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High Protein Diets? Yeah or Nay

Here's what the research brought to us this week in my nutrition class on:

As a long time vegetarian, turned vegan I get the protein question all the time! How do you get your protein? I wasn’t educated enough at 14 to know and probably ate terribly until my 30’s when I started to pay attention. I ate a lot of legumes and fish at the time. But it wasn’t until I turned 40 that I had quit fish and found tofu. Now, I also learned that vegetables contain protein and quinoa is high in protein, so it’s not just soy products and legumes for me. Currently there is a trend in the United States to be vegan… or rather eat a vegan diet, because living a Vegan lifestyle is another thing entirely.

I would like to address these questions from my personal knowledge first before diving into the research. High Protein diets may benefit some due to health reasons, but high protein diets are not for everyone. Especially when the protein comes from known sources like red meat, that cause health issues. Honestly you should be eating more vegetables than anything else. The USDA finally caught on with that.

Ok, let’s see what the research says:

“Lifespan and metabolic health are influenced by dietary nutrients. Recent studies show that a reduced protein intake or low-protein/high-carbohydrate diet plays a critical role in longevity/metabolic health. Additionally, specific amino acids (AAs), including methionine or branched-chain AAs (BCAAs), are associated with the regulation of lifespan/ageing and metabolism through multiple mechanisms. Therefore, methionine or BCAAs restriction may lead to the benefits on longevity/metabolic health. Moreover, epidemiological studies show that a high intake of animal protein, particularly red meat, which contains high levels of methionine and BCAAs, may be related to the promotion of age-related diseases. Therefore, a low animal protein diet, particularly a diet low in red meat, may provide health benefits. However, malnutrition, including sarcopenia/frailty due to inadequate protein intake, is harmful to longevity/metabolic health.” (Kitada, Ogura, Monno, Koya, 2019).

Ok, so there is one protein, red meat, as it states here it’s related to diseases. But what is also pointed out here is that malnutrition is possible due to inadequate protein intake. Do I believe there is malnutrition in this country, yes. I think it’s a socioeconomic class issue and also happens with the elderly.

Now, the implications of a high protein diet, but also how it might be beneficial.

“Long-term consumption of a high-protein diet could be linked with metabolic and clinical problems, such as loss of bone mass and renal dysfunction. However, although it is well accepted that a high-protein diet may be detrimental to individuals with existing kidney dysfunction, there is little evidence that high protein intake is dangerous for healthy individuals. High-protein meals and foods are thought to have a greater satiating effect than high-carbohydrate or high-fat meals. The effect of high-protein diets on the modulation of satiety involves multiple metabolic pathways. Protein intake induces complex signals, with peptide hormones being released from the gastrointestinal tract and blood amino acids and derived metabolites being released in the blood. Protein intake also stimulates metabolic hormones that communicate information about energy status to the brain. Long-term ingestion of high amounts of protein seems to decrease food intake, body weight, and body adiposity in many well-documented studies. The aim of this article is to provide an extensive overview of the efficacy of high protein consumption in weight loss and maintenance, as well as the potential consequences in human health of long-term intake.”

“High-protein diets may be appropriate for some individuals, but not for others; hence, specific individual needs, as well as potential negative consequences, must be considered cautiously before such a diet is adopted. The protein content of a diet may be measured using several methods; however, because of the great individual variability in caloric requirements, measuring intake based on the proportion of proteins in total energy intake seems to be the most realistic method. A moderate intake of 1.5 g/(kg $ d) may be easily included in the acceptable protein intake range (AMDR 10–35%) for most individuals.” (Cuenca-Sánchez, Orenes-Piñero, & Navas-Carrillo, 2015).

“It is also important to note that high-protein diets are harmful to CKD patients; however, for healthy kidney patients, in view of the findings of several studies, the consumption of a high-protein diet appears to be more advantageous than deleterious. In addition, dietary protein seems to play an important role in other metabolic processes, such as satiety cellular signaling, and thermogenic and glycemic regulation in the body. However, this effect becomes important only when consumption is above the RDI; thus, it seems likely that protein intake above the RDI could be advantageous in many situations.” (Cuenca-Sánchez, et al. 2015).

“While some cohort studies have shown increased risk of CVD amongst meat eaters compared with vegetarians or low meat eaters, controlling for the wide range of potential confounders is difficult. Although recent studies have attempted to investigate the specific effects of unprocessed and processed meats on CVD risk, these have provided conflicting results and further research is needed to clarify matters. While meat products are a significant contributor to SFA and sodium intakes, unprocessed lean red meat has a relatively low SFA and sodium content. Intervention studies have indeed demonstrated favourable effects of lean red meat on traditional CVD risk factor such as blood cholesterol levels and blood pressure. Recent research has, however, suggested that a high consumption of processed meat may increase the risk of developing type 2 diabetes but further research is needed to determine the level of intake associated with higher risk and whether it is the meat per se in these products or other ingredients such as pastry or additives used. Several studies have shown meat eaters to have a higher BMI compared with vegetarians, but it is impossible to attribute this to any individual lifestyle or dietary factor because vegetarians tend to be more health conscious.” (Wyness, Weichselbaum, O’Connor, et al. 2011).

What this last paragraph tells me is that more research is needed. Maybe a lean cut of red meat is ok for you to eat, but I still believe in moderation. I also believe in knowing where the meat came from to be sure that it was free from antibiotics and other things but that’s a topic for another day and another reason I am staying a vegan plant based eater. I also don’t think we have seen the full effects of people who are partaking in the Keto diet just yet.


Wyness L, Weichselbaum E, O’Connor A, et al. Red meat in the diet: an update. Nutrition Bulletin. 2011;36(1):34-77. doi:10.1111/j.1467-3010.2010.01871.x.

Cuenca-Sánchez, M., Orenes-Piñero, E., & Navas-Carrillo, D. (2015). Controversies surrounding high-protein diet intake: Satiating effect and kidney and bone health. Advances in Nutrition, 3, 260.

Kitada M, Ogura Y, Monno I, Koya D. The impact of dietary protein intake on longevity and metabolic health. EBioMedicine. 2019;43:632-640. doi:10.1016/j.ebiom.2019.04.005.

2. A mother brings her 16-year-old daughter in for nutritional advice. The girl states that she is considering becoming a vegetarian because she has heard that it is a much healthier lifestyle. What nutrition guidance should be provided to ensure that she is adequately informed and will receive adequate amounts of protein in her diet?

Holy moly is this question for me or what. Now, I was 14 and lived in a house with a bodybuilder who dieted off and on all year. But my mom never went to see anyone about getting me educated. Had she, my life may have turned out differently. Fortunately, I was never completely diagnosed with any health complications that could not be corrected. But if I was presented with this situation I would and could be completely honest with her about what it means to go vegetarian in a world full of meat eaters and how hard it might be at times to find foods that are nutritious.

“Vegetarianism is typically defined as the practice of abstaining from the consumption of meat, animal flesh, or animal slaughter by-product [1–4]. Typically, a vegetarian is someone who lives on a diet of grains, pulses, legumes, nuts, seeds, vegetables, fruits, tubers, fungi, algae, and/or other non-animal based foods (e.g., salt) with, or without dairy products, honey and/or eggs [1]. There are variations of the diet such as a semi-, pesco-, lacto-ovo-, lacto-, ovo-, and vegan diets depending on whether a minimal amount of meat, fish, eggs, dairy, or honey is included in the definition of the vegetarian diet. The term flexitarian describes the voluntary reduction in excessive meat consumption [5]. At the restrictive end of the vegetarian spectrum, a vegan diet excludes all animal products including meat, fish, poultry, insects, gelatin, shellfish, eggs, dairy, and honey. In order to distinguish between healthful and unhealthful vegan diets that majorly include refined and processed foods, the term whole food, plant-based diet was developed by Dr. T. Colin Campbell in the early 1980s. The current definition of a plant-based diet is one that consists of all minimally processed fruits, vegetables, whole grains, legumes, nuts, seeds, herbs, and spices and excludes all animal products, including red meat, fish, poultry, eggs, and dairy products [6]. The spectrum of vegan diets is considered by many to be extreme and includes a raw-food vegan diet that has the same exclusions as veganism with the additional exclusion of all foods cooked at temperatures greater than 48 °C (see Table 1) [7].” (Rocha, Laster, Parag, Shah, 2019)

So I was a pesco, lacto-ovo, vegetarian for a long time. But, educating my client on the different diets available to her may also help her in making a good choice. So I would first provide information, but then it would be also important to address the potential health risks:

“According to the American Dietetic Association, a wellplanned vegetarian diet can meet the current recommendations of all nutrients [14]. However, definitions of the vegetarian diet vary with interpretation and depending on the types and amounts of foods actually consumed it is possible for a nutritional deficiency to occur. The nutrient deficiencies to consider in a vegetarian diet include protein, omega-3 fatty acids, vitamin D, vitamin B12, iron, calcium, and zinc. In the systemic review by Kwok et al., there was an overall majority benefit of vegetarian dietary components in reducing cardiovascular disease and mortality; however, there was an increased relative risk of harm associated with the consumption of tinned fruit [36]. This is one example of how food processing, i.e., canning, can turn a traditionally healthy food into an unhealthy food.” (Rocha, et al., 2019)

“Despite concern for protein deficiency even among vegetarians, adequate amounts of protein (0.8 g/kg body weight/day) can be consumed in a sole plant-based diet, as seen in approximately 1.5 billion vegetarians in the world [9, 39]. However, a detailed nutrition history should be obtained to assure consumption of all essential amino acids. For example, a diet high in corn, nuts, and cereals and lower in legumes could result in a lysine deficiency. This can be easily overcome, however, with increased consumption of beans, peas, or lentils [13]. Examples of complementary proteins in the vegetarian diet include food pairings of vegetables and whole grains, seeds and whole grains, seeds and nuts, legumes and whole grains, legumes and nuts, legumes and seeds, legumes and dairy, dairy and nuts, dairy and seeds, or dairy and whole grains.”(Rocha, et al., 2019)

“Vegetarian sources of dietary vitamin D include ultraviolet light-exposed yeast and mushrooms, and fortified foods such as milk, orange juice, breakfast cereals, and margarine.”

Deficiencies in B12, Iron, Calcium, Zinc are possible and would need to be checked.

Once I reviewed and informed my client and after she made her decision on which diet to follow, I would help her formulate a meal plan that she could sustain taking into account all her activities. If she was in sports she may need a higher calorie meal plan than if she was not. If she was unsure how to prepare foods, I would share recipes and food preparation information. I have had to learn all of this on my own. I will be happy to share this information with a client in the future.


Rocha JP, Laster J, Parag B, Shah NU. Multiple Health Benefits and Minimal Risks Associated with Vegetarian Diets. Current Nutrition Reports. 2019;8(4):374. doi:10.1007/s13668-019-00298-w.

Thank you for reading,


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