Scientific research continues to show consuming red and processed meats or a high-animal protein diet has a profound damaging effects on overall health and longevity. It is vitally important that meat in our diet should be replaced (or at least greatly limited) in favor of foods that are proven to offer protection against cancer – such as green vegetables, berries, beans, nuts and seeds. This should not be seen as controversial and is supported by an overwhelming amount of data.
Large, long-term studies investigating intakes of animal and plant protein with regard to mortality have consistently concluded that more plant protein and less animal protein is linked to a longer life.1-4 Studies consistently link greater red meat consumption to a greater risk of premature death.5-7 Here’s an example:
A 2016 study published in JAMA Internal Medicine investigated the relationship between animal vs. plant protein sources and mortality risk from almost 30 years of follow-up from the Nurses’ Health Study and Health Professionals Follow-up Study. Together, these two studies included over 170,000 participants.
Interesting findings came out of one particular question the researchers asked:
What would happen if the participants replaced some of their animal protein with plant protein?
They analyzed the data to estimate how participants’ risk of death would change from all causes over the follow-up period if some of the animal protein sources (equivalent to 3 percent of total daily calories) were replaced with plant protein sources:
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Higher intake of plant protein sources are associated with better health: for example, seeds and nuts reduce the risk of cardiovascular disease and are linked to longevity, and micronutrient and fiber-rich beans are linked to improved blood pressure, LDL cholesterol, body weight, insulin sensitivity and enhanced lifespan.4, 8-13
Prospective cohort studies are observational and cannot prove causality, but these studies are crucial to our understanding of health and longevity, because heart disease and cancer – our two biggest killers – develop over the course of multiple decades, not just a few months. Studies that follow tens of thousands of people for 10 or 20 years or more, and evaluate hard endpoints (death, heart attack, stroke, cancer, etc.) provide valuable insights into the habits that may promote or prevent these diseases. The significance of findings from observational studies is supported by laboratory studies showing there are plausible mechanisms for the association – good reasons why it’s not just a random correlation, but likely a causal relationship.
Many meat-centered diet proponents dismiss these important studies out of hand, ignoring the careful collection of data and complex mathematical analysis by skilled epidemiologists that controls for potential confounding factors and detects potentially significant associations.
The correlations between animal protein intake and all-cause mortality in long-term prospective studies are consistent with other observational studies on specific diseases, and are backed up by laboratory studies that have uncovered the plausible cellular and molecular mechanisms behind the correlations:
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Although eating a keto or carnivores’ diet can lower blood sugar and promote weight loss in the short term, the long-term effects of a diet so high in animal products (according to the preponderance of evidence) is damaging over the long term. That is why I reiterated that it is important to see the long-term studies with hard endpoints. Looking at short-term weight loss studies will lead you on a path to damage your potential for optimal longevity.
Although the disease-promoting effects take many years to build up, several short-term studies point to the beginnings of the damage of a high-animal product diet:
Meat-heavy diets get one important thing right: They cut out weight gain-promoting, disease-promoting high-glycemic refined carbohydrates. But large amounts of animal products are unquestionably disease-promoting, too. The Nutritarian diet does more than just restrict one type of harmful food. It limits or completely avoids all other disease-promoting foods and focuses heavily on foods that are richest in protective nutrients and are linked in scientific studies most consistently to a lower risk of cardiovascular disease, cancer, and other chronic diseases.
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Huang J, Liao LM, Weinstein SJ, et al. Association Between Plant and Animal Protein Intake and Overall and Cause-Specific Mortality. JAMA Intern Med 2020. doi: 10.1001/jamainternmed.2020.2790
Song M, Fung TT, Hu FB, et al. Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality. JAMA Intern Med 2016, 176:1453-1463. doi: 10.1001/jamainternmed.2016.4182
Tharrey M, Mariotti F, Mashchak A, et al. Patterns of plant and animal protein intake are strongly associated with cardiovascular mortality: the Adventist Health Study-2 cohort. Int J Epidemiol 2018. doi: 10.1093/ije/dyy030
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Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
For over 30 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.
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