The truth about vegan diets and lifespan, according to researchers

We all know someone who swears a plant-based plate is the passport to a longer life.

But is that actually true—or just good marketing with a side of kale? I dug into the research, looked past the hype, and pulled together what scientists are really finding about vegan diets and longevity.

Short version: a well-planned vegan or predominantly plant-based diet is associated with a lower risk of dying from major diseases.

But it’s not a magic shield, and the quality of your plant-based choices matters more than the label on your diet.

Let’s unpack the nuance.

What the biggest cohort studies actually show

One of the most robust snapshots we have comes from the Adventist Health Study-2 (AHS-2), a large North American cohort that includes many people who follow vegetarian and vegan diets.

Over roughly six years of follow-up, researchers found that people following vegetarian patterns had a lower risk of dying from any cause compared with meat-eaters.

In fact, the study reported that vegetarians, as a group, had about a 12% lower all-cause mortality risk after adjusting for age, lifestyle, and other factors.

As noted by the authors, “vegetarian dietary patterns [were] associated with reduced all-cause mortality,” and the benefit appeared somewhat stronger in men. (That’s me paraphrasing, but their findings are clear.)

If you’re a details person, AHS-2 didn’t lump all plant-forward eaters together.

Vegans, lacto-ovo vegetarians, and pesco-vegetarians (fish, no other meat) each showed favorable hazard ratios compared with nonvegetarians—again, after statistical adjustments.

The takeaway: moving along the plant-centric spectrum correlates with lower mortality risk in this well-studied community.

But it’s not “vegan = immortal”

Now for the nuance. The EPIC-Oxford cohort in the UK—another massive, long-running study—found that vegetarians and vegans had lower risk of ischemic heart disease but higher risk of certain types of stroke compared with meat-eaters.

That means the picture isn’t one-note. As the authors of a widely cited analysis put it, vegetarian diets showed lower ischemic heart disease risk, while “higher rates of haemorrhagic and total stroke were observed in vegetarians.”

Does that cancel out longevity benefits? Not necessarily. It does mean that “plant-based” isn’t a free pass; pattern and planning matter.

The quality of your plant-based diet matters most

Here’s where things get practical.

Recent systematic reviews and meta-analyses looking at plant-based patterns (not just labels) consistently suggest lower all-cause mortality when the diet emphasizes whole or minimally processed plants—think legumes, vegetables, fruit, whole grains, nuts, seeds.

One 2024 meta-analysis concluded that adherence to plant-based diets was associated with reduced risk of death from any cause (with the usual caveats about observational evidence).

That’s encouraging—and also a nudge to keep the focus on unprocessed plants rather than plant-based junk.

I like to imagine two lunch boxes labeled “vegan.” One has lentil salad, leafy greens, quinoa, and walnuts.

The other has ultra-processed nuggets, fries, and a soda. Same label. Very different relationship to your long-term health.

What about protein, B12, and other nutrients?

If you’re reading this with a raised eyebrow, I get it. I used to be a financial analyst—I can’t help double-checking the numbers.

When we talk lifespan, we’re really talking about decades of small daily choices compounding over time. That includes hitting your nutrition basics.

From a practical standpoint, vegans should prioritize:

• Vitamin B12 (through fortified foods or a supplement)

• Iodine (iodized salt or a supplement if needed)

• Long-chain omega-3s (ALA sources like flax/chia/walnuts; consider an algae-based DHA/EPA supplement if intake is low)

• Vitamin D (sun, fortified foods, or supplement depending on where you live and your blood levels)

• Calcium (fortified milks, tofu set with calcium, leafy greens)

• Iron and zinc (legumes, seeds, whole grains; pair iron with vitamin C for better absorption)

No fear-mongering here—just smart planning. A well-planned vegan diet can meet your needs at every life stage. But “well-planned” is doing some heavy lifting in that sentence.

Confounding is real (and researchers try to handle it)

A fair question: how do we know it’s the diet and not the lifestyle that often travels with it?

Many vegetarians and vegans also tend to smoke less, exercise more, and maintain a healthier weight. Good cohort studies adjust for these differences—age, BMI, activity, smoking, alcohol, education, and more—but observational designs can’t prove causation.

That doesn’t make the findings flimsy; it just means we should hold them with a scientist’s humility and a pragmatist’s eye.

If you love the outdoors and move your body regularly (hello, fellow trail runners), the benefits of a plant-heavy diet likely layer on top of those habits.

The opposite is also true: a sedentary, stressed lifestyle can blunt the advantage of a decent diet.

What I tell friends who ask, “So… should I go vegan for longevity?”

I tell them to think in gradients rather than absolutes. What matters most for lifespan is nudging your overall pattern toward fiber-rich, minimally processed plants while keeping nutrients covered.

Simple, longevity-friendly moves:

• Build your meals around plants: a legume + a grain + a heap of vegetables + some healthy fat. Boring? Only if you never use spices.

• Make nuts and seeds a daily habit.

• Swap refined grains for whole grains most of the time.

• Keep ultra-processed foods (even the vegan ones) as occasional extras.

• Supplement B12 if you’re vegan; consider D and algae omega-3s based on your context.

• Check in on your labs periodically with a healthcare professional, especially if you’re changing your diet.

I’ve seen clients feel less overwhelmed when they treat plant-based eating like a portfolio: diversify, minimize the “junk bonds,” and automate the good decisions.

Who might not see the benefit?

Two groups come to mind:

• The “plant-based but ultra-processed” crowd. If most of your calories come from refined carbs, added sugars, and fried foods, the longevity dial won’t budge much—vegan or not. The research linking plant-based diets to lower mortality is about dietary patterns rich in whole plants, not just the absence of meat.

• People under-fueling or under-protein-ing. It’s absolutely possible to get adequate protein on a vegan diet, but you still have to eat enough, and distribute protein across the day. Older adults, in particular, benefit from paying attention to total protein and resistance training to preserve muscle—both matter for healthy aging.

The bottom line (and how to act on it today)

What’s the truth, according to researchers? The center of gravity of the evidence points to this: diets centered on whole plant foods—vegan or close to it—are linked with lower mortality and better cardiometabolic profiles.

That doesn’t mean vegans live forever or that meat-eaters can’t be healthy. It does mean that if you tilt your plate toward beans, greens, grains, and seeds, you likely tilt your odds.

A few parting thoughts I keep taped above my desk:

• “What we do most days matters more than what we do some days.” That applies to dinner as much as it does to training plans.

• Start with swaps you’ll actually keep—black bean chili for taco night, a farro–arugula bowl for lunches, soy yogurt with berries instead of pastry.

• Think additions, not just subtractions: add a cup of beans a day, add a big salad, add a handful of walnuts. When you crowd your plate with plants, you naturally crowd out the stuff that doesn’t serve your future self.