Scientific research continues to show consuming red and processed meats or a high-animal protein diet has a profoundly damaging effect on overall health and longevity. It is vitally important that red 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. 

Long-term studies

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 from all causes over the follow-up period would change if some of the animal protein sources (equivalent to 3 percent of total daily calories) were replaced with plant protein sources:

• Replace processed red meat: 34 percent decrease in risk
• Replace unprocessed red meat: 12 percent decrease in risk
• Replace poultry: 6 percent decrease in risk
• Replace fish: 6 percent decrease in risk
• Replace eggs: 19 percent decrease in risk
• Replace dairy: 8 percent decrease in risk3

Higher intake of plant protein sources is 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 control for potential confounding factors and detect 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:

• High animal protein intake excessively elevates insulin-like growth factor 1 (IGF-1), which promotes cancer development. (14-18) 
• Research on nutrient-sensing pathways that respond to protein intake suggests reducing essential amino acid intake (i.e. reducing animal protein) promotes longevity. (19) (Note that the elderly require more protein than younger adults. (20, 21))
• The pro-inflammatory effects of dietary saturated animal fats. (22-25)
• The pro-oxidant and pro-inflammatory properties of excess heme iron. (26, 27)
• Cooking-produced carcinogens in meats, such as heterocyclic amines and polycyclic aromatic hydrocarbons. (28-31)
• Genotoxic N-nitroso compounds produced from processed meats. (30-33)
• Detrimental effects of carnitine and choline on the gut microbiome that promote inflammation. (34-37)

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:

• Measured after a single meal, butter impaired vascular function compared to nuts and other predominantly unsaturated plant fats. (38)
• A study comparing Atkins, South Beach, and Ornish weight maintenance diets (all with the same calorie counts) assigned participants to each diet for four weeks each. At the end of the Atkins diet phase, LDL cholesterol was higher and vascular function lower compared to the other diets. (39) 
• Participants (who lived at the study site during the study) were fed 420 g red meat or a vegetarian meal daily for 15 days, with the rest of their diets kept exactly the same. Stool samples and colon cells collected after 10 days on each diet showed an increase in production of carcinogenic N-nitroso compounds during the red meat diet compared to the vegetarian diet, and an increase in N-nitroso compounds binding to DNA in colon cells (which leads to DNA damage and colon cancer). (40)
• A study comparing about two servings daily of fiber-rich whole grains to red meat for three weeks each suggested the whole grain diet improved gut microbiome diversity compared to the red meat diet. Body fat mass was also lower after the whole grain intervention. (41)
• After four weeks, a diet containing red meat increased production of the pro-inflammatory compound TMAO, compared to white meat and vegetarian diets. (36)

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.

Joel Fuhrman, MD is a board-certified family physician specializing in nutritional medicine. He is President of the Nutritional Research Foundation and the author of 7 New York Times bestselling books, including his most recent book, “Eat to Live”. Visit his website, DrFuhrman.com.

👉👉Get $10 off $150 or more on Dr. Fuhrman’s website. Use coupon LS10OFF150.

Originally posted on DrFuhrman.com. Reprinted with permission.

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