Ivor Cummins posted a link to this on Twitter. It's by Dr. Garth Davis.
"Ok, get ready for a very long rant, but this is the most important rant I have ever made.
On the last post I stated that meat causes diabetes. Many responses question the science so I will now present you with an EXTENSIVE review of the research. It is important to understand that this statement is not based on just one study but rather many. It is also important to understand that this statement is based on intensive epidemiological study AND randomized control trials. If you want science, here it is in extensive detail but explained in a narrative.
I hate to steal the thunder from my upcoming book but I can think of no more important an item to be discussed now. We are in a growing epidemic of diabetes and somehow we think we should treat it with high protein diets, which are likely the reason we are developing diabetes to begin with.
Meat consumption is a major cause of diabetes, carbs are not. I know, that is a bold statement. I would not have believed it myself several years ago. In fact, the president of The American Society of Bariatric Physicians doesn’t seem to know this, as he actually stated at a recent meeting that we should be telling our patients not to eat fruits for fear of the carbs. Even the American Diabetes Association diet suggests meat be part of the diet, and has patients counting carbs.
I found this out quite unexpectedly. I was studying the health of the Japanese because, while we are one of the most unhealthy cultures, the Japanese appear to be a very healthy people. I was most interested in the fact that they eat a very carb heavy diet, with lots of white rice. At the time, I believed carbs caused diabetes, so I figured that the Japanese where somehow genetically resistant to diabetes. Interestingly, however, I found that the Japanese have recently had a dramatic increase in diabetes, from 9.9% in 1997 to 15.3% in 2007. Certainly lower than our 20-30%, but the rapid growth is concerning. In fact, the Japanese government was very concerned. The Ministry of Health and Labor and Welfare studied this issue and noted that the Japanese diet is rapidly changing and becoming more westernized. They specifically point out that the increase in meat consumption and the decrease in fruits and vegetables may be the major factor behind the rise in diabetes {Morimoto, 2010 #772}.
As I continued to research, it became readily apparent that the Japanese do not have a genetic resistance to diabetes, and may actually be genetically susceptible. An excellent study was performed in Brazil looking at Brazilian born Japanese and comparing them to previous generations that had immigrated. They found that second generation Brazilian born Japanese had extremely high rates of diabetes, especially when compared to prior generations {
http://www.ncbi.nlm.nih.gov/pubmed/12488952}. The picture became even more clear when I learned that Brazil has one of the highest consumption rates of animal protein. In fact, the Brazilian government has been responding to the excessive meat consumption by releasing suggestions to the public to specifically limit meat intake {
http://www.ncbi.nlm.nih.gov/pubmed/22894818}.
Of course, this is a simple correlation. There can be many other factors that caused the relation. If meat truly has a causative role in the development of diabetes then there would need to be a serious epidemiologic study that shows this correlation while controlling for possible confounding factors. More importantly, one study would not do. There would have to be multiple studies that draw the same correlation after extensive statistical analysis.
The first place I looked was the EPIC study. The EPIC (European Prospective Investigation Into Cancer and Nutrition) study is one of the largest prospective cohort studies that have ever been done looking at the relationship between nutrition and disease. They have followed 521,000 people recruited from 10 European countries. They have hundreds of top scientists that have used specialized food assessment tools to get a better understanding of how the food people eat affects the likelihood of them developing disease. Indeed, after looking at thousands of people and following for 12 years, the scientists concluded that meat, and especially processed meat (bacon, lunch meats, etc), is significantly associated with the development of type 2 diabetes, and fruits and vegetables are associated with a decrease in diabetes development {
http://www.ncbi.nlm.nih.gov/pubmed/22983636}{
http://www.ncbi.nlm.nih.gov/pubmed/24196190}. The craziest finding in the EPIC data analysis was the fact that glucose and fructose consumption was actually correlated with LESS diabetes. Many authors, like Robert Lustig, have talked at length about the harms of fructose. Lustig makes these claims largely based on rat studies and overfeeding studies, but in this very well done epidemiological study, looking at real people, if you replace just 5% of the saturated fats in your diet with fructose (presumably from fruits) you reduce your risk of developing diabetes by a whopping 30% {
http://www.ncbi.nlm.nih.gov/pubmed/23880355}. This goes against everything you hear about diet in America, but just how great is our diet working for us? We are currently in a diabetes epidemic, and the affected people are trying to eat more meat and actually cutting out fruit to cut back carbs. Are they doing any better? I can tell you that, from what I see in my office, certainly not.
Now before all the naysayers start screaming that correlation does not equal causation, lets look if this correlation also holds true in America. One of the most fascinating groups to follow is the Seventh Day Adventists in Loma Linda, California. They are fascinating because the religion basically holds that you should treat your body as a temple. Therefore, as a whole, they are very healthy. They do not drink or smoke, they exercise moderately, and they strive to eat healthy. Interestingly, many of them believe that we should not eat animals. Of course, the interpretation of what to eat varies and we therefore get an interesting mix of meat eaters, fish eaters, vegetarians who consume dairy, and vegans. This fairly homogenous group of people living in a similar area with similar habits but different dietary practices makes for a perfect group to study. In fact, the Adventist Health Studies have done just that. They have prospectively followed thousands of Adventists for many years and released many papers. Like the EPIC study they found that animal protein was significantly associated with diabetes. It is quite interesting to note that they found a graduated increase in the risk of developing diabetes depending on the amount of animal protein consumed. Vegans had an extremely low development of diabetes of only 2.9% while vegetarians had 3.2%, pescatarians had 4.8% and meat eaters had a 7.6%. That is a low rate for meat eaters compared to the public, but the Adventists tend to not consume as large a quantity of meat, even if not vegetarian. They did note that weekly consumption of meat over a 17 year period increased the risk of developing diabetes by a whopping 74% over vegetarians {
http://www.ncbi.nlm.nih.gov/pubmed/19351712}, {
http://www.ncbi.nlm.nih.gov/pubmed/21411506}, {
http://www.ncbi.nlm.nih.gov/pubmed/3046303}, {
http://www.ncbi.nlm.nih.gov/pubmed/18349528}. This correlation held true even when controlling for weight, which is surprising given vegans weigh less than meat eaters. So controlling for weight means basically just looking at lighter, healthier meat eaters. Yet meat still correlated with diabetes even if not overweight.
Amongst the largest epidemiologic studies in America are the Nurses Healthy study and Health Professions Follow Up Study done by Harvard. There are 2 Nurses Health study. The original started in 1976 and prospectively followed up 122,000 nurses. The second has followed 116,000 nurses since 1989. The Health Profession Follow Up Study has followed 51,000 male health care professionals since 1986. So what did these studies show about the relationship between meat consumption and diabetes? Once again, there was a significant association between meat, processed meat, and development of Type 2 diabetes. In fact, increasing meat consumption by just ½ serving a day increased risk of developing diabetes by 48% {
http://www.ncbi.nlm.nih.gov/pubmed/15534160}, {
http://www.ncbi.nlm.nih.gov/pubmed/23779232}, {
http://www.ncbi.nlm.nih.gov/pubmed/21831992} {
http://www.ncbi.nlm.nih.gov/pubmed/24284436} {
http://www.ncbi.nlm.nih.gov/pubmed/11874924} .
The Women’s Health Initiative looked at 37,000 women over 8 yrs and again showed correlation between animal protein consumption and diabetes, especially the good old all American hot dog and bacon {
http://www.ncbi.nlm.nih.gov/pubmed/15333470}. Like the EPIC study, they also found that sugar was not related to the development of diabetes at all {
http://www.ncbi.nlm.nih.gov/pubmed/12663565}.
There are many epidemiologic studies from around the world that further confirm this correlation, as well as many that show that plant based diets protect against diabetes {
http://www.ncbi.nlm.nih.gov/pubmed/19662376}, {
http://www.ncbi.nlm.nih.gov/pubmed/24523914}. I do not know of a single study showing that people who eat meat are protected from diabetes. Correlation does not equal causation, but you have to admit that this data is certainly compelling, and where there is this much smoke there must be fire.
So what is causing diabetes? Well, let me start the story by looking at a documentary done by the BBC. They looked at a set of 35 year old twins who went on separate diets for a month. One went on a very low carb diet and one went on a very low fat diet. In the end the low carb brother complained of being constipated, having brain fog, and not having much energy. He did lose more weight but much of it was water weight. Most interestingly the very low carb brother showed increasing fasting blood sugars. This seemed to shock them as they thought that eliminating carbs would improve insulin sensitivity, but in fact it does not.
The reason is complex but let me see if I can simplify. Our bodies are literally designed to live on sugar. Each cell generates energy by taking in sugar and turning it into energy via a pathway called the Krebs cycle. Whether by divine design or by evolution, we are literally created to process sugar and starch. Insulin is essential to get the sugar into the cell. Yes, we have an emergency pathway for energy if sugar is not available, but we most efficiently function using carbs. It is our brain and body’s primary fuel. I find it ludicrous that people claim that insulin is an evil villain. Why in the world would we evolve such an efficient system that has worked forever? Why would we have insulin in our body to begin with? The craziest thing is that writers, like Robert Lustig and Gary Taubes, who demonize insulin, then suggest patients should eat protein to avoid insulin secretion. Ironically, they seem to have missed the science that shows that animal protein actually causes disproportionately high insulin secretion. Beef actually raises insulin more than pasta {
http://www.ncbi.nlm.nih.gov/pubmed/9356547}.
The problem is not insulin or sugar per se, it is the cells ability to respond to insulin. This is called insulin resistance. The muscle in the body is the greatest consumer of sugar and therefore the site where insulin must work effectively to remain healthy. With a high protein diet you are stimulating insulin. Insulin also has an effect where it prevents break down of fat. If you eat meat, the insulin stimulated will cause the fat, which is consumed with the protein, to be stored in the muscle cells. If you eat an apple or a potato, there is insulin secretion but no fat to be placed into the muscle cell {
http://www.ncbi.nlm.nih.gov/pubmed/9516198} {
http://www.ncbi.nlm.nih.gov/pubmed/15356006}, {
http://www.ncbi.nlm.nih.gov/pubmed/19026935}, {
http://www.ncbi.nlm.nih.gov/pubmed/22185843}.
One of the main factors causing fat to be collected in the muscle is inflammation {
http://www.ncbi.nlm.nih.gov/pubmed/21862724} {
http://www.ncbi.nlm.nih.gov/pubmed/15836891}. Inflammation causes damage to the muscle cells that result in the accumulation of fat. One of the critical changes that have occurred over the years is that we have evolved away from the bicarbonate producing diet of our ancestors to a modern day, higher protein, acidic diet. Our increased protein consumption leads to increased intake of amino acids rich in sulfur {
http://www.ncbi.nlm.nih.gov/pubmed/12450898}. The resulting acidosis leads to disease by inciting inflammation, causing leaching of calcium from muscle cells to buffer the acid, muscle wasting, and causing fat deposition in the muscle cells {
http://www.ncbi.nlm.nih.gov/pubmed/21481501} {
http://www.ncbi.nlm.nih.gov/pubmed/23841017} {
http://www.ncbi.nlm.nih.gov/pubmed/21352078} {
http://www.ncbi.nlm.nih.gov/pubmed/11842945} {
http://www.ncbi.nlm.nih.gov/pubmed/24232975}. Gary Taubes, the hero of the high protein/low carb movement, recently published his labs in order to show that his lipids are within normal range. Not being a doctor he obviously did not pay attention to the fact that his bicarbonate level was a very low 17 which means he is in a state of acidosis and slowly but steadily hurting his body and creating inflammation and disease.
Eating meat also causes inflammation because animals are rather dirty. You almost have to wear a hazmat suit to handle a raw piece of chicken because of fear of getting a bacterial infection like salmonella. Cooking will kill the bacteria but it does not destroy the endotoxin produced by the bacteria which is embedded in the muscle(protein) of the animal. When we consume meat, the saturated fat causes the endotoxin to be absorbed into the body and our immune system sets off a state of inflammation {
http://www.ncbi.nlm.nih.gov/pubmed/17991637} {
http://www.ncbi.nlm.nih.gov/pubmed/19755625}. The inflammation leads, again, to fat deposition in the muscle cell.
Finally, stress hormones certainly contribute to high sugars and inflammation. There was a study that is often cited by people advocating a high protein diet. The study took 21 overweight adolescents and had them do 3 different diets, each for 1 month. They ate the same amount of calories in each diet but one was high protein/low carb, one was low glycemic index, and one was low fat. I think the authors wanted to show better weight loss with low carb but no such luck. They did note, however, that the metabolic rate dropped the least with the high protein diet and that became their conclusion in the Journal of the American Medical Association. This was met with all kinds of fanfare by the high protein advocates, but what they failed to see is that, in the study, the high protein group had very high levels of cortisol in their urine and higher levels of C reactive protein, which is a measure of inflammation. Cortisol is a stress hormone that counters insulin’s effect and raises blood sugar, and is an independent risk factor for diabetes and heart disease {
http://www.ncbi.nlm.nih.gov/pubmed/20660036} {
http://www.ncbi.nlm.nih.gov/pubmed/17370058} {
http://www.ncbi.nlm.nih.gov/pubmed/20739384}. C reactive protein, due to it significance as a sign of inflammation, has been independently associated with diabetes {
http://www.ncbi.nlm.nih.gov/pubmed/14988310} {
http://www.ncbi.nlm.nih.gov/pubmed/17696726}. So while they were celebrating the short term slightly better metabolic rate, they missed the fact that the patient was in inflammation that will lead to fat deposition in the muscle and eventual insulin resistance {
http://www.ncbi.nlm.nih.gov/pubmed/22735432}.
Once fat gets inside the muscle cells it interferes with the muscle cell’s ability to develop insulin receptors. With less insulin receptors it becomes more difficult to get sugar into the cell for processing, and the sugar then builds up in the blood. The pancreas then has to churn out even more insulin just to get the sugar into the cells. The very high insulin, which is not normal, will cause even more fat to enter the cells in a vicious cycle.
Combine this with the fact that iron in the meat causes oxidation, which affects the pancreas’ ability to secrete insulin, and now you have full blown diabetes with high sugars. Meat eaters tend to have higher iron stores which are directly correlated with diabetes formation {
http://www.ncbi.nlm.nih.gov/pubmed/23046549} {
http://www.ncbi.nlm.nih.gov/pubmed/14871914} {
http://www.ncbi.nlm.nih.gov/pubmed/1317328} {
http://www.ncbi.nlm.nih.gov/pubmed/23866833}. In fact, simply drawing large amounts of blood out of a diabetic does appear to improve insulin resistance just by reducing the iron {
http://www.ncbi.nlm.nih.gov/pubmed/11591239}. Of course, I think it would be easier to just avoid the steak.
I should note that there is much disagreement at what comes first, the chicken or the egg, ie insulin resistance or insulin hypersecretion. I would note that those who believe that it is hypersecretion first believe it is from reactive oxygen species, created during consumption of meat, and iron, ingested with the consumption of meat.
So, I hope you can see that the high sugars that define diabetes are not, in fact, the cause of diabetes. Rather, the high blood sugars are an after effect, a symptom. The problem is actually the fat and inflammation that is destroying the body’s ability to utilize the sugar.
The interesting thing is that people talk about carbs, and specifically wheat, causing inflammation. However, if you actually take a group of people and feed them a high fat meal vs a high carb meal, the high fat meal develops significantly increased inflammation after the meal, the carbs do not {
http://www.ncbi.nlm.nih.gov/pubmed/12499333} ,
http://www.ncbi.nlm.nih.gov/pubmed/14668275, {
http://www.ncbi.nlm.nih.gov/pubmed/16219650} {
http://www.ncbi.nlm.nih.gov/pubmed/20067961}. The craziest study I have seen is one where they gave a group of people 1.5 liters a day of sugary drinks and compared them to a group drinking 1.5 liters of artificially sweetened drinks. As would be expected, the sugary drink group consumed more calories and therefore gained more weight. Interestingly, even though they gained weight, they did not show any signs of increasing inflammation {
http://www.ncbi.nlm.nih.gov/pubmed/16087988}.
Study after study has shown that people eating fruits, veggies, and especially grains, exhibit remarkably low levels of inflammation. Not only do they have low levels of inflammation but they also have considerably low levels of diabetes. Numerous studies looking at carb and grain intake confirm that the more carbs you eat the less inflammation, and consequently, the less diabetes risk you have {Valachovicová, 2006 #197}, {Cozma, 2012 #775}, {Rankin, 2007 #734}, {Montonen, 2013 #759}, {Barbaresko, 2013 #760}, {Ye, 2012 #762}, {Muraki, 2013 #480}, {Gao, 2004 #242}, {Galland, 2010 #84}, {Ford, 2001 #241}, {Cooper, 2012 #781}, {Brunzell, 1971 #822}, {Christensen, 2013 #821}.
I have shown you epidemiologic data and studies looking at individual lab values. I have used logic that says, “meat causes inflammation, and inflammation causes diabetes, so meat must cause diabetes”. Certainly the preponderance of evidence points to this effect, but the gold standard in research is the randomized control trial that specifically compares a diet heavy with animal protein compared to a diet without animal protein. Studies on rats have shown that high protein, high fat, and specifically diets that produce ketosis, lead to inflammation and insulin resistance {Flanagan, 2008 #746} {Jornayvaz, 2010 #233}, but we really need to refine the search to humans.
There are many studies out there comparing low carb to low fat for diabetes. The problems with these studies are the fact that the low fat group is not put on a truly low fat diet, they still eat animal protein, and the end result they look at is blood sugar NOT insulin resistance. If you do not eat any sugar then blood sugar may be artificially low, but a high protein diet devoid of carbs may be causing inflammation and insulin resistance, and this may not be picked up simply by measuring blood sugar alone. Unfortunately there are currently no randomized control trials comparing a plant based diet vs a high protein diet directly with regards to diabetes.
However, the Imperial College School of Medicine in London did the kind of comprehensive testing that truly measures whether insulin resistance is present in plant eaters vs general omnivores {
http://www.ncbi.nlm.nih.gov/pubmed/15523486}. They found 21 vegetarians and 21 omnivores and matched them for age, weight, waist circumference, and activity levels. They followed them for 7 days and made sure they ate the same amount of calories and their daily usual exercise activities were the same. Basically, the only difference between these groups was that one group avoided animal protein. They then did comprehensive testing looking at the amount of insulin produced and they actually did muscle biopsies to look at the amount of fat in the muscle. How they talked people into getting muscle biopsies I do not know. The results showed that despite eating (or maybe because of eating) a far higher carbohydrate load, the vegan group had lower insulin and had less fat in their muscle cells, which I hope you would now expect.
This study was not however a controlled intervention. It is one thing to compare vegans to omnivores but to actually make a group of people eat either a vegan diet or another type diet is much more difficult. People tend to be set in their ways, and having them stick to a diet plan is not always successful. But, if we are going to prove actual causation, we must show that taking people on a usual diet and making them remove the animal protein causes their insulin resistance to disappear.
Dr. Neal Barnard did just such a study. He and his colleagues, took 100 diabetic, overweight people, and randomized them from their usual diet to either a vegan diet or a reduced calorie, low fat ADA diet. The ADA diet was purposefully calorie reduced, and was a very moderate diet. It was low in fat and moderate in protein and carbs, leaning to low glycemic carbs. The vegan diet was not limited to calorie intake at all. The subjects could eat as much as they wanted of fruits, veggies and legumes. Oils and nuts were limited. Both group were intensively counseled over a 74 week period. They measured A1C, which is a long term measure of how well blood sugar is controlled. They also looked at weight and LDL cholesterol. My only complaint is that they did not look directly at insulin resistance, but it is difficult to do, and I think Americans are a little less interested in agreeing to muscle biopsies. The results showed that the vegans ended up eating much more carbs, yet they had significantly better blood sugar control compared to the ADA diet. The vegans also had much lower cholesterol. Despite the fact that the vegan group could eat as much as they want, they actually ended up losing slightly more weight too {
http://www.ncbi.nlm.nih.gov/pubmed/16873779} {
http://www.ncbi.nlm.nih.gov/pubmed/19339401}. It appears that a vegan diet is superior to just a low fat diet in controlling diabetes {
http://www.ncbi.nlm.nih.gov/pubmed/10446033}.
Of course, this study is worthy of the criticism I place on all the low carb studies, which is that they were simply measuring sugar levels. The difference of course is that the subjects were consuming sugars in the forms of carbs and yet they still kept blood sugar levels down. A typical days meal included oatmeals, cantaloupes, pasta, and various other fruits. Thus, the sugar is not falsely lowered and obviously their insulin sensitivity must be improving.
For the naysayers I offer another interesting prospective study {
http://www.ncbi.nlm.nih.gov/pubmed/20815907}. In this study there is no actual control group, rather they use the subjects as their own control, comparing how they do on a vegan diet compared to how they did on their standard diet. In this study they took 43 people and put them on The Daniel Fast, which is essentially a vegan diet, not really a fast. The diet gets its name from the Book of Daniel 10:2-3. Daniel was held in captivity in Babylon but was a valued asset. He was offered the King’s wine and meat, but he refused. He ate only vegetables and pulses and drank only water. The head of security was worried about the fact that Daniel would wither but Daniel suggested that they conduct a little scientific experiment (paraphrasing). He asked that the guards also follow his diet, and after 10 days he and the guards had far superior health and vigor than those who ate the rich food of the king.
The modern day Daniel diet is rich in fruits, vegetables, beans, seeds, and nuts. All junk food and all animal meats are avoided. The 43 people in this study followed the diet with excellent compliance, showing that it really is easy to do. Despite being able to eat as much as they want, they actually ended up eating less calories. They also ate less protein and a higher percentage of calories from carbs. They ate more fat than in Barnard’s study above, but the saturated fat consumption, found mainly in meat, was obviously low. It does turn out that it is specifically saturated fat that creates the inflammation, not the polyunsaturated and monounsaturated fat found in many vegetables, legumes, nuts, and fruits {
http://www.ncbi.nlm.nih.gov/pubmed/24550191}.
The subjects on this Daniel’s Fast were extensively studied. During their vegan diet they had a substantial drop in their blood lipid values and blood sugar and had trends to lower levels of inflammation and insulin. I find this especially interesting because these were not diabetics. These were basically well people (few exceptions), yet they still showed improvements in their insulin resistance. Like the biblical Daniel, they became healthier during the “fast”.
Type II Diabetes is a serious disease that has reached epic numbers and is growing. The cause of this disease is complex but the evidence is fairly clear that the typical high meat diet may to blame, and our avoidance of carbs only makes it worse. If we avoided animal protein and instead increased consumption of fruits and veggies we could substantially prevent and treat most of the type II Diabetes we encounter. This may be in part be due to the high fiber in the plants, or the phytonutrients in the plants, but it is also due to the reduction in inflammation by avoiding animal protein {Jenkins, 2003 #150} {Chandalia, 2000 #217} {Watzl, 2008 #351}."
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