Adults require about 0.8 or 0.9 grams of protein per healthy kilogram of bodyweight per day. Does it matter if that protein is from animals or plants? Apparently yes.
The adverse effects associated with long-term, high protein-high meat diets may include disorders of bone and calcium balance, increased cancer risk, disorders of the liver, and worsening of coronary artery disease.
What about our kidneys? Harvard University researchers followed thousands of healthy women for more than a decade to look for the presence of excess protein in their urine, a sign that kidneys may be starting to fail. The researchers found three dietary components associated with this sign of declining kidney function: animal protein, animal fat, and cholesterol. Each is found in only one place: animal products. No association was found between kidney function decline and intake of plant protein or fat.
High animal protein intake may induce hyperfiltration, a dramatic increase in the kidney’s workload. Within hours of consuming meat, whether beef, chicken, or fish, our kidneys may rev up into hyperfiltration mode, whereas an equivalent amount of plant protein causes virtually no such stress on the kidneys.
Animal protein consumption also appears to trigger the release of insulin-like growth factor 1 (IGF-1), a cancer-promoting growth hormone. IGF-1 levels rise during childhood to power our development and diminish when we reach adulthood. Should the levels remain too high, however, our cells will constantly receive a message to grow, divide, and keep going and growing. Not surprisingly then, the more IGF-1 in our bloodstream, the higher our risk for developing some cancers. Animal protein appears to stimulate IGF-1 production whether it’s the muscle proteins in meat, the egg-white protein in eggs, or the milk proteins in dairy. After just 11 days of cutting back on animal protein, however, our IGF-1 levels may drop by 20 percent.
Watching our animal-to-plant protein ratio may be useful for cancer prevention. The largest diet and bladder cancer study found that a 3 percent increase in animal protein consumption was associated with a 15 percent increased risk of bladder cancer, while a 2 percent increase in plant protein intake was associated with a 23 percent decreased cancer risk.
Dr. Ornish and colleagues were able to demonstrate that a nearly exclusively plant-based diet allowed for an apparent reversal in early stage cancer growth, so the ideal animal-to-plant protein ratio may be quite low.
The information on this page has been compiled from Dr. Greger’s research. Sources for each video listed can be found by going to the video’s page and clicking on the Sources Cited tab. References may also be found at the back of his books.
Image Credit: egal / Thinkstock. This image has been modified.
Popular Videos for Animal Protein
All Videos for Animal Protein
Fasting-Mimicking Diet Before and After Chemotherapy
How might we replicate the protective effects of fasting with food?
The Best Diet for Healthy Aging
Swapping just 1 percent of plant protein in place of animal protein was associated with signiﬁcantly less age-related deﬁcit accumulation.
How Big Meat Manipulated the Science
Big Meat downplays the magnitude of meat mortality.
Animal Protein vs. Plant-Based Protein
I discuss a public health case for modernizing the definition of protein quality.
Natural Dietary Treatments for Enlarged Prostate BPH
Cranberries and pumpkin seeds are put to the test for benign prostatic hypertrophy.
How to Boost FGF21 with Diet for Longevity
Fasting and exercise can boost the longevity hormone FGF21, but what can we eat—or avoid eating—to get similar effects?
How to Reduce the Glycemic Impact of Potatoes
Broccoli, vinegar, and lemon juice are put to the test to blunt the glycemic index of white potatoes.
How to Help Control Cancer Metastasis with Diet
Randomized controlled trials show lowering saturated fat intake can lead to improved breast cancer survival.
Preventing Inflammatory Bowel Disease with Diet
Eating a diet filled with animal products can disrupt your microbiome faster than taking an antibiotic.
The Health Effects of Mycoprotein (Quorn) Products vs. BCAAs in Meat
Clinical trials on Quorn show that it can improve satiety and help people control cholesterol, blood sugar, and insulin levels.