The "carnivore diet" aka carnivore diet? What do scientific studies say about this topic?

Having looked at what the carnivore diet actually is in the first part of this series of articles, in this second part we will start to take a closer look at the benefits claimed by supporters of this diet and try to assess what the reality is based on scientific research.

What are the benefits of the carnivore diet?

Advocates of the carnivore diet say that it can do many things, including the following:

• Cause weight loss
• Improve cardiovascular health
• Reduce inflammation
• Increase testosterone levels
• Prevent nutrient deficiencies

Let's examine these claims with a healthy dose of science:

Weight loss

Here are a few of the most scientifically proven ways to achieve weight loss without counting calories:

• Eat more protein
• Drink more water with meals (6)
• Limit the foods you eat (7)
• Eat less oil, refined flour and sugar (8)
• Eat higher-volume foods (9) that require longer chewing (10)

And that's a perfect summary of the Carnivore Diet.

For starters, it includes a large amount of protein - 200 to 300 grams per day for many people - and if you've ever eaten large amounts of protein, then you know how effective this is when it comes to reducing appetite.

In addition, it's not unusual to eat two to four pounds of meat per day during this diet. Since meat is 70% water, this results in significant additional water consumption per day - and the fact that it is consumed with food enhances its satiating effect (6).

The carnivore diet is also very restrictive, which is an effective way to suppress appetite and reduce calorie intake. The fact that the carnivore diet eliminates all the highly processed foods that many people eat too much of - bread, sweets, ice cream, cakes, pizza and the like - makes this diet even more effective in this regard.

Finally, meat takes up more space in the stomach than other foods and needs to be chewed well, both of which can improve satiety and suppress appetite.

It is therefore not surprising that many people have lost enormous amounts of weight on the carnivore diet, particularly during the first few weeks when the body excretes water and breaks down glycogen in response to the carbohydrate restriction (11, 12).

However, it should be noted that the same results can be achieved with any high-protein, low-carbohydrate diet (13-15).

In other words, there is nothing really special or unique about the carnivore diet in terms of weight loss.

"But the insulin!" I hear the fanatical hordes of cannibals grumble. "This diet keeps the insulin under control!"

Ah yes, insulin, the metabolic villain of the hour, supposedly responsible for all kinds of metabolic disorders.

As for the Carnivore Diet, many people claim that it is superior to other forms of low-carb diets because it keeps insulin levels as low as possible, which in return is supposed to speed up fat loss.

And then there's the reality.

For one thing, protein-rich foods also raise insulin levels - just as much as carbohydrate-rich foods (17). Whey protein, for example, raises insulin levels more than white bread (18) and beef raises insulin levels more than brown rice (19).

Some say that the insulin response to protein-rich foods like whey protein and beef is slower (as if that's better), but this is wrong. Protein-rich foods, just like carbohydrate-rich foods, cause a rapid rise in insulin levels (19), followed by a rapid drop.

Even if following the carnivore diet kept insulin levels lower than other forms of low-carb diets, this would not guarantee fat loss.

As long as calorie intake is the same, people will lose equal amounts of fat regardless of what happens to insulin levels or how their bodies respond to them (20). Even giving overweight people medication to lower insulin levels does not cause fat loss (21, 22).

So the bottom line is that the carnivore diet can help you lose weight - but no better than any other type of diet that makes you eat fewer calories than you consume over time.

Cardiovascular health

One of the main reasons that various health organizations recommend limiting meat consumption is to reduce the risk of cardiovascular disease. Animal products contain a lot of saturated fat and cholesterol and it is believed that both of these compounds can increase the risk of cardiovascular disease.

If you are not familiar with these two compounds, it is worth noting that saturated fat is the type of dietary fat that is solid at room temperature and that cholesterol is a pale, waxy substance that is chemically similar to dietary fat. Cholesterol is present in cells of the body and is used to make hormones, vitamin D and chemicals that help digest food.

A few decades ago, it was believed that foods such as eggs and meat containing cholesterol increased the risk of heart disease. Today we know that it's not quite that simple.

Eggs have been more or less rehabilitated (23) and scientific research shows that processed meat can be linked to a higher incidence of heart disease (24), but this does not apply to red meat.

It would be premature to say that cholesterol-rich foods do not play a role in heart disease (25), but most experts agree that eating cholesterol-rich foods does not significantly increase the risk of heart disease.

On the other hand, many foods that are high in cholesterol also contain large amounts of saturated fat, which is more of a concern.

The long-held view that saturated fats increase the risk of heart disease has been challenged by recent research (26), which many people who follow the carnivore diet are happy to throw around to prove that they are right and the establishment and naysayers are wrong.

The problem, however, is that these studies have been seriously criticized by well-known nutrition and cardiac researchers for several weaknesses, omissions and limitations (27, 28).

These scientists insist that there is a strong link between high saturated fat intake and heart disease (29) and that we should follow the generally accepted dietary guidelines for saturated fat consumption (30) (less than 10% of daily calorie intake) until we know more.

To put this into perspective, let's say you eat 2500 kcal per day, then your daily upper limit for saturated fat would be 30 grams.

If you follow a normal, balanced diet, then it's easy to stay below this threshold. To reach this limit, you would need to eat 150 grams of full-fat cheese, 20 strips of bacon or three large cheeseburgers per day.

However, if you follow the Carnivore Diet, you can easily exceed this upper limit on a regular basis.

For example, here is the nutritional content of 900 grams of ribeye steak, a fattier type of beef that is a staple in the diet of many carnivore dieters:

• 1,535 kcal
• 182 grams of protein
• 10 grams of carbohydrates
• 85 grams of fat
• 33 grams of saturated fat

As you can see, 20% of the total calories from ribeye steaks are made up of saturated fat and some meats contain even more saturated fat.

This is the reason why the consumption of saturated fat in people following the carnivore diet is often double the recommended amount.

In defense of this practice, these people often point to primitive peoples such as the Masai in Africa, and the Inuit in Alaska, Canada and Greenland, who are known to eat a lot of meat and saturated fats and are seen as paragons of health.

Such claims do not stand up to closer scientific scrutiny.

An early study conducted by scientists at Vanderbilt Medical School showed that the Maasai in Africa had fewer markers of heart disease based on blood cholesterol levels and tests of heart function (31).

The scientists were not able to accurately record or control what these tribesmen ate, but they assumed that many of their calories came from whole milk, which is rich in saturated fat - and not from meat, which they ate only five times a month.

The same scientists performed autopsies on the hearts of 50 Maasai tribesmen over the course of a decade and found that these people suffered from severe arteriosclerosis (a hardening and thickening of the arteries) similar to what is found in people who follow a Western diet (32).

As for the Inuit, research conducted by scientists at the National Institute of Public Health found that the rate of heart disease in these people was similar or even higher than in the average American (33).

In addition to this, none of these ethnic groups really follow a true carnivorous diet. The Maasai have a high carbohydrate intake from cow's milk (34) and the Inuit have between 8 and 54% of their calories from carbohydrates (35).

The bottom line is that there is little data to tell us how the carnivore diet affects the risk of heart disease over time.

Having said that, we can only laugh at some anecdotal reports from Dr. (or no longer Dr.) Shawn Baker, who shared his blood work with the rest of the world in a podcast interview with Robb Wolf (36).

After following the Carnivore Diet for over a year, here's what those numbers looked like:

• His total cholesterol level was 205, which puts him in the "intermediate risk" category for heart disease.
• His HDL cholesterol level (the good cholesterol) was 44, which also falls into the "medium risk" category and is only 4 points above the high risk category.
• His fasting blood glucose level - also a risk factor for heart disease (37) - was 127. A fasting blood glucose level considered healthy is 100 or below, and the American Diabetes Society considers anything above 127 to be a sign of diabetes (38).
• His total testosterone level was 237, which is less than half of what is considered normal for people in their early fifties (39) and low enough to be classified as low testosterone (40). Low testosterone levels are also a risk factor for heart disease (41) and diabetes (42).
• His vitamin D blood level was 30, which, depending on who you ask, is pretty close to deficient (43). Low vitamin D levels are also a risk for heart disease (44).

In other words, his levels were modest to say the least.

To justify these levels, Baker claimed that such things are normal in athletes like him. However, even though there is evidence that some athletes have higher fasting blood glucose levels than sedentary people (45), I know of nothing to justify the high cholesterol levels, low HDL levels, low testosterone levels, and low vitamin D levels.

In addition, Baker said that his low testosterone levels could be with healthy downregulation in response to increased sensitivity at the cellular level. In other words, since his body is more responsive to testosterone (or not), it must not be producing as much testosterone.

Where is the evidence for this, you may ask. Who knows? Who cares...

And then, of course, there's the inconvenient fact that an overwhelming amount of research shows that eating fruits and vegetables reduces the risk of heart disease, and that not eating these foods increases that risk.

For example, a study conducted by scientists at the University of Nis came to the following conclusion (46):

Those in the top tercile of fruit consumption (> 5 pieces of fruit per day) had a lower risk of heart disease compared to those in the lowest tercile ( Another study, conducted by scientists at the Norwegian University of Science and Technology, found a strong correlation between low fruit and vegetable consumption and heart disease, cancer and overall mortality risk (47).These results have been confirmed by a number of other studies (48, 49, 50).

The conclusion is that the carnivore diet is likely to increase the risk of heart disease according to current expert opinion and a large number of studies.

Inflammation

The term inflammation is an ambiguous umbrella term for many undesirable physical symptoms and according to many followers of the carnivore diet, consuming large amounts of meat reduces inflammation.

Technically, inflammation is a prolonged activation of the immune system and is usually measured by looking at the levels of different chemicals in the body such as C-reactive protein and cytokines.

Scientific research shows that chronically high levels of these biomarkers are associated with various disease states including obesity and cancer (51, 52), so it is reasonable to take steps to reduce these levels.

As evidence that the carnivore diet is ideal for fighting inflammation, its proponents often point to a study conducted by researchers at Boston University on 55 overweight men (53).

The scientists divided the subjects into two groups:

1. Group one consumed a diet that provided 55% of calories in the form of fat, 35% of calories in the form of protein and 10% of calories in the form of carbohydrates.
2. Group two consumed a diet that provided 25% of calories in the form of fat, 15% of calories in the form of protein and 60% of calories in the form of carbohydrates.

These diets were designed to allow both groups to lose one pound of weight per week over a 12-week period, and the scientists measured blood levels of C-reactive protein at the beginning and end of the study.

After 12 weeks, a 30% reduction in C-reactive protein levels was observed in group 1, while only a 3% reduction was observed in group 2.

Carnivore supporters interpret this result to mean that

less carbohydrates = less inflammation = better health

but there is more to the study than meets the eye.

First of all, the low-carb group ate more than twice as much protein - as is the case in many other studies that "prove" that low-carb diets are better than high-carb diets. This makes it impossible to say whether the benefits were due to a reduction in carbohydrate intake or an increase in protein intake.

Second, the dietary control in this study was very loose, so it may be possible that the group that ate more carbohydrates also ate more refined flour and sugar, which could have increased levels of C-reactive protein (54).

Third, the group that followed the high-carbohydrate diet curiously showed better levels of other blood markers, which included a greater reduction in total cholesterol levels and LDL cholesterol levels, so it is impossible for us to know which group would be healthier in the long run.

Another statement on inflammation that is worth addressing is the claim that plants can cause inflammation.

There is evidence that some people have negative reactions to certain foods (55), which may include certain types of carbohydrates such as grains, dairy products and even certain fruits, and that people suffering from autoimmune diseases may benefit from avoiding gluten (56).

However, there is little evidence that any of these reactions can cause inflammation or that eating only meat is the optimal solution.

The bottom line is that any claims that the carnivore diet reduces inflammation are based more on wishful thinking and deliberate misinterpretation than hard facts.

In the third part of this article series, we will look at the alleged positive effects of the carnivore diet on testosterone levels and take a closer look at the issue of nutrient deficiencies before coming to a final assessment of this nutritional approach.

https://www.muscleforlife.com/carnivore-diet/

By: Michael Matthews