a few weeks...
I’m 68 and a runner for 46 years. Time indeed does fly.
Keep on truckin', Rayzor. When I run, it's usually in street clothes because I'm late picking up my daughter from school. And then the occasional HIIT sprints on the beach, which do a remarkably good job of showing me how unbalanced my core muscles are.
HIIT is very beneficial and can be easily sandwiched into a busy schedule. In fact, I do them at the end of my daily runs about three times a week. They specifically work fast twitch muscle fibers whereas long distance aerobic running helps to build stamina and VO2 max which is a prime marker of longevity along with grip strength. The reason you and I feel so much younger is the healthy release of dopamine into our bodies which acts as a natural antidepressant. It also helps with adrenal fatigue.
Interesting. If you don't mind me asking, how old are you?
Running is not always an option if you have some sort of alignment issues or knee issues. As you mentioned, walking faster might be a good compromise that could work. Or adding a brief cardio HIIT exercise that works for your body which can be done on an exercise machine (bike or maybe stepper of some sort).
In my 40s I did run a couple of miles each day. I’d considered resuming that until I read Mark Sisson’s latest book “Born to Walk”. Following his recommendations, we’ll stick to walking. Running could lead to falling, which my wife has done twice, breaking a wrist each time. We’re working on dealing with osteoporosis, another gift from the old-age fairies.
Jim, do you each do some resistance training, for bone health?
Increasing your walking speed one minute
Mark is a contemporary of mine, though much more talented than me. Many of us ran too hard for too many miles and burnout was the result. However, I never lost my love of the sport and ran a marathon and ultramarathon as little as 4 years ago. Probably a difference is I ran my way into old age and avoided most of the balance problems along with osteoporosis and osteoarthritis. One major change I implemented several years ago was increasing my protein intake dramatically from my younger years and avoiding the same things you and your wife do. But kudos to you both. You’re on the right track. So many people are broken physically.
n apparently did not include many ketovore/carnivore eaters.
And now I have to go reread Ancel Keyes (sob), because upon reflection, the table results are looking suspiciously similar.
Everyone I know that eats low carb high fat, high protein feels great. Tons of energy. The more fatty beef the better.
That's interesting and not the first time I've heard people extoll the merits of high-fat, low-carb diets. Honest question: why do you like "fatty beef" so much, and what cuts qualify as fatty?
Rib Eyes. Chucks. New York.
If you eat just meat, honey, dairy, nuts for awhile you lose weight and your energy levels go way up. And of the meats beef seems to be best. You end up eating less and feeling the need to snack less.
And salt. All the things they told you not to eat.
I think you might be misunderstanding the study’s findings. These people were born in or around 1947, so the relevant life expectancy measure is life expectancy at birth (LEB) in 1947. Using 2020 LEB measures is comparing apples to oranges, becuase the study participants were not born in 2020. The LEB for people born in 1947 in the US is approx. 65 and 70 years for men and women respectively. So a priori it is unsurprising that a majority of the study’s participants passed away before their 70th birthday.
Similarly, you need to interpret the healthy aging results conditional on having survived to the end of the study. For example, it is not accurate to claim that “two-thirds did not retain full cognitive function”—a majority of those two-thirds did not retain any cognitive function whatsoever because they were dead (again, as reasonably expected in accordance with relevant LEB measures). In reality, 89% of those who lived to the end of the study retained full cognitive function. The same applies to retaining intact physical function (74% did), being free of chronic diseases (60%) and maintaining intact mental health (70%).
Tomás, thank you for this. You're right about my incorrect inference of the percentages of cognitive function, eg. I corrected them to align directly with the study's results. Also, I've reached out to the lead researcher to ask similar questions about life expectancy, which can be calculated using cohort or period methods, which offer differing expectancies for this group of study subjects. I had wondered, too, whether the lack of healthy aging in one category overlaps into another, as you suggest. If my post is inaccurate, I will correct ASAP. Stay tuned.
Isn’t cohort life expectancy more relevant here? I think that’s 73 and 78.7 for 1947 (for the US.) https://www.ssa.gov/oact/TR/2012/lr5a4.html
Matjaž, I would think so, yes. For other readers' edification: Life expectancy is calculated using a tool called a life table, which shows, for each age, what the probability is that a person will die before his or her next birthday.
There are two different types of life table: cohort and period. The cohort life table takes into account observed and projected improvements in mortality for the cohort throughout its lifetime. Cohort figures are therefore regarded as a more appropriate measure of how long a person of a given age would be expected to live on average than the alternative measure, known as period life expectancy.
Period life expectancies use mortality rates from a single year (or group of years) and assume that those rates apply throughout the remainder of a person's life. This means that any future changes to mortality rates would not be taken into account.
https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/lifeexpectancies/methodologies/periodandcohortlifeexpectancyexplained
Great conversation because all parties read critically, interrogating data carefully before stating findings. Refreshing.
Maurine, refreshing and encouraging, indeed. Thanks for reading.
I really appreciate your openness to the points made above. It makes me want to follow your work… Gives you greater credibility, in my mind at least. I have little experience and no expertise in the topics you are discussing. But I am interested. And I think that trusting a source is very important, especially for an uninformed person like myself. Your openness to critique makes you trustworthy imho. Thanks!
Steve, thanks for the vote of confidence. I think it's incredibly important, for the credibility that you rightly mention, to stay open to what I didn't get exactly right, or got very wrong. I hope those mistakes are a few and far between, but journalists who can't own up to ever making errors are the ones you end up not trusting very much. And this is a community we are building here, so trust is paramount. Please keep reading and holding me accountable!
By the way, is beer really that much worse than wine? Could it be that people who are already more health-conscious to begin with have heard that a bit of wine can be good for them while beer drinkers aren’t that health-conscious in general for whatever reason? I don’t know.
The study is observational; the results don’t indicate a cause-and-effect relationship but only associative ones: x behavior is associated to (but not necessarily causes, or is caused by) y outcome. That said, it could be that those folks who drink wine tended to do so with food and those that drank more beer didn't. Or that socioeconomic status (what the researchers abbreviated in their report as "SES") played a role — not surprisingly, if so — in who lives longer and not.
Well beer generally has more sugar in it than wine.
And there appeared to be a trend on that chart with sugar being bad for you (unsurprisingly).
Possible explanation.
Good points!
Amy, they are, indeed. Tomás and Matjaž each raised critical questions that I hope to answer in a follow-up interview with the author(s) of this research. So thankful for such smart and engaged AGING with STRENGTH readers!
Yikes, valid critiques
As a fellow 70 yo “health professional” myself, I just knew the hidden nutritional joy of PIZZA 🍕 would someday be given its rightful due! We eat like shit in the hospital, but hey…
Gordon, you have been vindicated.
The effects of high fat in your diet is strongly correlated with carbohydrate intake. High to normal carb consumption will mean the fat is not utilised healthily. Low to very low carb consumption will digest and utilise full fat dairy much more easily, provided there is no intolerance. This study as shown here may be relevant to those that follow old standard advice and for a cohort that consumed ever increasing proportions of carbohydrates. I suspect much of the increase in life expectancy is down to the options and cultural acceptance of bespoke rather than standard diets. Of course the studies findings are not irrelevant, but this is a wickedly complex issue. Hopefully we’ll keep getting better at it, particularly with more people monitoring their diets closely with new technologies.
Thanks for reporting on this and being so open with the discussions in the comments section. Truly refreshing to read and reflect.
Wasiur, thank you. There's so much cynicism, much of it deserved, about journalism and the inability to take criticism these days, and I find that the only way to build a meaningful audience is to be as thorough as possible in my reporting and as transparent as possible owning up to any shortcomings in it. And then addressing them. We all make mistakes; it's how we handle them that matters so much.
“aged 39 to 69”
So I’m officially entering midlife in less than two months?
Oh s**t. I wasn’t ready for this.
It's not as bad as it was 20 years ago. And, these days, midlife can easily last 20 years.
I’m surprised by the low percentage surviving to 70. Maybe working now in the health professions is inherently unhealthy. I would argue it is, for all sorts of reasons!
That's what I had suspected, also—were health professionals less healthy than the rest of us?—but then I asked the study's lead author about that: https://agingwithstrength.substack.com/p/q-and-a-harvards-healthy-aging-lead?r=88kaf
This study is certainly impressive in scope and dataset longevity, but I think we need to be much more cautious about what kinds of causal or behavioral claims can be drawn from this kind of research. The use of questionnaires introduces profound limitations — not just measurement noise, but systematic reporting bias, especially among health professionals who are more likely to overreport “good” behavior and underreport less favorable habits. Moreover, the study does not meaningfully contend with social determinants of health, even though these are inseparable from both dietary behavior and health outcomes.
We also need to reckon with what GLP-1 receptor agonists (Ozempic etc. . ) have exposed about nutritional research. For decades, we blamed the failure of diet interventions on the interventions themselves — “they just don’t work.” But GLP-1s don’t fundamentally alter metabolism. What they do is modulate appetite and behavior: suddenly, highly palatable foods are no longer rewarding, people stop eating as much, and weight drops dramatically (and many risk factors for chronic disease/poor aging). The same people who “couldn’t” follow diets now do so consistently, without effort. The missing link wasn’t metabolic—it was behavioral fidelity, and that calls the validity of decades of dietary self-report studies into question.
I don’t doubt that diet matters, but I do doubt people's ability to self-report and the causal associations that can be drawn from that data.
Myka, thank you. Excellent points. I hope to ask the study's authors about the self-reporting bias. This study is observational, so there are no causal claims being made, only associations between certain dietary regimes and healthy aging, as defined by the study. I admit, I don't quite follow your point about what GLP-1s reveal about nutritional research. How does that cast doubt on studies that had relied on self-reporting?
Thank you! And yes—really looking forward to your conversation with the study authors. I’d love to hear how they think about the self-reporting issue because I think it’s more central than often acknowledged.
Just to clarify the GLP-1 point: I’m not suggesting that people were deliberately misleading researchers in self-reported diet studies. Rather, I’m pointing to a structural flaw in nutritional research—namely, that eating is often mindless, socially cued, and under-reported, even among highly health-literate people like healthcare workers.
For decades, when calorie-restricted diets “failed,” we assumed this was due to biological resistance—metabolism slowed, hormones adapted, epigenetics kicked in. And of course, some of that is true--see Herman Pontzer's work. But then GLP-1s came along. These drugs don’t rev up metabolism—they just dampen the compulsive drive to eat. Suddenly, huge numbers of people who had “failed” on diets were losing weight—consistently, and in ways that tracked very closely with reduced caloric intake.
What changed wasn’t their biology—it was their behavioural adherence. The GLP-1s didn’t make metabolism more efficient; they made compliance effortless. And that shift helped expose how much of prior nutritional research may have been distorted by poor measurement of what people actually ate.
So when I say GLP-1s challenge nutritional research, I mean that they unmasked the noise in decades of self-report-driven studies. Many “non-responders” to dietary interventions weren’t biologically resistant—they just weren’t eating what they thought they were eating. And that has huge implications for how we interpret the associations in observational studies like this one.
Thank you for the explanation. There is a lot to learn here.
I’m curious, did the study track whether the participants worked shift work?
Graham, I've asked that question to one of the co-authors. I'll let you and everyone know if I get an answer. Thanks.
It’s true that you should compensate for the much lower life expectancy around 1947, but even more relevant is that these people already survived into adulthood. This means their life expectancy is higher than at birth, and much closer to current life expectancy because a large part of life expectancy improvements are due to less child mortality. You can use tables like these to see how this works out in practice: https://www.cdc.gov/nchs/data/hus/2017/015.pdf. The people in this study seem to be dying (very) early compared to their cohort, this could partly be caused by nightshifts in addition to the causes named in the paper.
Thank you, that's helpful to better understand. And the cdc link is, as well. I think I could spend a week learning about life expectancies and still have more questions than answers.
So pizza and fast fried foods are better than unprocessed red meat? This seems a bit bizarre. Although Harvard has never liked red meat. So.
Amy, the authors offered an explanation for the fast fried foods being slightly green: they think it may indicate a tendency to socialize over meals (ie, going out for a burger with friends) which is associated with greater longevity vs eating alone. Community is a huge factor in life expectancy, of course. I imagine pizza may fall into the same explanation. But I hadn't realized Harvard has a red-meat bias. Does it also hate chickens and fish?
Interesting hypothesis about fast food. Do they have evidence? Is the community-protective effect larger when eating fast food than when enjoying steak together?
I don't know about Harvard's beliefs about chicken and fish. Although most of the diet folks seem to think fish is great and red meat is from the devil. So.
Diet is complex and multi-factorial, as everyone knows. Masai in Africa live quite well and long on red meat and fresh milk. Yet somehow here in America it is awful. Maybe it's not the meat. Maybe it's something else we eat or that's in our environment.
Agreed on complex. We each need to make a dietary plan that fits our schedules, budgets, health goals and taste buds. I've cut way back on red meat, though I do enjoy a fine filet now and then.
I’m in the meat world, feedlot specifically. I think that there’s a world of difference between steak and, say, store-bought ground beef. I think there’s a world of difference between ground beef from a steer that I would have slaughtered and put on my freezer and the ground beef in yet store that is a lot of old cows and bulls and added fat to make a certain percentage.
I don’t have any data for this, but it makes sense. Red meat is healthy if consumed in reasonable portions. The 12-16 oz ribeye in one sitting is probably an indicator of some other health issues. You are indeed correct about Harvard’s red meat bias.
I’m not sure that a lot of people are gathering around a table at Wendy’s. Most fast food is from a drive thru and many people eat alone.
How many people even bring fast food home to eat? They scarf it down in the car while on the way to going somewhere.
You may be right. I mean, in California, people gather at In-N-Out. But not really at Murder King, McMurder or Murder in the Box. (Props to the spoken word poet in Chicago in 1991 who I just borrowed a humorous riff from...entirely from memory!)
People gather for steaks too, at home. 😃
Yes, but the Fig. 4 doesn't show a slight green for Fast Food. Each of the five domains are super green, greener than most of the healthy foods. I think that's a misprint that should be at least acknowledged by the authors.
The biggest thing I wonder after reading this is if any studies have been done comparing lifespans of health care professionals with people in the general population or in other careers. Do we have any data checking if they usually live longer or shorter? It seems like a question someone should have looked into before now!
There are quite a few unique aspects to working in Healthcare. They get pushed to take far more vaccines than the average person regardless of whether the particular vaccine is associated with better outcomes for their individual health situation. They tend to be more resistant to natural health therapies because their field biases them against those. And of course there is stress and traumatic experiences in working with very sick or injured people. Some have night shifts and others avoid them, but probably a large number have worked nights at some point in their career. So there are these risk factors, but they are also educated, which is associated with many good habits and outcomes.
Shelle, thank you. It's an interesting, ongoing question. You're not the first to raise it, though not in this specific way. For many of the causes you allude to, it would seem plausible that health professionals would have a more difficult time aging with health (however one defines that notion.) In my follow-up interview with this study's lead researcher, I asked whether this specific cohort would have been expected to have better-than-average health. https://agingwithstrength.substack.com/p/q-and-a-harvards-healthy-aging-lead?r=88kaf
This article and its comments are very good. An addition: here’s what jumped out for me–fish and seafood are neutral or mildly associated with harm. What??!
Amelia, I agree. These are associated and not directly correlated results, which can explain some apparent mysteries or contradictions in the data, including the mild association of healthy aging with eating fast food, which the researchers theorized was due to the positive impact of strong social networks which would foster occasions to go eat burgers out of the house, etc.
So if you eat fish and poultry as part of a healthy diet and move your body regularly, you are doing very well, any expert would likely say. Keep going!
I work on 75% healthy foods and 25% non healthy but taste nice are treats and my wife likes to bake. I exercise if not daily then close to it. Today is4k row and 45 mins lite weights. I don't smoke. Drink in moderation occasionally. Avoid sugar in tea. Don't but salt in cooking. Steam veg never boil them. Keep mentally active. Started PhD at 59. Had R Hip resurfaced last autumn but getting back into it. Just move. Be active. Do moderation. Stroke furry animals. Soend time in nature. Spend time alone.
Sounds like pretty good advice to me.
One thought on the vegetable -> chronic disease relationship... Personally, I switched to vegetarian diet as a result of chronic disease onset. Many folks I know have similar GI issues.
One thing and it might have been covered off - average life span includes all those who died young. If you are a health care professional you already eliminated all the high risk young years. What is the lifespan of someone who is already 40? Likely higher than 78.
I belief cohort life expectancy takes that consideration into account, whereas period life expectancy (I explain both of these in a footnote in the post itself) does not. Needless to say, life expectancy is a complicated subject. Which is why life insurance companies spend so much money determining how long each of us will live…with remarkable accuracy. I had asked a life-expectancy question of the lead researchers, but she didn’t address it directly.