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Protein is an integral part of our diet. It is a necessary component to almost all factors of living. However, its implications for our health are frequently misunderstood.

Recently I spoke to Dr. Donald Layman about some of the health implications of protein. Dr. Layman holds a Ph.D. in nutrition and runs a large lab at the University of Illinois’ nutrition Ph.D. program. This lab and Dr. Layman’s research primarily focus on a multiplicity of topics regarding protein and amino acids, including their role in human health. He definitely can be considered the go-to guy when it comes to questions concerning protein.

Dr. Donald Layman

My first question to Dr. Layman was predicated on his research (1) which showed that a protein intake at higher levels than the current RDA (Recommended Daily Allowance), which is 0.8 grams per kilogram of body weight, improved various health markers.

Daniel: What exactly is wrong with the current RDA for protein? What would be the health implications of raising it?

Donald: I actually think that the RDA is okay. However, it is being misused. The definition of the RDA is the minimum intake to prevent a deficiency. Thus, as far as we can see, people in the U.S. that meet the RDA do not exhibit symptoms of protein deficiencies such as edema (2), fatty liver (3), hair/nail loss (4), loss of muscle mass (5), and increased bone weakness (6). Nevertheless, that is not the same thing as saying that the RDA is set up for optimal health. There is a range of good nutrition for any nutrient versus merely filling in the gaps of potential deficiencies. For instance, 60 mg of vitamin C will prevent scurvy, but people regularly take 500–1000mg to improve immunity and prevent colds. For protein, we misuse the RDA because it is perceived as the optimal amount for health when in reality, it is the minimal amount to offset decisively. There is a lot of evidence for healthy adults that twice the RDA is actually the optimal level for health and, in particular, muscular health. The reason for this is that as we age, the signaling elements for muscle protein synthesis [i.e., protein being produced to repair muscle damage] shift from (when we are young) being driven by hormones too (when we are older) being driven by dietary protein and in particular the quality and quantity of dietary protein. This shift is primarily explained evolutionarily.

Daniel: What is (or, what should be) the role of protein in weight loss/management?

Protein has a hugely important role to play in weight loss and muscle gain. This is because they are inseparable assets in both processes.

Donald: One of the first roles protein has in weight loss is the contribution to weight loss and a change in body composition. For instance, a person going from 300 lbs to 175 lbs but still having a high level of body fat at 175 lbs, such a weight shift did not make that person healthier, as that indicates the loss of lean body mass. If you starve yourself or go on a low-calorie, low-protein diet, you will lose fat and lean mass at a 1:1 ratio which is profoundly antithetical to optimal health. However, if you reduce your calories and increase your protein, you can shift that proportion of weight loss almost exclusively to fat. Exercise will do the same thing. Ideally, weight loss should increase in exercise, an increase in protein, and a reduction in calories. By doing this, you will lose nothing but body fat and, in turn, become healthier. A higher intake of protein also increases thermogenesis [i.e., the process by which the body burns calories to produce heat]. For instance, to compare protein with carbohydrates, there is a 15% increase in calories burned per calories consumed from protein. Hence, a higher protein diet will allow you to eat more calories and still lose weight. Protein is also very satiating, allowing someone who is trying to lose weight to feel fuller on a low-calorie intake.

Daniel: What is the importance of protein in treating certain diseases/conditions like diabetes, cardiovascular disease, and obesity?

Donald: When it comes to obesity, its role is primarily in its efficacy in a weight loss plan, as we just discussed. This relates to diabetes because obesity and diabetes very often run parallel. What we know about diabetes is that it is a problem of excess blood sugar. Glucose is actually highly toxic to the body, so it is kept within very narrow ranges. Diabetes exceeds these ranges. One way to correct this is to lower your carbohydrate intake to roughly 140 grams of carbohydrates per day or lower. One of the easiest ways to do this is by increasing your protein. There have been multiple studies with early diagnosed diabetics, where people have a higher protein intake (1.5–1.6 grams per kg per day) and low carbohydrate intake. There is an immediate correction of virtually all the problems of metabolic syndrome. Obesity and diabetes are major complications that are major risk factors for cardiovascular disease, but the cardiovascular disease has two tracts. One is driven primarily by triglycerides (diabetes). The other is driven by LDL cholesterol. Lower carbohydrates and higher protein definitely correct the triglyceride aspect of cardiovascular disease. The LDL portion is more commonly genetically based. Things like statins are the best way to correct this. However, the primary dietary cause of an increase in LDL is insulin. If you lower insulin, you can lower LDL also. When it comes to this side of the cardiovascular disease spectrum, a high-protein diet will be of little use. In any case, excess calories and a sedentary lifestyle are almost causal routes to obesity, which drastically increases one’s risk for diabetes, which is the main cause of cardiovascular disease. A higher protein intake allows people to control their calories, which is ultimately a great baseline scenario for preventative purposes. People often try to make saturated fat, cholesterol, sugar, salt, or any other individual factor out to be at the top of the list when it comes to the cause of these conditions when excess calories are the real risk factor. Given that protein can help people get their calories under control, helping them improve their body composition, a high protein diet is a useful tool in the prevention of these metabolic diseases/conditions.

The overarching narrative to extract from this interview is that protein is an integral part of your health. Therefore, eating a higher protein diet should be a staple in one’s weight loss journey and aspirations in attaining better overall health. Including high protein sources in one’s diet, such as eggs, dairy, and fish, will ultimately be positive in its impact on your health. If you want to calculate your calories and daily protein needs, here’s a useful calculator.

Citations:

1. Layman, Donald K. “Dietary Guidelines should reflect new understandings about adult protein needs.” Nutrition & metabolism vol. 6 12. 13 Mar. 2009, doi:10.1186/1743–7075–6–12

2. Coulthard, Malcolm G. “Oedema in kwashiorkor is caused by hypoalbuminemia.” Pediatrics and international child health vol. 35,2 (2015): 83–9. doi:10.1179/2046905514Y.0000000154

3. Asha Badaloo, Marvin Reid, Deanne Soares, Terrence Forrester, Farook Jahoor, Relation between liver fat content and the rate of VLDL apolipoprotein B-100 synthesis in children with protein-energy malnutrition, The American Journal of Clinical Nutrition, Volume 81, Issue 5, May 2005, Pages 1126–1132, https://doi.org/10.1093/ajcn/81.5.1126

4. Rushton DH. “Nutritional factors and hair loss.” Clinical and Experimental Dermatology. Jul 2002.

5. Campbell, Wayne W et al. “Dietary protein adequacy and lower body versus whole body resistive training in older humans.” The Journal of physiology vol. 542,Pt 2 (2002): 631–42. doi:10.1113/jphysiol.2002.020685.

6. Jane E. Kerstetter, Kimberly O. O’Brien, Karl L. Insogna, Low Protein Intake: The Impact on Calcium and Bone Homeostasis in Humans, The Journal of Nutrition, Volume 133, Issue 3, March 2003, Pages 855S–861S, https://doi.org/10.1093/jn/133.3.855S