Although research recommends a high-protein diet for building muscle mass and preserving muscle mass during fat loss, we must consider the potentially detrimental effects of a high-protein diet to our health.
Many vegans associate a high-protein diet with poor health, and for good reason. According to Harvard Medical School, health conditions linked to a high-protein diet include the development of high cholesterol, a higher risk of cardiovascular disease, weight gain, increased cancer risk, and kidney disease.
These concerns are valid, but they are specific to a high animal protein diet, not a high plant protein diet.
high cholesterol and heart disease
By definition, a vegan diet is cholesterol-free. There is zero dietary cholesterol in plant foods. As such, plant-based diets have been proven to lead to a significant drop in blood cholesterol, thereby reducing the risk of our number one killer, heart disease (1).
And even though your body needs cholesterol to form hormones and digest fat-soluble vitamins, your body can produce all the cholesterol it needs from raw materials such as fat, sugars, and proteins. You do not need to consume dietary cholesterol.
Furthermore, a 2010 meta-analysis conducted by the Physician’s Committee for Responsible Medicine confirmed that a low-fat, plant-based diet substantially reduces cardiovascular disease risk (2).
Weight gain
Concerning weight gain, over a hundred years of metabolic research has proven that energy balance is the basic mechanism that regulates weight gain and loss (3). A high-protein diet in and of itself has no impact on weight regulation. The only way you will gain weight following a high-protein diet is if the extra protein calories you consume put you into a caloric surplus.
Cancer
In the NIH-AARP (The National Institutes of Health - American Association of Retired Persons) Diet and Health Study, the most rigorous study of diet and mortality ever conducted, researchers observed the diets of 500,000 men and women over a period of 10 years (4). After compiling their data, the researchers came to a simple conclusion: Meat consumption is associated with an increased risk of dying from cancer, dying from heart disease, and dying prematurely in general.
This conclusion was made after controlling for other diet and lifestyle factors, thereby excluding the possibility that people who ate meat also smoked more, exercised less, or failed to eat their fruits and vegetables.
The researchers hypothesized that heme iron, which is the iron found in blood and muscle, is largely to blame. Heme iron generates cancer-causing free radicals and has been linked to heart disease (5). Plant foods contain all the iron you need in the form of non-heme iron, which doesn’t generate the same cancer-causing free radicals that heme iron does. Furthermore, phytonutrients and phytates in plant foods have been proven to slow down and even stop cancer cell growth (6, 7).
Kidney disease
Regarding kidney disease, high animal-protein intake can have a profound negative influence on normal kidney function by inducing a state called hyperfiltration, which causes a dramatic increase in the workload of the kidneys.
Now, this isn’t such a bad thing if it happens occasionally. If you have healthy kidneys, you already have quite a bit of built-in reserve kidney function, which is why you can live with only one kidney. But if you consume animal products, you are constantly forcing your kidneys to call upon their reserves, which taxes your kidneys over time.
In 1987, researchers first discovered a correlation between those who eat a plant-based diet and better kidney function (8). They first theorized that this was due to plant-based eaters consuming less protein overall. However, more recent research has proven that your kidneys appear to handle plant protein very differently from animal protein.
Within just hours of consuming meat, your kidneys are forced into hyperfiltration mode, whereas consuming an equivalent amount of plant protein causes no observable stress on the kidneys (9, 10). In fact, consuming tuna fish can cause your kidney filtration rate to jump up 36.3% within three hours, but consuming an equivalent amount of protein from tofu places zero strain on the kidneys (11).
A 2014 study from the Chinese University of Hong Kong analyzed the effects of soy protein versus dairy protein consumption on the kidney function of 270 female subjects with diseased kidneys (12). The researchers found that the soy protein helped preserve kidney function.
Then why is plant protein beneficial to kidney function while animal protein is detrimental? Because animal protein causes inflammation.
In fact, in a study conducted at the University of Internal Medicine in Italy, researchers found that their subject’s hyperfiltration response to animal protein disappeared when they administered a powerful anti-inflammatory drug along with a meat-based meal (13). So if you want to have healthy kidneys, you can either follow a vegan diet or take anti-inflammatory drugs every time you eat animal products.
In conclusion, decades of research have clearly established that a high-protein vegan diet does not contribute to high cholesterol, cardiovascular disease, weight gain, cancer risk, or kidney disease.
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Your vegan fitness trainer,
Leif