Assessing Myths of Animal-Based Foods: Effects on Inflammation and Disease

Originally written by Katie Petit, Dietetic Intern. Updated with new 2025–2026 research by Heidi Moretti, MS, RD, CLT.

Inflammation

Inflammation is the body’s innate immune response to injury, illness, or infection, and it’s an essential step in the healing process.¹ In acute inflammation, warm, red, and swollen skin surrounds inflamed, injured tissue while the body deploys cytokines — proteins that act as messengers to alert and direct immune cells to fight off the illness or infection.² Although inflammation is integral to healing, prolonged (chronic) inflammation poses a real threat to health. Inflammation shifts from acute to chronic when the injured or infected site doesn’t heal efficiently, and it can persist for months or years, affecting nearly every system in the body.^1–3 Chronic inflammation is an underlying factor in many diseases, including autoimmune conditions, neurological conditions, cardiovascular disease, type 2 diabetes, cancer, liver disease, and kidney disease.⁴ Nutrition is one of the most powerful levers we have for reducing chronic inflammation, which is exactly why the diet-and-inflammation conversation deserves an evidence update rather than blanket rules.

A Quick Primer: Why Most Nutrition Headlines Rest on Weak Evidence

Before diving into specific foods, it’s worth pausing on something most nutrition coverage skips entirely: not all evidence is created equal, and the large majority of nutrition claims you’ve ever read — including the original decades-old case against saturated fat, red meat, and full-fat dairy — come from a type of study that sits near the bottom of the evidence hierarchy: observational (epidemiological) research.

Observational studies — cohort studies, case-control studies, cross-sectional surveys — track what people already eat and see what health outcomes correlate with it. They’re valuable for generating hypotheses, but they cannot establish that one thing causes another, for a few specific and largely unfixable reasons that a 2018 methods paper from Stanford’s John Ioannidis and colleagues lays out clearly.⁴⁶ First, the effect sizes typically detected in nutrition epidemiology are tiny — often in the range that’s easily created or erased entirely by confounding factors researchers didn’t measure or couldn’t fully control for, like income, education, exercise habits, smoking status, or overall dietary pattern.⁴⁶ Second, diet itself is notoriously hard to measure accurately; most large cohort studies rely on food frequency questionnaires asking people to recall what they ate over the past year, a method with substantial, well-documented error.⁴⁶ Third, because so many foods and nutrients are correlated with each other (people who eat more red meat also tend to differ from vegetarians in dozens of other ways at once), it’s extremely difficult to isolate the effect of any single food.

A widely cited 2013 analysis illustrates just how noisy this gets in practice: when researchers pulled random ingredients from a cookbook and searched the literature, the substantial majority already had at least one published study linking them to either an increased or decreased cancer risk — a demonstration of how easily statistical noise in this type of research gets reported as a meaningful finding.⁴⁷ This is also why randomized controlled trials designed specifically to test conclusions drawn from observational cohort studies frequently fail to confirm them, and sometimes find the opposite effect.

None of this means observational research is worthless — it’s often the only ethical or practical way to study long-term diet patterns, and it’s genuinely useful for generating hypotheses that better-designed trials can then test. But it means a single cohort study finding that people who eat more of food X have more (or less) of disease Y is, on its own, weak evidence at best — regardless of which direction it points or how confidently a headline states it. Throughout this post, I’ve tried to lean on randomized controlled trials, risk-stratified meta-analyses of trial data, and mechanistic evidence wherever it exists, precisely because that evidence sits higher on the hierarchy than the observational associations that originally shaped decades of dietary guidance.

Plant-Based: Hot Topic

In recent years, plant-based and plant-forward diets have dominated the wellness conversation, growing in popularity as a proposed solution for both environmental and personal health. People adopt this pattern for a variety of reasons — reducing their environmental footprint, supporting animal welfare, or more closely emulating the Mediterranean diet, which is associated with longevity and reduced rates of non-communicable disease and inflammation.^5–10 The Mediterranean pattern prioritizes whole grains, fruits, vegetables, heart-healthy fats such as omega-3s from fish, extra virgin olive oil, and avocados, along with meat and dairy in moderation. But whole grains aren’t automatically inflammation-neutral for everyone: sensitivities to antinutrients and gluten can trigger the very inflammation a plant-forward diet is meant to prevent.

It’s true that more plants — fruits, vegetables, whole grains — provide fiber and protective phytochemicals. But given the push to limit animal products for the sake of inflammation and heart health, what does the current evidence actually say about whole animal foods like beef and dairy?

Related post: The Best Canned Salmon Options

Animal Products and Saturated Fats

Alongside the push toward plant-based eating, highly nutritious animal-based foods containing saturated fat have often been cast aside in favor of polyunsaturated fats from fish, avocados, and olive oil. Saturated fat is an essential source of dietary fat and energy, found mainly in animal-based foods like meat and dairy, along with plant sources such as coconut and tropical oils.

Intake of saturated fat has been cautioned against for decades, notably since Ancel Keys’ lipid hypothesis of the 1950s.^11,12 Keys theorized a direct relationship between dietary saturated fat and cholesterol and the incidence of coronary heart disease.¹¹ This “diet-heart hypothesis,” based largely on observational data, has shaped guidance from organizations including the American Heart Association and the USDA/HHS Dietary Guidelines for Americans.¹³

Since its inception, the saturated fat theory has remained a point of contention in nutrition science.^11–14 And the newest research — published in just the last few months — has pushed that conversation even further.

The 2025–2026 Update: Saturated Fat Risk Isn’t One-Size-Fits-All

This is the section that has changed the most since this post was first published, and it’s directly relevant to how I approach nutrition with my own MRT/LEAP clients: population-wide advice and individualized advice are not the same thing.

In December 2025, researchers published the largest risk-stratified systematic review to date on saturated fat and cardiovascular outcomes in Annals of Internal Medicine, pooling 17 randomized controlled trials and 66,337 participants.²⁸ Rather than treating “reduce saturated fat” as a single universal recommendation, the reviewers split the data by each person’s baseline cardiovascular risk.

Overall, the risk-stratified evidence showed low-to-moderate certainty reductions in all-cause mortality (RR 0.96), cardiovascular mortality (RR 0.93), nonfatal heart attack (RR 0.86), and stroke (RR 0.83) with saturated fat reduction.²⁸ But when the authors broke the data down by baseline risk, the picture changed meaningfully: people already at high cardiovascular risk saw a real reduction in cholesterol and cardiovascular events when they cut saturated fat (especially when they replaced it with polyunsaturated fat), while people at low-to-moderate risk did not see the same benefit over the study’s five-year window.²⁹

That finding immediately became politically charged — it landed right as the 2025–2030 Dietary Guidelines for Americans were being finalized, with HHS Secretary Robert F. Kennedy Jr. promoting full-fat dairy, red meat, and beef tallow, and mainstream nutrition scientists pushing back on any suggestion that saturated fat is broadly harmless.²⁹ Tufts nutrition scientist Alice Lichtenstein, who wasn’t involved in the review, pointed out an important nuance: the study measured treatment effects in people who already had elevated risk, not prevention effects in people who don’t — and biomarkers like LDL cholesterol are exactly why we can identify who’s headed toward cardiovascular trouble before waiting decades for outcomes data.²⁹

My takeaway for clients: this is not permission to disregard saturated fat categorically, nor is it evidence that the old blanket “avoid all saturated fat” advice was correctly calibrated for every person. It’s a research-backed argument for exactly what I already practice — assess your own risk markers — lipid panel, ApoB, inflammatory markers, blood pressure, family history, and where relevant, your own food sensitivity profile — rather than applying one national guideline to every body. I go into this in much more depth, including why total cholesterol alone is a poor proxy for risk, in The Cholesterol Conversation We Actually Need to Have. This is the same “test not guess” logic behind my gut healing work and my own MRT/LEAP results.

Red Meat and Inflammation

Inflammation is one contributor to cardiovascular disease, and red meat has often been linked to inflammation and cardiovascular disease due to its saturated fat content and potential to raise LDL cholesterol.^15,16 A metabolomic study published in The American Journal of Clinical Nutrition analyzed data from older US adults in the Multi-Ethnic Study of Atherosclerosis, assessing plasma metabolites — substances produced when food is digested — alongside self-reported red meat intake.¹⁷ Once researchers adjusted for BMI, neither unprocessed nor processed red meat was associated with inflammatory markers like C-reactive protein (CRP), suggesting body weight, not red meat itself, was driving the original association.^18,19

A newer and much larger 2025 systematic review and meta-analysis published in Critical Reviews in Food Science and Nutrition adds important nuance to that picture.³¹ Pooling 22 randomized controlled trials (1,152 adults) and 10 observational studies (438,925 adults), the researchers found that in controlled trials, higher red meat intake was associated with a modest increase in CRP — but that association wasn’t universal. It was driven by a specific combination of factors.

In other words: the inflammatory signal from red meat in controlled trials was concentrated almost entirely in people who already had diagnosed cardiometabolic disease, ate mixed or processed forms, weren’t restricting calories, and ate at or above half a serving daily — not a universal effect of red meat itself.³¹ Researchers proposed that saturated fat in red meat may trigger innate immune signaling, and that heme iron may drive oxidative stress, but these mechanisms appear to matter most in people whose inflammatory baseline is already elevated.³¹ Independent of body weight and existing disease status, unprocessed red meat in moderate amounts does not appear to be the blanket inflammatory trigger it’s often portrayed as in headlines.

Red Meat and Cardiovascular Disease

The long-standing advice on red meat has been to minimize intake as much as possible. Research both supports and disputes a link between red meat and adverse cardiac outcomes. The Cochrane Heart Group’s systematic review and meta-analysis of 15 randomized controlled trials assessed the effects of reducing saturated fat intake on outcomes including cardiovascular morbidity and all-cause mortality, replacing saturated fat calories with carbohydrates, unsaturated fats, or protein. Reducing total saturated fat intake was associated with roughly a 17% reduction in cardiovascular disease risk; replacing saturated fat with polyunsaturated fat produced a 21% risk reduction, and replacing it with carbohydrates produced a 16% reduction, while other substitutions had little to no effect.²⁰ Although polyunsaturated fats and complex carbohydrates showed benefits, overall cardiovascular event risk wasn’t dramatically different across groups.²⁰

A February 2026 clinician’s guide from the American College of Cardiology’s Nutrition and Lifestyle Work Group, published in JACC: Advances, sorted several of today’s most debated animal-fat-adjacent foods into three evidence tiers: clear harm, insufficient evidence either way, and clear benefit.³² Beef tallow specifically landed in the “evidence of harm” category due to its LDL-raising effect, with the review’s authors noting that data supporting beef tallow as healthier than seed oils “is lacking,” while evidence of possible harm is considerable.³³ That’s a useful distinction: whole, unprocessed red meat consumed in reasonable amounts is a very different food, metabolically, than concentrated tallow used as a cooking fat. And LDL-raising isn’t automatically the same thing as cardiovascular harm — particle size, ApoB, and inflammatory status all shape how much a given LDL number actually matters, a topic I unpack fully in The Cholesterol Conversation We Actually Need to Have.

Dairy and Inflammation

Dairy garners mixed reviews — some consider it inflammatory, while others have no issue with it. For those with a casein allergy (a milk protein), dairy triggers an inflammatory response ranging from mild to life-threatening, so plant-based options make sense for that group.²¹ An estimated 68% of the world’s population experiences lactose intolerance, typically developing after infancy, though goat milk is often better tolerated due to its differing protein profile and lower lactose content.^22,23

Aside from those with allergies and intolerances, cow milk is appropriate for most people and beneficial for human health.²¹ Dairy is a rich source of saturated fat, which explains its assumed link to inflammation and why current guidelines still favor low-fat or fat-free dairy. A 2017 review in Critical Reviews in Food Science and Nutrition found weak but significant evidence of anti-inflammatory properties in dairy, challenging prior assumptions.²⁵ Fermented dairy with live active cultures, like kefir or yogurt, supports a healthier gut microbiome, which may further reduce inflammation.²¹

Dairy and Cardiovascular Disease

For the same reasons red meat intake is often cautioned, low-fat dairy has traditionally been recommended over full-fat, on the assumption that reduced saturated fat means reduced LDL cholesterol and cardiovascular risk.²⁶ A randomized controlled trial in the American Journal of Clinical Nutrition examined dairy’s complex food matrix effects on serum lipids and cardiovascular risk factors in 66 weight-stable adults with metabolic syndrome. After a 4-week limited-dairy run-in, participants followed either a low-fat or full-fat dairy pattern (3.3 daily servings) for 12 weeks. There was no impact on fasting total, LDL, or HDL cholesterol, triglycerides, or free fatty acids across groups, and no difference in diastolic blood pressure — though the low-fat dairy group showed a modest edge on systolic blood pressure.²⁶

That single trial’s findings have since been reinforced at a much larger scale. In 2025, an international panel of nutrition researchers convened specifically to re-examine “Saturated Fat in Dairy and Cardiovascular Disease,” publishing their consensus in the American Journal of Clinical Nutrition.³⁰ Their conclusion: current evidence indicates that milk, yogurt, and cheese — irrespective of fat content — are neutrally associated with cardiovascular disease risk.³⁰ A 2025 Norwegian cohort study of adults followed from the 1970s through the 1980s found no clear excess cardiovascular mortality risk from whole milk compared with low-fat milk once other factors were accounted for, and a 2026 dose-response meta-analysis in Frontiers in Nutrition similarly noted that dairy’s association with cardiovascular mortality is highly heterogeneous by product type, rather than simply tracking fat percentage.^34,35 The February 2026 JACC: Advances clinician’s guide placed full-fat dairy squarely in the “lacking evidence for harm” category — not proven harmful, and not yet proven beneficial either, but no longer defensible as an automatic red flag.³²

Where Animal Foods Land in 2026: Harm, Neutral, or Benefit

The American College of Cardiology’s 2026 review is genuinely useful because it doesn’t try to force every controversial food into “good” or “bad.” It sorts each one by the actual strength of the population-level evidence behind it — placing beef tallow, ultra-processed foods, artificial sweeteners, and sugar alcohols in the “evidence of harm” category; full-fat dairy, MCT oil, monk fruit, and stevia in “lacking evidence of harm”; and seed oils and seafood in “evidence of benefit,” based on their effects on outcomes like LDL cholesterol across the general population.³² Notice what’s missing from the “harm” column: whole, unprocessed red meat and moderate dairy consumption. It’s the ultra-processed forms, added sugar alcohols, artificial sweeteners, and concentrated fats like tallow used as cooking oil that carry the strongest current evidence of harm — not the whole animal foods this post set out to evaluate.

An important caveat on seed oils, from my own clinical experience: a population-level “evidence of benefit” classification like the one above is built on aggregate outcomes — average LDL and cardiovascular event data across large groups of people. It says nothing about what happens in a person whose immune system actively reacts to a food. Seed oils can absolutely be inflammatory, and therefore harmful to cardiovascular health, in someone whose body mounts an immune response to them. In more than 25 years as a registered dietitian, and across my newer years incorporating MRT/LEAP testing into my practice, I have never once seen a panel come back with zero reactivity to every seed oil tested — in my clinical experience, some degree of reactivity to at least one seed oil shows up in essentially everyone I’ve tested. That doesn’t mean seed oils are universally dangerous, but it does mean the population-average conclusion and an individual’s actual physiological response can point in opposite directions at the same time, and only testing reveals which one applies to you.

This is precisely why I don’t treat “the research says X is beneficial” as the end of the conversation with clients. When we identify and reduce someone’s specific inflammatory triggers — whether that’s a seed oil, dairy, a specific protein, or something else entirely — the downstream effects on cardiovascular risk factors are often substantial, and not just through inflammatory markers directly. Dampening chronic, diet-driven inflammation through a LEAP elimination and reintroduction protocol tends to support several risk factors at once in my clients: easier body weight regulation as inflammatory signaling that drives fluid retention and metabolic dysfunction settles down, improved muscle performance and recovery once chronic low-grade inflammation stops interfering with training adaptation, and better gut health and nutrient absorption once the gut lining isn’t under constant immune assault. Those downstream shifts — weight, muscle function, gut integrity — are themselves established cardiovascular risk factors in their own right, which means individualized inflammation management can move the needle on heart health through multiple pathways simultaneously, not just the single pathway a population-level food classification captures.

Putting It All in Perspective: How Does Diet Compare to Stress as a Cardiovascular Risk Factor?

Every effect size discussed above is worth sitting with for a moment. Reducing saturated fat moved cardiovascular risk by roughly 4–17% (RR 0.83–0.96), and only in people already at high risk.²⁸ Red meat’s inflammatory signal only appeared under a narrow set of conditions.³¹ These are real, but modest, effect sizes. So how do they compare to a risk factor that gets far less attention at the dinner table: chronic psychological stress?

The landmark INTERHEART study — a case-control analysis of over 24,000 people across 52 countries — found that nine modifiable risk factors together accounted for roughly 90% of the population-level risk of a first heart attack worldwide.^36,37 Psychosocial stress wasn’t a minor entry on that list. It ranked as the third-largest contributor, behind only the ApoB/ApoA1 lipid ratio and smoking — and it outranked diabetes, abdominal obesity, and physical inactivity.³⁷

Looked at as individual odds ratios rather than population share, the comparison gets even more striking. A single stressor — psychosocial stress broadly defined — carried an odds ratio of 2.67 for a first heart attack, and permanent, unrelenting work stress specifically carried an odds ratio of roughly 2.14–2.17, with a clear dose-response relationship: periodic stress raised risk more modestly (OR ~1.38–1.45), while chronic, unrelenting stress raised it substantially more.^37,38 For comparison, that’s a larger individual effect size than diabetes (OR 2.37) and meaningfully larger than hypertension (OR 1.91) — two conditions most people would never consider optional to treat.³⁷

Newer research reinforces the mechanism. A December 2025 study from Mass General Brigham found that in people with depression and anxiety, stress-related brain activity, nervous system dysregulation, and chronic inflammation appear to directly drive elevated cardiovascular risk — with the combination of both conditions carrying more risk than either alone.³⁹ A 2025 narrative review further outlines the mechanism many of my clients already know from their own labs: chronic stress drives sustained cortisol and other glucocorticoid release, which promotes the same pro-inflammatory cascade — including TNF-α secretion and endothelial dysfunction — that accelerates atherosclerotic plaque development.⁴⁰ This is the same cortisol-inflammation connection I cover in depth in Cortisol Fix, and it’s a big part of why I don’t think cardiovascular risk conversations are complete when they stop at the dinner plate.

None of this means diet doesn’t matter — the research throughout this post shows it clearly does, especially for people already at elevated risk. But it does mean that if you’re doing everything “right” nutritionally and still worried about your heart, unmanaged chronic stress may be a bigger lever to address than another round of scrutinizing saturated fat grams. A comprehensive risk picture has to include both.

Reading This Research Critically: A Note on Food and Pharmaceutical Industry Influence

Part of “test not guess” is applying the same scrutiny to the research itself that I apply to a client’s labs. So in the interest of full transparency, here’s what a look at the funding and disclosure statements behind several of the studies cited above turned up — food industry ties first, then a look at pharmaceutical influence on the cholesterol-testing guidance discussed earlier in this post.

The 2025 red meat and CRP meta-analysis discussed earlier in this post carries a direct industry connection worth knowing about: its senior author disclosed research funding, travel, or consulting income from the Pork Checkoff, National Pork Board, Beef Checkoff, National Cattlemen’s Beef Association, American Egg Board, and National Dairy Council, among others, and two additional co-authors disclosed National Cattlemen’s Beef Association funding specifically.³¹ That doesn’t make the findings wrong — the methodology is transparent and peer-reviewed — but it’s relevant context when a meat-industry-funded analysis concludes that red meat’s inflammatory link is more conditional than headlines suggest. A separate 2025 systematic review in the American Journal of Clinical Nutrition examined this exact pattern across the broader red meat literature and found that industry-sponsored trials on unprocessed red meat and cardiovascular risk do tend to report outcomes that differ from independently funded research.⁴⁴

The 2025 dairy fat neutrality review cited in the dairy sections above has its own disclosure to know about: it originated from a closed workshop organized and funded by the Dutch Dairy Association, which covered financial support and travel for most of the panel’s authors, and one author separately disclosed a funding relationship with Dairy Management Inc., the U.S. dairy checkoff organization.³⁰

The February 2026 clinician’s guide that classified seed oils as “evidence of benefit” and beef tallow as “evidence of harm” has a more mixed funding picture across its 13 authors — several disclosed research funding or advisory relationships spanning the National Cattlemen’s Beef Association, American Egg Board, Soy Nutrition Institute Global, The Peanut Institute, and Beyond Meat, and one author founded a packaged food company.³² Interestingly, that mix cuts across categories rather than lining up neatly with the panel’s conclusions — authors with beef industry funding still placed beef tallow in the “harm” tier, for what it’s worth. By contrast, I found no disclosed industry funding for the authors of the December 2025 risk-stratified saturated fat review or the original INTERHEART studies.

Pharmaceutical industry influence deserves its own look, too — particularly around the ApoB testing gap discussed earlier in this post. The 2026 ACC/AHA dyslipidemia guideline that finally gave ApoB testing a Class I recommendation is a genuinely useful update grounded in solid outcomes data for statins, ezetimibe, and PCSK9 inhibitors.⁴² But an independent tally of that guideline’s own published disclosure appendices found that while its chair and vice-chair reported no relevant industry relationships, roughly half of the remaining 31 writing committee members disclosed relationships relevant to the guideline’s content with pharmaceutical manufacturers, imaging companies, digital health companies, or genetic testing companies — several with ties spanning nearly the entire landscape of newer lipid-lowering drugs the guideline addresses. More than two-thirds of the 29-member peer review committee, whose role is to independently check the writing committee’s conclusions, disclosed relevant conflicts as well.⁴⁸ None of this is hidden; it’s disclosed in the guideline’s own appendices, and the underlying statin and PCSK9 inhibitor trial data are genuinely strong. But it’s worth naming plainly: a guideline that broadens testing criteria and lowers treatment thresholds also expands the market for the tests and drugs made by the companies many of its authors have financial relationships with. That’s not a reason to ignore ApoB — the biology and the outcomes data both hold up — but it’s a reason to keep asking who benefits before treating any single guideline as the final word.

I’m not sharing any of this to suggest the research should be dismissed — rigorous peer review and transparent methodology matter more than funding source alone, and industry funding doesn’t automatically invalidate a finding. But nutrition and cardiology research are both disproportionately funded and reviewed by industries with a direct financial stake in the outcome, compared to most other areas of medicine, and disclosed conflicts of interest are worth factoring in as one more piece of context, the same way you’d want to know who funded a study before changing your own diet or treatment plan based on it.⁴⁵ This is exactly why I lean on risk-stratified, mechanism-based reasoning and individual testing rather than any single study, expert panel, or guideline — population-level health science, however well-conducted, is still produced within an ecosystem of food and pharmaceutical companies with a direct stake in the answer.

Conclusions

As noncommunicable diseases like cardiovascular disease, cancer, diabetes, and respiratory disease remain leading causes of death worldwide, it’s essential to keep evaluating nutrition’s role in prevention and health promotion honestly — including when new evidence complicates old assumptions. The research from just the past year reinforces two things I’ve built my entire clinical practice around: first, that whole foods with complex nutrient matrices behave differently than isolated nutrients pulled out of context, and second, that “high risk” and “low risk” individuals often need genuinely different guidance rather than one national recommendation applied uniformly.^27,28,30 Saturated fat reduction appears to meaningfully help people already at elevated cardiovascular risk, while red meat’s inflammatory effect is concentrated in people with existing cardiometabolic disease eating higher, less-restricted intakes — and full-fat dairy, across multiple 2025–2026 reviews, continues to look neutral for most people’s cardiovascular risk.^28,30,31 If you’re trying to figure out where you personally fall on that risk spectrum, working with a functional nutrition provider who looks at your actual labs and history — and who takes chronic stress and cortisol dysregulation just as seriously as your lipid panel — rather than applying population-wide averages to your individual body, is going to get you further than any single headline about beef or butter.

Frequently Asked Questions

Does red meat cause inflammation?
Not universally. A 2025 meta-analysis found that red meat raised the inflammatory marker CRP mainly in people who already had cardiometabolic disease, ate mixed or processed forms, weren’t restricting calories, and consumed 0.5 servings or more per day. Once adjusted for body weight, moderate unprocessed red meat intake was not consistently associated with inflammation in healthy adults.

Is saturated fat bad for everyone?
A December 2025 risk-stratified review of 17 randomized trials found that reducing saturated fat meaningfully lowered cardiovascular risk in people already at high cardiovascular risk, but showed little measurable benefit for people at low-to-moderate risk over a 5-year period.

Is full-fat dairy bad for heart health?
A 2025 expert panel review published in the American Journal of Clinical Nutrition concluded that milk, yogurt, and cheese are neutrally associated with cardiovascular disease risk regardless of fat content. A February 2026 cardiology review similarly placed full-fat dairy in the “lacking evidence of harm” category.

Is beef tallow healthier than seed oils?
Current cardiology evidence says no. A 2026 clinician’s guide from the American College of Cardiology’s Nutrition and Lifestyle Work Group placed beef tallow in the “evidence of harm” category due to its LDL-raising effect, while seed oils were placed in the “evidence of benefit” category.

Are seed oils inflammatory?
They can be, in people whose immune system reacts to them. Population-level cardiology research classifies seed oils as “evidence of benefit” based on average LDL and outcomes data, but that average doesn’t capture individual immune reactivity. In clinical MRT/LEAP food sensitivity testing, some degree of reactivity to at least one seed oil is extremely common — individual testing, not population averages, is what reveals whether seed oils are helping or hurting your specific inflammatory profile.

How does stress compare to diet as a heart disease risk factor?
In the landmark INTERHEART study of 24,767 people across 52 countries, psychosocial stress carried a higher population attributable risk (32.5%) for a first heart attack than diabetes, abdominal obesity, or physical inactivity — ranking third behind only lipid ratios and smoking. Chronic, unrelenting work stress specifically carried an odds ratio of roughly 2.14, a larger individual effect size than hypertension.

Why is epidemiological (observational) nutrition research considered weak evidence?
Observational studies can only show correlation, not causation, because they can’t control for confounding factors like income, exercise, smoking, or overall dietary pattern. Effect sizes in nutrition epidemiology also tend to be small enough to be easily created or erased by unmeasured confounding, and self-reported diet data is notoriously imprecise. This is why randomized controlled trials, which this post prioritizes wherever possible, sit higher on the evidence hierarchy.

Is nutrition research funded by the food industry?
Often, yes. Several studies discussed in this post disclose direct food industry funding or advisory relationships — including meat, dairy, and other food-industry ties among the authors of key 2025–2026 papers on red meat inflammation, dairy fat, and cardiovascular nutrition guidance. This doesn’t automatically invalidate a study’s findings, but it’s worth factoring in when interpreting population-level nutrition research, since industry-sponsored studies have been shown to more often report outcomes favorable to their funder.

Does the pharmaceutical industry influence cardiovascular guidelines?
It can. An independent review of the 2026 ACC/AHA dyslipidemia guideline’s own published disclosure statements found that roughly half of its writing committee and more than two-thirds of its peer review committee disclosed relationships with pharmaceutical, imaging, digital health, or genetic testing companies relevant to the guideline’s content. The underlying statin and PCSK9 inhibitor outcomes data are still solid, but a guideline that broadens testing and lowers treatment thresholds also expands the market for the products many of its authors have financial ties to — worth knowing before treating any single guideline as the final word.

References

1. Cleveland Clinic. Inflammation. March 22, 2024. my.clevelandclinic.org
2. Cleveland Clinic. Cytokines. January 3, 2023. my.clevelandclinic.org
3. Yale Medicine. How Inflammation Affects Your Health. April 8, 2022. yalemedicine.org
4. Furman D, Campisi J, Verdin E, et al. Chronic inflammation in the etiology of disease across the life span. Nat Med. 2019;25(12):1822-1832.
5. United Nations. Your guide to climate action: Food. un.org
6. Animal Aid. Going vegan for the animals. animalaid.org.uk
7. Mayer, BA. 8 Ways the Mediterranean Diet Can Help You Live a Longer and Healthier Life. Healthline. April 25, 2023.
8. Tepper S, Kissinger M, Avital K, Shahar DR. The Environmental Footprint Associated With the Mediterranean Diet, EAT-Lancet Diet, and the Sustainable Healthy Diet Index. Front Nutr. 2022;9:870883.
9. McManus KD. What is a plant-based diet and why should you try it? Harvard Health Blog. March 28, 2024.
10. Alcorta A, Porta A, Tárrega A, Alvarez MD, Vaquero MP. Foods for Plant-Based Diets: Challenges and Innovations. Foods. 2021;10(2):293.
11. Fallon S, Enig MG. Nourishing Traditions. 2nd ed. NewTrends Publishing; 2001.
12. Bjarnadottir A. 5 Studies on Saturated Fat – Time to Retire the Myth? Healthline. June 23, 2023.
13. Astrup A, Teicholz N, Magkos F, et al. Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based? Nutrients. 2021;13(10):3305.
14. Forouhi NG, Krauss RM, Taubes G, Willett W. Dietary fat and cardiometabolic health. BMJ. 2018;361:k2139.
15. Cleveland Clinic. 5 Types of Foods That Cause Inflammation.
16. Bandeira Silva de Medeiros GC, et al. Red meat consumption, risk of incidence of cardiovascular disease and cardiovascular mortality. Medicine (Baltimore). 2019;98(38):e17271.
17. National Institute of Health. Dictionary of Cancer Terms: Metabolite.
18. Wood AC, Graca G, Gadgil M, et al. Untargeted metabolic analysis investigating links between unprocessed red meat intake and markers of inflammation. Am J Clin Nutr. 2023;118(5):989-999.
19. Baylor College of Medicine. Is red meat intake linked to inflammation? EurekAlert! October 26, 2023.
20. Hooper L, Martin N, Jimoh OF, Kirk C, Foster E, Abdelhamid A. Reduction in saturated fat intake for cardiovascular disease risk. Cochrane Database Syst Rev. 2020;8(8):CD011737.
21. Williams C. Does Dairy Cause Inflammation? Here’s What a Dietitian Says. EatingWell. November 30, 2022.
22. National Institute of Diabetes and Digestive and Kidney Diseases. Definitions & Facts for Lactose Intolerance. February 2018.
23. Malik TF, Panuganti KK. Lactose Intolerance. NCBI. April 17, 2023.
24. Metzger M. Goat milk versus cow milk: a comparison. Michigan State University Extension. July 22, 2022.
25. Bordoni A, Danesi F, Dardevet D, et al. Dairy products and inflammation: a review of the clinical evidence. Crit Rev Food Sci Nutr. 2017;57(12):2497-2525.
26. Schmidt KA, Cromer G, Burhans MS, et al. Impact of low-fat and full-fat dairy foods on fasting lipid profile and blood pressure. Am J Clin Nutr. 2021;114(3):882-892.
27. Miller GD, Ragalie-Carr J, Torres-Gonzalez M. Perspective: Seeing the Forest Through the Trees: The Importance of Food Matrix in Diet Quality and Human Health. Adv Nutr. 2023;14(3):363-365.
28. Steen JP, Klatt KC, Chang Y, et al. Effect of Interventions Aimed at Reducing or Modifying Saturated Fat Intake on Cholesterol, Mortality, and Major Cardiovascular Events: A Risk Stratified Systematic Review of Randomized Trials. Ann Intern Med. 2026;179:242-255. acpjournals.org
29. Cooney E. Free pass or failing grade for saturated fats? Review sets off scientific and political debate. STAT News. December 15, 2025. statnews.com
30. Lamarche B, Astrup A, Eckel RH, et al. Regular-fat and low-fat dairy foods and cardiovascular diseases: perspectives for future dietary recommendations. Am J Clin Nutr. 2025;121(5):956-964. pmc.ncbi.nlm.nih.gov
31. Wang Y. Red meat intake and its influences on inflammation and immune function biomarkers in human adults: a systematic review and meta-analysis of randomized controlled trials and observational studies. Crit Rev Food Sci Nutr. 2025. tandfonline.com
32. Miller M, et al. A Clinician’s Guide for Trending Cardiovascular Nutritional Controversies in 2026. JACC Adv. 2026;5:102591. jacc.org
33. Today.com. Is Beef Tallow Healthier Than Seed Oils for Heart Health? Cardiologists Weigh In. May 2026. today.com
34. Low-fat and whole milk consumption in relation to cardiovascular disease-related and all-cause mortality: a prospective cohort study in 3 Norwegian counties. Am J Clin Nutr. 2025;122(4):1093-1102. ajcn.nutrition.org
35. The dose-response relationship between dairy product intake and all-cause and cardiovascular mortality risk. Front Nutr. 2026;13:1731841. frontiersin.org
36. Yusuf S, Hawken S, Ôunpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. 2004;364:937-952.
37. Rosengren A, Hawken S, Ôunpuu S, et al. Association of psychosocial risk factors with risk of acute myocardial infarction in 11,119 cases and 13,648 controls from 52 countries (the INTERHEART study). Lancet. 2004;364:953-962.
38. Levine GN. Psychological Stress and Heart Disease: Fact or Folklore? Am J Med. 2022.
39. Mass General Brigham. Stress-related brain signals drive risk of cardiovascular disease in people with depression and anxiety. December 17, 2025.
40. Impact of Chronic Psychological Stress on Cardiovascular Disease Risk: A Narrative Review. Heart Mind. 2025.
41. Empirical Health. ApoB vs. LDL Cholesterol: fewer than 1% of insured Americans tested annually. 2025.
42. HCPLive. Expert Insights: Lp(a) and ApoB in the 2026 Dyslipidemia Guidelines. 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline. J Am Coll Cardiol. Published online March 13, 2026.
43. BlueRipple Health. Why Hasn’t ApoB Testing Become Standard? November 29, 2025.
44. Tibaes JRB, et al. Industry study sponsorship and conflicts of interest on the effect of unprocessed red meat on cardiovascular disease risk: a systematic review of clinical trials. Am J Clin Nutr. 2025;121(6):1315-1327.
45. Mozaffarian D. Conflict of interest and the role of the food industry in nutrition research. JAMA. 2017;317(17):1755-1756.
46. Trepanowski JF, Ioannidis JPA. Perspective: Limiting Dependence on Nonrandomized Studies and Improving Randomized Trials in Human Nutrition Research: Why and How. Adv Nutr. 2018;9(4):367-373.
47. Schoenfeld JD, Ioannidis JPA. Is everything we eat associated with cancer? A systematic cookbook review. Am J Clin Nutr. 2013;97(1):127-134.
48. Stein J. The 2026 ACC/AHA Dyslipidemia Guidelines: My Hot Take (independent analysis of the guideline’s Appendix 1 and 2 disclosure statements). March 14, 2026.