Jonathan is the author of the New York Times & USA Today Bestselling The Calorie Myth
Dr L: Is Protein Heart Healthy?
Jonathan: The Journal of the American Medical Association reviewed a whopping 147 studies on diet’s impact on health and found zero correlation between meat consumption and cardiovascular disease. [1] Further, distinguished researcher Dr. Halton at Harvard University found: “Exchange protein for carbohydrates [eating protein in place of carbs] has been shown to improve blood lipids [cholesterol], and in epidemiologic [observational] studies, higher protein diets have been associated with lower blood pressure and reduced risk of coronary heart disease.” [2]
Speaking about one of the world’s number one killers, cardiovascular disease, Chair of the Department of Nutrition at the Harvard School of Public Healthy, Dr. Willett, adds: “The Nurses’ Health Study is the only large prospective study to have examined the link between dietary protein and cardiovascular disease…The group of women who ate the most protein…were 25% less likely to have had a heart attack or to have died of heart disease than the women who ate the least protein…While this needs to be confirmed, it offers strong reassurance that eating a lot of protein doesn’t harm the heart.” [3]
Finally, when it comes to the health marker so many Americans take medication for, cholesterol, Harvard’s Dr. Willett continues: “Cutting back on carbohydrate and replacing those calories with protein lowers the levels of triglycerides that increase the risk of heart disease and also boosts HDL, the protective form of cholesterol.” [4]
Bottom Line: For a healthy heart, enjoy hearty servings of protein.
Dr L: Does Protein Cause Cancer?
Jonathan: A few years ago, a popular book and documentary claimed that protein causes cancer going so far as to assert that eating protein “turned cancer on,” while not eating protein “turned cancer off.” Let’s go back to our friends at the Harvard School of Public Health in the American Journal of Clinical Nutrition to see if this lines up with the findings of the broader research community. “A survey of 65 counties in rural China, however, did not find a clear association between animal product consumption and risk of heart disease or major cancers,” says Harvard’s Dr. Hu. [5] In fact, Dr. McCullough of the American Cancer Society remarks, “Fish and poultry have been associated with lower rates of coronary heart disease and cancer.” [6]
Bottom Line: No longer eating protein to avoid cancer is like no longer watering your garden helps you to avoid weeds.
Dr L: Does Protein Help Burn Body Fat?
Jonathan: One of the most fascinating types of nutritional studies is called isocaloric studies. In these studies, researchers give two groups of people the exact same number of calories, but vary the sources of calories. These studies consistently show that replacing calories from starches, sugars, or unnatural fats with the same number of calories from nutritious protein burns fat. Yes, you read that correctly. People eat the exact same number of calories, but burn body fat.
I know it sounds too good to be true, but going back to Dr. Halton at the Harvard Medical School: “Convincing evidence exists that protein exerts an increased thermic effect [calorie burning] effect when compared to fat and carbohydrate.” [7] University of Texas researcher Dr. Paddon-Jones continues to praise protein with: “There is a general consensus in the literature that protein stimulates dietary-induced thermogenesis [burning of calories] to a greater extent than other macronutrients.” [8] Finally, University of Washington’s Dr. Weigle concludes, “We found that an increase in dietary protein content comparable with that observed in popular low-carbohydrate diets, but [accompanied by] no reduction in dietary carbohydrate content, resulted in rapid losses of weight and body fat.” [9]
Bottom Line: Want to burn fat? Swap starches, sweets, and processed fats for protein.
Dr L: Is Protein Healthy Long Term?
Jonathan: Despite the fact that people have remained disease free across cultures and generations since our species started walking the earth, every few years low-protein fads flare up claiming long term health benefits. Ironically, when we look to proven research rather than observations or ideology, a much different conclusion becomes clear.
For instance, one of the top protein researchers in the world, Dr. Donald Layman at the University of Illinois, found that “During the past decade a growing body of research reveals that dietary protein intakes above the recommended daily allowance are beneficial in maintaining muscle function and mobility and in the treatment of diseases including obesity, osteoporosis, type 2 diabetes, metabolic syndrome, heart disease, and sarcopenia [age induced muscle tissue loss].” [10]
It’s important to note that these long-term health benefits also apply to animal sources of protein according to Dr. O’Keefe from the Mid America Heart Institute: “Diets high in lean protein can improve lipid [cholesterol] profiles and overall health…Lean animal protein eaten at regular intervals (with each meal) improves satiety levels, increases dietary thermogenesis [automatic calorie burning], improves insulin sensitivity, and thereby facilitates weight loss while providing many essential nutrients.” [11]
Bottom Line: Eating plenty of protein is part of living a long, healthy, and enjoyable life.
Dr L: Does Protein Help Prevent Overeating?
Jonathan: Starvation is not sustainable. Studies show that simply trying to eat less fails 95.4% of the time. Hunger isn’t healthy. We’re much more likely to lose weight and feel great if we change the quality of what we’re eating rather than cutting the quantity of what we’re eating. One of the most effective quality-based changes you can make to your lifestyle is enjoying more protein. In addition to all of the benefits already discussed, protein is more satisfying than either carbohydrate or fat, and therefore helps you to unconsciously avoid overeating.
For example, Dr. Blundell at the University of Leeds found that “Protein appears to be the macronutrient that suppresses energy intake to a greater extent than any of the other macronutrients.” [13] Similarly, Dr. Westerterp-Plantenga with Maastricht University discovered that “Protein is more satiating than carbohydrate and fat in the short term…and in the long term.” [12]
Bottom Line: Want to avoid overeating automatically? Eat more protein.
Dr L: Does Protein Does Harm the Kidneys, Liver, or Bones?
Jonathan: As you have seen, protein is a scientifically proven health and weight loss powerhouse. Despite this, and for completely unscientific reasons, you still may hear some individuals who are unfamiliar with modern nutritional research putting down protein for supposed harmful effects on your liver, kidneys, and bones. Don’t worry, the Harvard School of Public Health tells us, “there is little evidence that high protein diets pose a serious risk to kidney function in healthy populations.” [14] As for your lovey liver, “Simply stated, there is no scientific evidence whatsoever that high-protein intake has adverse effects on liver function,” says researcher Manninen with the University of Oulu [15]
Finally, when it comes to your beautiful bones, let’s go back to Dr. Westerterp-Plantenga at Maastricht University who tells us: “With respect to adverse effects, no protein-induced effects are observed on net bone balance or on calcium balance in young adults and elderly persons. Dietary protein even increases bone mineral mass and reduces incidence of osteoporotic fracture.” [16]
Bottom Line: If you ever worry about your kidneys, liver, and bones, remember that the only thing to fear about protein, is the fear of protein itself.
Dr L: Any Last Words on Protein?
Jonathan: When it comes to eating nutrient dense protein (humanely raised animals and wild seafood are the most concentrated sources), free yourself from misinformation, myths, and opinions, and enjoy simple slimness, proven science, and scrumptious protein
References:
Hu FB, Willett WC. Optimal diets for prevention of coronary heart disease. JAMA. 2002 Nov 27;288(20):2569-78. Review. PubMed PMID: 12444864.
Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004 Oct;23(5):373-85. Review. PubMed PMID: 15466943.
P.J. Skerrett, and Walter Willett. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Free Press Trade Pbk. Ed ed. New York City: Free Press, 2005. Print.
P.J. Skerrett, and Walter Willett. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Free Press Trade Pbk. Ed ed. New York City: Free Press, 2005. Print.
Hu, FB, and WC Willard. “Reply to TC Campbell.” Am J Clin Nutr 71 (2000): 850-51 (letter).
McCullough ML, Feskanich D, Stampfer MJ, Giovannucci EL, Rimm EB, Hu FB, Spiegelman D, Hunter DJ, Colditz GA, Willett WC. Diet quality and major chronic disease risk in men and women: moving toward improved dietary guidance. Am J Clin Nutr. 2002 Dec;76(6):1261-71. PubMed PMID: 12450892.
Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004 Oct;23(5):373-85. Review. PubMed PMID: 15466943.
Paddon-Jones D, Westman E, Mattes RD, Wolfe RR, Astrup A, Westerterp-Plantenga M. Protein, weight management, and satiety. Am J Clin Nutr. 2008 May;87(5):1558S-1561S. Review. PubMed PMID: 18469287.
Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, Purnell JQ. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005 Jul;82(1):41-8. PubMed PMID: 16002798.
Layman DK. Dietary Guidelines should reflect new understandings about adult protein needs. Nutr Metab (Lond). 2009 Mar 13;6:12. PubMed PMID: 19284668; PubMed Central PMCID: PMC2666737.
O’Keefe JH Jr, Cordain L. Cardiovascular disease resulting from a diet and lifestyle at odds with our Paleolithic genome: how to become a 21st-century hunter-gatherer. Mayo Clin Proc. 2004 Jan;79(1):101-8. Review. PubMed PMID: 14708953.
Westerterp-Plantenga MS. The significance of protein in food intake and body weight regulation. Curr Opin Clin Nutr Metab Care. 2003 Nov;6(6):635-8. Review. PubMed PMID: 14557793.
Blundell John E., Stubbs R. James. Diet Composition and the Control of Food Intake in Humans In: Bray GA, Couchard d, James WP, eds. Handbook of Obesity. New York: Marcel Dekker, 1997: 243-272.
Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004 Oct;23(5):373-85.Review. PubMed PMID: 15466943.
Manninen AH. High-protein weight loss diets and purported adverse effects: where is the evidence? Sports Nutr Rev J 2004; 1: 45-51.
Westerterp-Plantenga MS, Nieuwenhuizen A, Tomé D, Soenen S, Westerterp KR. Dietary protein, weight loss, and weight maintenance. Annu Rev Nutr. 2009;29:21-41. Review. PubMed PMID: 19400750.