The Long Game
Fifty years of nutrition science vs. the wellness industrial complex — and why what you eat still matters more than what you’re told about it
The Long Ride with Greg Pallone
Ever since I survived my encounter with cancer over 20 years ago, I have spent a lot of time reading about nutrition, diet, exercise, and mindfulness. I’m embarrassed to recount some of the titles — let’s just say I once owned a book about eating for your blood type and leave it at that. But I was determined to bend the bell curve for cancer recurrence in my favour.
Over the past twenty years, I have also experimented with most of the diet trends: low-fat, low-carb, Keto, intermittent fasting, Paleo, and at least one juice cleanse I’d rather forget. I think I’m missing some, but you get the point.
What eventually drew me out of the diet-book rabbit hole and into the scientific literature was a simple realization: the books were written to sell books. But the studies were written to find out.
Today, I spend a lot of time researching the available literature for this series and for my ongoing education. One of the things science teaches you, if you stay with it long enough, is the difference between a finding and a trend.
A finding is a result or what we learn from a study. A trend is what happens when the wellness industry gets hold of it. Somewhere between the peer-reviewed journal and your Instagram feed, a nuanced piece of nutritional epidemiology becomes a headline, the headline becomes a rule, and the rule becomes a product. The process is fast, profitable, and often wrong. And the people most likely to be caught in its wake are exactly the people this series is written for — adults in their fifties, sixties and seventies who are paying serious attention to what they eat and trying to make good decisions with imperfect information.
The antidote is not more influencer content. It is understanding how we know what we know about food, our environment and what we can do to improve our healthspan. Which is where Walter Willett comes in.
—
Walter Willett is eighty years old, still publishing, and the most-cited nutrition scientist in the world. He is a professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health, where he served as chair of the nutrition department for twenty-five years. He has published more than 2,000 peer-reviewed research papers. He has also been wrong before, has said so publicly, and has changed course based on the evidence. That last part is what makes him worth listening to.
His method is built on a deceptively simple idea: follow a large group of people for a very long time, measure what they eat at regular intervals, and track their health. Not for a few weeks. For decades.
The Nurses’ Health Study, which Willett has led since 1980, has tracked nearly 280,000 women and men for more than forty years. It is one of the largest and longest-running dietary investigations in the history of medicine. The conclusions it produces are neither dramatic nor quick. Over time, they are extremely reliable.
This is the fundamental difference between Willett’s research and wellness content. A wellness influencer can tell you what happened to them when they changed their diet last month. Willett can tell you what happened to 280,000 people over the past four decades. Those are not the same kind of claims.
—
The most important thing to understand about Willett’s career is that it has largely been spent correcting mistakes in mainstream nutrition science—including those his own field enthusiastically promoted.
The biggest was about fat.
The dietary consensus of the 1980s held that fat was the enemy. All fat. The logic seemed sound: fat has more calories per gram than carbohydrates or protein; saturated fat raises LDL cholesterol; high LDL is associated with heart disease; therefore, eat less fat.
The USDA food pyramid of 1992 put fats and oils at the very top — use sparingly — and placed bread, pasta, and rice at the base, with six to eleven daily servings recommended. Millions of people followed this advice. Low-fat products flooded supermarkets. Yet rates of obesity, type 2 diabetes, and metabolic disease continued to climb.
Willett’s research from the Nurses’ Health cohorts found out why. When people reduced fat in their diets, they replaced it with something. And that something, in many cases, was highly refined carbohydrates — white bread, white rice, low-fat cookies, fat-free crackers.
Removing saturated fat and replacing it with refined starch did not improve cardiovascular outcomes. In many cases, it made them worse. The enemy was not fat. The enemy was the wrong kind of fat and the wrong kind of carbohydrate, consumed in the wrong proportions.
A 2025 interview in Vessel Plus, in which Willett addressed current controversies in cardiovascular nutrition, restated what his decades of research had established: the critical question in nutrition is never whether a food is good or bad in isolation. It is what you replace it with. He calls this the ‘compared to what?’ framework. And it is the question that most wellness content never asks.
—
The trans-fat story is the clearest example of what Willett’s method can do when it works.
In the late 1980s, Willett noticed something most nutritionists had overlooked. Natural vegetable oils were being partially hydrogenated — chemically altered to change their texture and extend shelf life. This process twisted the shape of essential fatty acid molecules. Willett described it at the time as throwing sand into a finely working Swiss watch. It was unlikely to improve the mechanism. It could possibly make it grind to a hard stop. He called this process trans fats.
His research subsequently showed that trans fats dramatically increased the risk of heart disease. Not modestly. Dramatically. The Nurses’ Health Study data made the case clearly enough that Willett spent much of the 1990s publicly pushing back against the food industry and the regulatory agencies that had declared partially hydrogenated oils safe.
The FDA finally banned trans fats in 2018 - approximately thirty years from Willett’s initial findings to regulatory action. That timeline is not an indictment of the science — it is a description of how slowly institutions absorb unwelcome evidence. The science itself was right all along.
The lesson for today’s reader is this: when someone on social media presents a compelling case that a common food is secretly poisoning you, the question to ask is not whether the claim sounds plausible. It is whether there is a Walter Willett somewhere who has spent thirty years following 280,000 people and arrived at the same conclusion. If the answer is no, wait for more evidence before adopting a new fad diet.
—
Which brings us to seed oils.
By now, you have almost certainly heard the claim. Seed oils — canola, soybean, sunflower, corn oil and others — are inflammatory, toxic, and responsible for the obesity epidemic. RFK Jr., in his role as US Secretary of Health and Human Services, has described them as poisoning Americans.
Some wellness influencers, rushing to get on the train, have branded eight specific vegetable oils the ‘Hateful Eight.’ Restaurants have begun replacing them with beef tallow. A significant portion of the American public has started avoiding them.
Here is what the research shows.
A comprehensive 2026 review in Critical Reviews in Food Science and Nutrition examined clinical and observational evidence on industrially produced seed oils and concluded that concerns about their health effects lack a scientific foundation.
A 2025 study presented at the American Society for Nutrition’s flagship conference, based on nearly 1,900 participants, found that higher linoleic acid in blood plasma — the primary omega-6 fatty acid in seed oils — was associated with lower levels of inflammatory biomarkers, not higher.
The 2026 clinical guide to cardiovascular nutritional controversies categorized seed oils as having evidence of benefit for cardiovascular outcomes and placed beef tallow in the evidence-of-harm category due to its association with increased LDL cholesterol.
Willett’s own position, stated in a December 2025 interview, is consistent with this body of evidence: the data does not support demonizing vegetable oils. The ‘compared to what?’ framework makes the point clearly. Replacing seed oils with butter or beef tallow replaces unsaturated fat with saturated fat. The evidence regarding that swap has been consistent for forty years and does not favour tallow.
The nuance in how the influencer conversation collapses is this: seed oils are widely used in ultra-processed foods — packaged snacks, fast food, ready meals — which are linked to poor health outcomes. The problem is the ultra-processed food, not the oil it contains. Correlation is not causation.
This is, incidentally, the same methodological error that drove the original anti-fat consensus of the 1980s. The wellness industry is now making the mirror-image mistake in the opposite direction.
—
The most directly relevant finding from Willett’s recent work for readers of The Long Ride is not about any individual food. It is about dietary patterns over time.
In March 2025, a paper co-authored by Willett and published in Nature Medicine examined midlife diets and 30-year health outcomes among more than 105,000 adults from the Nurses’ Health Study and the Health Professionals Follow-up Study.
The question was not which diet prevents a specific disease. Rather, it asked which midlife dietary patterns were associated with healthy aging — defined as reaching older age with physical capacity, cognitive function, and mental health intact.
The findings were consistent across the dietary patterns examined. Adults who ate more whole grains, legumes, vegetables, fruits, nuts, and healthy fats — and less red meat, ultra-processed food, added sugar, and refined starch — were significantly more likely to age well by every measure the study tracked. The Mediterranean diet and the MIND diet — a variant of the Mediterranean pattern specifically associated with brain health — showed the strongest associations with independent, cognitively intact aging.
The lead author noted an important point: there is no single diet that works for everyone. Healthy eating patterns can be adapted to fit individual needs, food preferences, cultural traditions, and health conditions.
The dietary patterns that predicted healthy aging were not identical across participants. What they shared were the same broad features: more plants, more fibre, more healthy fats, less processed food, and less added sugar.
That is not a new message. What is new is the size and duration of the evidence base supporting it. Thirty years. 105,000 people. Published in one of the most rigorous peer-reviewed medical journals. This is what the long game in nutrition science looks like.
—
One finding from Willett’s most recent work that I want to highlight specifically for this readership is on cognitive health.
A prospective cohort study in 2025, drawing on the Nurses’ Health Study and the Health Professionals Follow-up Study, examined associations between six healthy dietary patterns and subjective cognitive decline. The findings were consistent across patterns: adherence to healthy dietary patterns in midlife was associated with better cognitive function and lower rates of subjective cognitive decline in later life. The effect was not marginal. It was robust across the three cohorts examined.
Willett has spoken in recent interviews about his interest in understanding the long-term relationship between nutrition and cognitive and mental health — an area where cohort data has historically been sparser than cardiovascular data, but where findings are beginning to accumulate with increasing consistency. For adults in their sixties who are thinking seriously about brain health alongside cardiovascular health, this is the research frontier worth watching.
—
Here is what fifty years of Willett’s research adds up to:
Eat more plants. Eat more whole grains and less refined starch. Choose healthy fats — olive oil, nuts, fatty fish — over saturated fats, and don’t panic about seed oils. Eat less red meat and ultra-processed foods. Maintain a healthy weight. The specifics can be tailored to your preferences, culture, and health conditions. The broad pattern is consistent and well supported.
None of that is surprising. What is surprising is how persistently the wellness industry manages to make it complicated, frightening, and commercially useful. Every few years, a new villain emerges — fat, then carbs, then gluten, now seed oils. The villain changes, but the evidence underpinning Willett’s conclusions does not.
The most useful question you can ask about any nutritional claim you encounter is the one Willett has asked for fifty years: Compared to what? The answer to that question — not the headline, not the advertising, not the influencer’s before-and-after — is where the science lies.
Walter Willett’s book for general readers, Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating (Simon & Schuster), remains one of the most evidence-grounded nutrition books available and is worth reading in full. His research is freely accessible through Harvard T.H. Chan School of Public Health at hsph.harvard.edu.
Research & sources referenced in this piece
Tessier, A.J. et al. (2025). Optimal dietary patterns for healthy aging. Nature Medicine, published March 24, 2025. DOI: 10.1038/s41591-025-03570-5. Co-authored with Walter C. Willett.
Willett, W.C. (April 2025). Exclusive Interview: Unlocking the Secrets of Diet and Heart Disease. Vessel Plus. oaepublish.com
Willett, W.C. (December 2025). Food Truths from the World’s Top Nutrition Scientist. The Proof Podcast, Episode 393. theproof.com
Ludwig, D.S., Willett, W.C. & Putt, M.E. (2026). Concerns over conclusions in an ultra-processed food trial. Nature Medicine, 32(2), 463–464. DOI: 10.1038/s41591-025-04087-7
Carballo-Casla, A. et al. (2024). Dietary protein intake in midlife in relation to healthy aging — Nurses’ Health Study. American Journal of Clinical Nutrition, 119(2). DOI: 10.1016/j.ajcnut.2023.11.010
Liu, Y. et al. (2025). Dietary patterns and cognitive function — prospective cohort study from Nurses’ Health Study, NHS II, and Health Professionals Follow-Up Study. Data analyses performed September 2024 – November 2025.
Petersen, K.S. et al. (2026). Concerns about the health effects of industrially produced seed oils are without scientific foundation: a scoping narrative review. Critical Reviews in Food Science and Nutrition. DOI: 10.1080/10408398.2026.2657527
Maki, K.C. (2025). Linoleic acid and cardiometabolic risk biomarkers — study of nearly 1,900 participants. Presented at NUTRITION 2025, American Society for Nutrition, Orlando.
American College of Cardiology (2026). A Clinician’s Guide for Trending Cardiovascular Nutritional Controversies in 2026. PMC12914412.
Willett, W.C. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Simon & Schuster.
Willett, W.C. Nutritional Epidemiology, 3rd edition. Oxford University Press.
A singular American health anecdote alongside all this well-researched and rich data you've mined and parsed... I grew up in the 60s and 70s in a household whose kitchen was stocked with canned vegetables and soups; Screaming Yellow Zonkers, Ho-Hos, and Ding-Dongs; jello "salads"; and the emerging modern convenience of packaged quick meals like Hamburger Helper. Iceberg lettuce was our primary fresh food. From the time I started learning to cook at 7, I innately knew this was wrong, and was drawn to real, whole foods. I spent my babysitting money on fresh vegetables and fruit. Fortunately, by the time I was a teen I was allowed to cook most of our meals-- whatever I wanted if I provided a grocery list. Fast forward 50 years-- no blood pressure, heart disease, diabetes, or cholesterol pharmaceuticals. I've consistently maintained my high school weight. Most importantly, I feel about the same as I did when I was in my early forties. Essentially, I live like my grandparents did regarding diet, and it has mattered. These habits have successfully been transferred to my three children, who in their late 30s- mid 40s are quite healthy, too, and now down to grandchildren who cook alongside their mama.
A very interesting read and the logic of ‘compared to what’ is excellent. Something I’ve only realised recently and hit home particularly when looking at health was the line ‘the books were written to sell books. But the studies were written to find out.’