I’m mostly vegan—until I’m not. Most days I want beans, greens, and olive oil. Some days, my body demands liver, or broth, or chicken gizzards. I’d love to pretend this is tidy. It isn’t. And that’s the point of this essay: we eat with bodies, beliefs, budgets, and histories. We also eat with blind spots. Every camp—vegan, vegetarian, pescatarian, carnivore—has a moral story that flatters itself and ignores its own contradictions.
So this is my truce with the truth: I’ll lay out what each pattern gets right, where it falls, and what we know from serious research—environment, health, and ethics—without turning it into a purity contest.
The scoreboard we never look at: environment.
The most robust global analysis of food impacts (38,000 farms; 40 foods) shows the same headline every time: animal foods—especially beef and lamb—are climate and land-use-heavy compared to plants; variation is huge farm-to-farm, but even the best beef tends to out-pollute most plant proteins. Science+1
Zoom out from a single steak, and you see the whole system: food causes about 26% of global greenhouse gas emissions, uses half of habitable land, accounts for 70% of freshwater withdrawals, and causes most water pollution (eutrophication). Diet swaps matter more than “eating local” in many cases because the on-farm stage accounts for the majority of emissions. Our World in Data
Milk vs plant milks. On average, cow’s milk has around triple the greenhouse footprint and far higher land/ water use than oat/soy milks (almond is the outlier on water). That’s consistent across multiple syntheses. Our World in Data
Vegan hypocrisy check. Almonds are thirsty: estimates hover around ~10,000 liters per kg kernels (≈12 L per almond, with wide variation). In drought-stressed California, that’s not nothing. scholars.csus.edu
Avocado caveat. Avocados aren’t a crime, but Mexico’s boom has driven deforestation and water stress in parts of Michoacán; there’s now a push to certify against illegal clearing—so sourcing matters. PMC
Seafood nuance. Bivalves (mussels, oysters, clams) can be low-impact and even improve water quality. At the same time, many wild fisheries face climate-driven shifts and management challenges. Not all “fish” carry the same footprint or future. PMC
Regenerative grazing? Better grazing can build soil carbon in some contexts, but the evidence is mixed and location-specific; sequestration gains don’t usually offset methane emissions at scale. Beware miracle claims. Frontiers
The bigger reality. If we keep eating the way we do, food alone could add nearly 1°C of warming by 2100—three-quarters of it from methane-heavy foods like ruminant meat, dairy, and rice. Flexing toward plant-heavy patterns reduces that risk. Nature
Flexitarian advantage. Modeling in Science Advances finds plant-forward “flexitarian” diets (EAT-Lancet style) make the Paris goals more feasible by shrinking ag emissions and land pressure—without demanding 100% veganism from everyone. Science
And the elephant in the kitchen: food waste. Roughly a third of food is lost or wasted; accounting for waste can increase category emissions by ~40% in some analyses. Whatever we eat, wasting less matters. Le Monde.fr
Environmental verdict:
- If climate and land are your top concerns, a plant-heavy diet comes out on top, on average.
- Almonds/avocados aren’t saints. Source with eyes open.
- Bivalves can be a smart protein.
- “Regenerative everything” is not a get-out-of-methane card.
- Flexitarian shifts from high-impact meats do real good, fast. Science
The scoreboard we feel in our bodies: health
Cardiometabolic risk. Meta-analyses find vegetarian/vegan patterns lower cardiovascular disease risk overall, primarily via fiber, polyphenols, and lower saturated fat. ScienceDirect
But there’s a wrinkle. In EPIC-Oxford, vegetarians had lower ischemic heart disease but a modestly higher stroke risk (esp. hemorrhagic): about three extra strokes per 1,000 people over 10 years. It’s observational data; the mechanism is likely tied to B12/omega-3/ cholesterol levels and deserves nuance, not panic. BMJ
Nutrients to mind if you’re vegan or mostly-vegan: B12, iron, zinc, iodine, calcium, vitamin D, and long-chain omega-3s (DHA/EPA). All manageable with planning/fortification/ supplements; pretending they’re non-issues is how people get into trouble. PubMed
Plant milks. Many are lower-impact, but not all are nutritionally equivalent to dairy; check fortification (calcium, D, B12) and protein (soy and pea are closer to dairy than almond/oat). PMC
Pescatarian edge? Some cohorts show that pescatarians share many of the benefits of vegetarians, with additional omega-3s; the catch is sustainability and contaminants, depending on species and source. BMJ
Health verdict:
- Plant-heavy patterns consistently support heart health.
- Vegan works great if you do your homework on B12/iron/DHA, etc.
- A small stroke risk signal has emerged in one large cohort; it’s modest and not destiny.
- Pescatarian can be a pragmatic compromise if you choose low-trophic or bivalve species. ScienceDirect
The hypocrisy museum (guided tour)
Vegan hypocrisy.
- “Cruelty-free” isn’t footprint-free. Almond water, avocado deforestation, and plastic-heavy ultraprocessed substitutes all exist. Also, leather-free sneakers still rely on fossil inputs. scholars.csus.edu
- A perfect supply chain doesn’t exist. The honest vegan supplements B12, reads labels, and buys fewer pointless things.
Vegetarian hypocrisy.
- “I don’t eat meat,” but I live on cheese/eggs from the same industrial system I condemn. Dairy’s footprint usually exceeds plant alternatives; cage-free isn’t pasture. Our World in Data
- Health halo ≠ micronutrient coverage; iron and B12 can still be low.
Pescatarian hypocrisy.
- “It’s just fish” can mean trawled habitats, bycatch, and climate-shifting stocks. Or it can mean mussels. One of those looks a lot better than the other. Choose species like an adult. Nature
Carnivore/omnivore hypocrisy.
- “At least I’m honest.” Honest would mean acknowledging methane, land use, and the outsourced killing you never watch. Regenerative exceptions exist, but don’t erase averages. Science
Everyone’s hypocrisy.
- We moralize diets while binning leftovers. Food waste is the quiet scandal across all camps. Le Monde.fr
What I actually do (and why I still call myself a hypocrite)
I prefer vegan food. I feel great on lentils, tahini, olive oil, and vegetables. Then, very occasionally, I feel unwell and eat animal foods: liver for iron and retinol; gelatinous broths; sometimes chicken hearts or gizzards. I don’t pretend this is philosophically clean. But the human body is not a press release, and health is not a branding exercise. If you eat this way, do it consciously:
- Supplement what plant-only diets commonly miss (B12 always; consider D, iodine, iron, DHA). Track labs if you can. PubMed
- If you add animal foods episodically, choose small-footprint options (bivalves, small pelagics from well-managed fisheries; eggs from credible welfare standards) and skip high-impact beef/lamb except as a rare luxury. PMC
- Don’t buy the whole avocado/almond farm. Diversify fats and proteins; source thoughtfully. scholars.csus.edu
- Above all: waste less. The greenest steak is the one you didn’t toss. Le Monde.fr
The fairest summary I can give each camp.
Vegan (properly planned).
Pros: Lowest average environmental footprint; strong cardiometabolic data; aligns with animal-welfare ethics. Cons: Requires supplementation/fortification; watch protein quality and key micronutrients; some trendy vegan products are ultra-processed or resource-intensive. Science
Vegetarian.
Pros: Many health benefits; easier socially; less restrictive; lower footprint than omnivore. Cons: Can lean hard on dairy/eggs with higher impacts; nutrients (iron, B12) still need attention. ScienceDirect
Pescatarian.
Pros: Often good health outcomes; omega-3s; can be relatively low-impact if focused on bivalves and lower-trophic fish. Cons: Overfishing, bycatch, and climate shifts complicate sustainability; mercury/contaminants vary by species. BMJ
Omnivore (unrestricted).
Pros: Nutritionally easy; culturally frictionless; no supplements required. Cons: Highest average climate/land/water impacts driven by ruminant meats; animal welfare concerns; health outcomes vary widely with quality and quantity of meat. Science
Flexitarian (planetary-health style).
Pros: Big environmental wins with modest behavior change; nutritionally diverse; politically realistic. Cons: Still requires intention (what you do eat matters as much as what you skip). Science
What the climate math is begging us to do
Multiple lines of research say the quiet part out loud: even if energy gets clean, food systems can still blow our climate targets—unless we shift what we grow and eat, cut methane-heavy foods, improve practices, and slash waste. Flexitarian patterns (not ideological purity) buy us real time. Nature
The only honest rule I believe in
Eat like a grown-up with skin in the game. If you’re vegan, supplement and source with care. If you’re a vegetarian, don’t hide behind cheese. If you’re pescatarian, learn your species and pick bivalves often. If you’re an omnivore, stop pretending your beef is benign and treat it like caviar, not Tuesday. And all of us—stop wasting food.
I remain mostly vegan, sometimes not, always trying to waste less, buy better, and keep my lab work boring. I’m a hypocrite with goals. So are you. That’s not an insult; it’s an invitation.
Invitation accepted? Good. Start with tonight’s dinner. Make it plant-heavy. If you add animal foods, make them chosen, not default. And whatever you cook—finish it.
Key sources (for you, for readers, for critics):
- Global food impacts & diet comparisons: Poore & Nemecek, Science (2018); Our World in Data syntheses. Science
- Warming from food & flexitarian feasibility: Ivanovich et al., Nature Climate Change (2023); Humpenöder et al., Science Advances (2024). Nature
- Health outcomes: Landry et al., Am Heart J Plus (2024); EPIC-Oxford stroke/heart disease nuance, BMJ (2019). ScienceDirect
- Vegan nutrition adequacy: Bakaloudi et al., systematic review (2021) and newer syntheses (2025). PubMed
- Milk comparisons: Our World in Data; recent review on plant vs dairy milks. Our World in Data
- Almond/avocado impacts: Fulton (2019) on water; Denvir et al. (2021) on deforestation; Michoacán certification news (2024). scholars.csus.edu
- Seafood/bivalves/climate: Zhang et al. (2025) review; climate effects on small pelagics. PMC
- Waste & system boundaries: Mandouri et al. (2025) LCA meta-analysis; UNEP food waste reporting. Nature
