More than a century ago, The New York Times reported on an ambitious cancer study of its era, involving nearly 4,600 cases tracked over seven years. Even then, researchers suspected that the increasing consumption of animal-based foods was contributing to the rising tide of cancer cases. Fast-forward to today, and that early suspicion has been largely confirmed by modern science. Comprehensive meta-analyses now show that mortality from all causes — including heart disease, stroke, and cancer — tends to be lower in people consuming more plant-based diets. Added to that are lower rates of type 2 diabetes and obesity.
What makes these findings even more compelling is that many participants in these studies didn’t adopt plant-based eating until relatively late in life. Yet despite decades of exposure to risky dietary habits, they still saw substantial reductions in chronic disease risk within just a few years of dietary change.
One of the landmark studies, the Adventist Health Study-2, involving over 96,000 participants, showed that even those who had been consuming meat for most of their lives saw measurable benefits in longevity and chronic disease reduction after switching to more plant-centered eating. This was true across demographics: whether participants were under or over 60, slim or overweight, past smokers or lifelong non-smokers, the results were consistent — shifting toward plant-based eating was linked to better health outcomes.
The biology behind this is clear. Many cancers, for example, can take decades to develop, with early mutations accumulating over time before turning into clinical disease. This explains why, when populations transition from traditional, mostly plant-based diets to Westernised, animal-heavy diets, cancer rates can take 20 or more years to surge. For instance, as Japan and Korea adopted Western food patterns, dramatic increases were recorded in breast, prostate, and colorectal cancers. Mortality from breast cancer in Japan, for example, followed an almost vertical trajectory once Western diets took hold.
We see similar patterns in migration studies. Rural Chinese men moving to the United States experience a dramatic rise in cancer risk, not because of genetics, but largely because of adopting the standard Western dietary pattern, high in saturated fats, animal protein, refined carbs, and processed foods. However, despite a lifetime of dietary risks, adopting healthier patterns, even late, can slow or even reverse some of this risk.
And what about heart disease? Multiple recent trials — including the PREDIMED study on Mediterranean diets and interventions like the Portfolio Diet — show that plant-heavy dietary patterns can start improving cardiovascular markers like LDL cholesterol, blood pressure, and inflammation in just weeks or months, reducing heart disease risk in measurable ways over time.
So, does this mean everyone should go completely vegetarian or vegan? Not necessarily. Recent analyses like the 2019 Global Burden of Disease study and trials such as the UK Biobank cohort confirm that the greatest benefits come not simply from avoiding animal foods but from actively consuming more whole plant foods. These include fruits, vegetables, whole grains, legumes (like lentils and chickpeas), nuts, and seeds.
One major study published in JAMA Internal Medicine found that even those who only cut down on red and processed meat saw significant reductions in cancer and cardiovascular mortality, regardless of whether they fully adopted a vegetarian diet. And while vegetarian and vegan diets may offer additional advantages, flexitarian or semi-vegetarian approaches (where meat is consumed occasionally) still appear to reduce risk compared to heavy meat consumption.
What virtually all modern nutrition authorities now agree on is this: avoid ultra-processed foods, minimise saturated animal fats, and eat more plants. Whether it’s the Mediterranean diet, the DASH diet, vegetarian, or predominantly plant-based omnivorous eating, the shared denominator in all successful, disease-reducing diets is a rich intake of whole plant foods.
❝ The debate should no longer be about which healthy diet is “best,” but rather how we can help individuals move away from the aggressive marketing and availability of ultra-processed junk and toward food choices that nourish long-term health. ❞
It’s never too late to make that shift. Even after a lifetime of poor eating, the human body has remarkable resilience. Within months, markers of inflammation and disease risk can begin to improve, and within years, the risk of major diseases like heart disease, diabetes, and cancer can drop substantially. Longevity is not determined by the first half of life alone — what you do now still matters profoundly.
As the old saying goes, “The best time to plant a tree was 20 years ago. The second-best time is today.” The same is true of your health.m”’
References:
• Satija, A., et al. “Plant-Based Diets and Risk of Cardiovascular Disease: A Review.” JAMA Cardiology, 2019.
• Adventist Health Study-2 (AHS-2). Multiple publications, Loma Linda University.
• Global Burden of Disease Study 2019. Lancet.
• EPIC-Oxford Study.
• PREDIMED Trial. New England Journal of Medicine, 2018.
• Sinha, R., et al. “Meat Intake and Mortality.” Arch Intern Med., 2009.
• Orlich MJ et al. “Vegetarian Dietary Patterns and Mortality.” JAMA Internal Medicine, 2013.
Give a Reply