Harvard Study: Planetary Health Index Diet – lower mortality and 30% lower CO2
sciencedirect.comIt looks like they asked (a large number of) participants what they eat, and checked a correlation between their health and how closely they follow their Planetary Health Diet[1].
First, I don't see any attempt to control for the fact that people who eat "healthy" diets (vegetarian, vegan, avoid sugars and red meat, etc) are often the same people who care about exercise, do routine health checks etc. So even if the diet itself was a placebo, this mere correlation would show results as if it's helpful.
Second, It's already a known fact that avoiding too much red meat and sugar is good for you, so it's not surprising that a mostly vegetarian/vegan diet has health benefits compared to the average. I guess this study shows that this diet, which was designed for planet health, is also good for human health? It's a noble goal, but most people - maybe selfishly - primarily care about their own health. It would be interesting to quantify how much worse for health this diet is compared to a diet optimised for human health[2].
I also don't get the 30% lower CO2 part. Is it about CO2 generated by growing food/raising livestock? One doesn't need a study to know that eating mostly plants generates less CO2.
Disclaimer: I don't have access to the full paper so I've only studied the available abstract.
[1] Mostly vegan with some animal protein: https://eatforum.org/eat-lancet-commission/the-planetary-hea...
[2] Ideally it is (within an experimental error) as good as the "optimal" human diet, but it would be nice to hear that explicitly.
About your third point: raising animals on pastures is not necessarily worse regards climate compared to growing vegetables on fields. It may well be the other way around. For example: the humus layer is much deeper with grass, hence storing more CO2.
About your second point, you name it as "fact" that too much red meat is problematic. Scientists are not so sure if it is about the meat or about some side-effect, like e.g., a virus transmitted along with (rare/raw, or even higher heated) meat in Western societies. Reference: https://doi.org/10.1002/ijc.27413
> About your third point: raising animals on pastures is not necessarily worse regards climate compared to growing vegetables on fields.
Thermodynamics by itself would already question this assertion, no?
maybe. there is an emerging body of evidence showing that different grazing methods influence carbon sequestration rates. https://pastureproject.org/about-us/regenerative-grazing-ben... https://www.theguardian.com/environment/article/2024/may/15/...
>About your second point, you name it as "fact" that too much red meat is problematic.
Too much red meat is tautologically problematic, because too much of anything (including water) is problematic :). I'm not a dietician so I don't have opinion on this, but I was thinking mostly of a common western diet full of highly-processed, highly fat and overly salty meats.
It is not at all a "known fact" that "avoiding too much red meat" is "good for you". There has never been a single large-scale, long-term randomized controlled trial which has shown such causality.
In general there are hardly any "known facts" in biology, least of all in human nutrition. All we have are probabilities. Most human nutrition studies that relate to this issue have been observational and relied on subject-reported data: in other words, junk science.
If there is an actual signal here one way or the other then it certainly has a much smaller impact on overall human health than other factors like energy balance, exercise, sleep quality, chronic stress, etc. There's a lot of other stuff to optimize first before we even think about the relative quantities of plant/fungus versus animal foods in our diets.
What I would have liked to see and which should exist in the full paper, but it is not described in the summary or in the snippets, is the exact method used to compute the score for a given diet.
It is not possible to compute any kind of valid score for an aliment taken in isolation, because no aliment is healthy if one would eat only that.
The various aliments complement their contents of nutrients and a pair of certain aliments can be very healthy, even when eating only one in the absence of the other would be unhealthy.
Moreover the quantity of an aliment matters a lot. For small quantities, most aliments are neither healthy nor unhealthy, they do not provide any noticeable contribution, positive or negative. For medium quantities, an aliment can be healthy or unhealthy, depending on which are the other components of the diet. For large quantities, almost any aliment becomes unhealthy.
So computing a realistic score for a daily diet is quite difficult and just giving vague guidelines like eating "mostly" vegetables with "a little" animal protein, while correct is completely unhelpful for providing any quantitative conclusions.
I hope that the full paper includes a valid methodology for characterizing a diet, but I somewhat doubt this, because I have never seen such a precise methodology yet.
The first step for computing a score would be to have for each component of the daily diet both the daily intake and the array of values with its content for all of the about 50 essential nutrients that are required by a human to live. The content values should take into consideration the digestibility of that aliment by humans.
Then by multiplying the nutrient contents with the daily intakes, one would obtain an array of about 50 values with the daily intakes for each essential nutrient. For each nutrient there is an optimal range for the daily intake, and the values that are either higher or lower must be penalized the farther they are from the optimal range.
To this initial score, various correction factors must be applied. The food must require a certain amount of chewing effort, in order to preserve the health of the teeth. If that is not true a diet must be penalized. The food must contain some amount of indigestible fiber, to help the transit through the intestine. If that is not true a diet must be penalized. There are many vegetables or fruits for which there is decent evidence that they contain something that improves health, especially cardiovascular health, but it is unknown which are the exact substances with favorable effect and which is the mechanism that explains their action. A diet containing such vegetables or fruits should be scored better.
The diet:
> The food-based reference diet for generally healthy individuals aged ≥2 y emphasizes high consumption of high-quality plant-based foods (e.g., whole grains, vegetables, fruits, nuts and legumes, and unsaturated plant oils), low to moderate amounts of animal-sourced foods, and low intakes of saturated fats, refined grains, and sugar.
The only way I’ve found (that works for me) is avoiding regular grocery stores at all costs and only shopping at health food stores.
The same stores will have more brands of granola than they do brands of regular cereal. They most often don’t carry things like Oreos, and many won’t carry nation-wide brands at all. (You won’t find Heinz ketchup, for instance)
I find it extremely difficult to shop healthy at regular grocery stores where 90%+ of the items stocked are heavily manufactured and processed.
The downside to health food grocery stores is they’re out of reach for anyone other than upper class income since the food prices tend to be… insane.
Edit: insane as in the same can of soup at a health food store can easily be $6 while costing $3 at a regular grocery store for the same exact product.
My "trick" at regular grocery stores is to stick primarily to the perimeter: produce, dairy, meat. The only aisles I regularly go down are for spices, grains of some sort (typically rice), beans, and stocks (too lazy to make my own).
I've never had to bother with health food stores, though I guess it has the benefit of removing temptation. Whenever I've visited one, the prices made no sense to me for the things they were selling.
A better option to remove the temptation is some of the smaller grocery chains (Sprouts, Fresh Market). They have reliably had good produce and meat at reasonable prices (Fresh Market's meat and produce prices, when I lived near them, were reliably better than Kroger and Publix with better quality). Bulk items are a bit difficulty, Fresh Market sold rice at a terrible price so I'd still hit Kroger for that (the local one to me at the time had produce practically rotting on the shelf, spoiled by the next day if I ever bought any, but rice and dry beans are hard to screw up). Sprouts' rice and beans and lentils are priced reasonably, a bit high but not bad.
But the canned goods, chips, and other things at both of them are priced at twice what the regular groceries sell them for, and about 4x (or more) what Walmart has for the same items. Easy to walk past them and not spend that money.
> the same can of soup at a health food store can easily be $6 while costing $3 at a regular grocery
yes, maybe because the regular store can buy in much higher volume, and will have faster turnover of stock?
You can find real food at any grocery store. You just have to keep walking past the froot loops. You can buy a bag of lentils, some onions and carrots, some potatoes, some oranges anywhere.
I think the problem is I don’t have the self-control to just keep walking past those things!
Where are you located? Most grocery stores probably have at least frozen veggies and fruit and I assume some selection of fish/meat.
And btw granola really isn't that healthy.
Almost any diet that contains mostly real food rather than artificial food-like substances will produce substantial improvements in health. Contents are hugely secondary to actually consuming real food.
Only when factories focus on making addictive instead of healthy food. You can ruin the food yourself in the same way. Different cultures do this differently, so you see much healthier fast food packages in some countries than others.
Since we have food production mostly figured out and we don't need any new production optimizations do we really need food production to remain the domain of free market?
Maybe governments should set up production of healthy convenient packaged food and give it away for free. Then gradually ban businesses from selling the worst products.
Socialized food production inevitably leads to shortages and famines. Governments can't be trusted with something as important as food.
Technology advanced a ton since the last time it happened. And food making is no longer that lucrative. Other industries give more opportunities for corruption.
Besides, I don't advocate for nationalising entire food production. Just carving out small segment that by design operates at a loss because it acts altruistically not with market ruthlesness towards consumers.
It can be trusted as well/bad as for water, electricity, security…
It about quality food being vital for everybody, not about importance. A public “default food package“ could have a big impact for many families health. The private options can stay , regulated, as well as for water, electricity and safety.
Food isn’t all about macros, you need to get your micronutrients (minerals etc), which heavy processing partially removes. There’s also the rabbit hole of soil quality, where a plant can only contain the nutrients its soil has offered (copper, molybdenum, humic acid etc), where organic food tends to be better because soil health is actually looked at.
> which heavy processing partially removes
Only because they don't focus on micronutrients.
> where organic food tends to be better because soil health is actually looked at.
You don't think large scale farmers look at soil health? Every single large scale farmer knows about soil health.
> Agriculture and food production are responsible for ∼30% of greenhouse gas
The title seems a bit misleading
>Methods
>We followed 66,692 females from the Nurses’ Health Study (1986–2019), 92,438 females from the Nurses’ Health Study II (1989–2019), and 47,274 males from the Health Professionals Follow-up Study (1986–2018) who were free of cancer, diabetes, and major cardiovascular diseases at baseline. The PHDI was calculated every 4 y using a semiquantitative food frequency questionnaire.
Into the roundfile it goes!