A study published in the journal of Cell Metabolism last month (March 4, 2014) found that diets consisting of moderate to high protein in adults over the age of 50 to be associated with increased diabetes-related mortality. This study was reported on in the Wall Street Journal under the title of "The Risk of High-Protein Diets" and also found that adults aged 50-65 who reported moderate to high protein intake had an increase in cancer deaths. However, the study also found that in those older than age 65, the same moderate or high protein intake was associated with lower cancer deaths. With regard to cardiovascular mortality (heart disease), reported moderate or high protein intake was associated with lower mortality in both age groups. The Wall Street Journal report lead many of my patients to question their protein intake and inquire whether protein as a macronutrient should be reduced in their own diets.
The most concise answer that I can give to this type of question is it depends on your present state of health, as well as the distribution of total calories consumed between protein, fat, and carbohydrates.
The data compiled in the recent study is scattered in its relevance, based on age, and does not provide any concrete evidence of health concerns due to high-protein diets. As a physician who has spent close to 20 years helping people lose weight for the primary purpose of health improvement, this new study is concerning and deserves attention. In my practice, protein plays a large role in helping people lose weight. Additionally, it should not be lost that countless studies have proven time and time again that being overweight increases your risk of diabetes, heart disease and cancer.
Further analysis of this study shows it to have flaws, like many health-related studies, that should be taken into account when drawing broad conclusions such as those put forth by the study authors, and reported in the Wall Street Journal. The data used in the Cell Metabolism study is based on a self-reported study that asked 6,000 adults over 50 to cite an average day of their diet, and then subsequently tracked them through 18 years, with no follow-up dietary questions. Essentially, the method used to glean the information upon which the cautionary headlines about protein have been drawn was a one-time questionnaire and a follow up to assess health outcomes 18 years later. The authors clearly state in the study's limitations that this could result in less-than-accurate data collection. While this may be the only feasible way of conducting such a study and receiving as many results, we must question the sheer validity.
Another important limitation I found while looking at the study's participants as a whole is that the group reported eating 1,823 calories a day; 51 percent of the calories were from carbohydrates, 33 percent of the calories were from fat and 16 percent of the calories were from protein. This would support an under-reporting of food intake, which mirrors what is seen in clinical practice. Since the calorie count is lower than expected, based on many additional studies, the actual protein, carbohydrate and fat recorded could also be skewed. This is a threat to the internal validity of the study and questions the foundation upon which its conclusions are based.
In the study, researchers did an analysis that controlled for reported animal-based protein intake and the cancer mortality was eliminated or significantly reduced, but the same was not seen when plant protein intake was controlled for. The researchers stated this indicates that the animal proteins promote cancer mortality and not that plant-based proteins have a protective effect. Several studies have shown that red meat and processed meat intake is associated with increased cancer risk, especially colorectal cancer. Other studies show that cooking red meat at high heats increases the creation of carcinogens, but this is not found when cooking poultry or fish at high heats. In this study there was no analysis done to separate red meat from leaner animal protein sources such as poultry and fish, which raises the question of whether the conclusion that animal proteins as a total category lead to higher rates of cancer mortality is accurate. We simply do not know to what extent those who reported moderate to high protein intake chose red meat or other animal protein sources.
What do we know about protein?
Given the potential questions of validity in the recent study's conclusions, let's turn our focus back on what we actually know about protein. We know that protein plays a large role in weight loss, weight maintenance and an overall healthy lifestyle. From my research, and over 20 years of practicing bariatric medicine, I have also found that most of my patients struggling with weight and medical conditions do not eat enough protein, or importantly spread protein intake appropriately throughout the day for ideal utilization of important amino acids. In my practice, 89 percent of my patients have signs of Metabolism Dysfunction, one of the primary contributors to the medical condition that causes the majority of mortality in the United States. The biggest threats that patients face with Metabolism Dysfunction are heart disease, high blood pressure, stroke, diabetes, obesity, dementia and many types of cancer.
Correcting metabolism dysfunction is quite often the means to the end in helping my patients lose weight, and protein plays a key part in this process. I recommend a dietary plan that includes 25-30 grams of protein at each and every meal, as well as snacks rich in 10-15 grams of protein. By the standards of the recent Cell Metabolism study, that would be regarded as a high-protein diet.
Protein is helpful in correcting Metabolism Dysfunction because it does not signal the same type of rapid insulin release as carbohydrates do. I find that meals or snacks consisting of primarily carbohydrates tend to cause blood sugar to rise too quickly and then fall too rapidly in my patients with Metabolic Dysfunction. This rapid rise and fall produces a hunger that is not like typical hunger. Symptoms such as feeling weak and shaky, headachy or significant irritability are often present. My patients feel they need to eat and eat fast. Usually the types of food they reach for are more carbohydrates or sugars which only lead to further hunger and the net effect of more calories consumed over the course of the day. This dietary plan for metabolism correction with the regular intake of lean protein, along with a balance of complex carbohydrates and healthy fats helps in reducing body fat and reducing the risk factors for obesity-related diseases. This begs the question: How is it possible that in one study, moderate to high protein intake was linked to increased diabetes mortality as well as an increased rate of cancer mortality in certain groups, but not others, when in regular interactions and follow ups with my patients, it reduces both across all age groups?
Where do we go from here?
So after all this, where am I with my dietary recommendations for my patients for weight loss and weight maintenance afterward? I find it is most critical for overall improved health, to correct the metabolic dysfunction that makes weight gain so easy and weight loss so challenging. That involves the intake of a lower calorie diet that contains adequate lean protein, controlled carbohydrate and controlled fat intake. Lean protein means poultry, fish, low fat dairy, vegetable sources such as non-GMO soy or pea based protein powders and limited red meat. I will still recommend the intake of animal-based protein in the weight loss process because of the balance of higher protein coupled with the lower carbohydrate content level it contains compared to vegetarian based dishes such as beans and rice, which have three or four times as much carbohydrate content as protein. In the weight loss process, controlling carbohydrate intake is critical to reverse the physical symptoms of hunger and sweet cravings that sabotage sincere willpower.
Metabolic dysfunction is treatable and reversible with the metabolism correcting diet and weight loss. Once metabolic dysfunction resolves, my patients still need lean protein but can replace animal based proteins with more vegetarian options because their tolerance for carbohydrates has increased with correcting the metabolic dysfunction. We can look at lab work today and see improvements in blood sugar, cholesterol levels, triglycerides that equate with better long term health. We can see improvements in body composition testing which shows loss of body fat, decreased readings on the scale and a smaller waist circumference that we know is also associated with improved health outcomes. To date, there are not markers in lab testing that show our future risk of cancer mortality. To stack the odds in my patient's favor, I recommend correcting the metabolic abnormalities we know are associated with diabetes, cardiovascular disease and many cancers, and then transition this successful meal plan to one that incorporates more non-GMO vegetarian protein and less animal protein for long term weight maintenance.