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Today, we are going to explore the very important relationship between saturated fat intake and the onset of diabetes.

As we have mentioned before,“Once we control for weight, alcohol, smoking, exercise and family history, the incidence of diabetes is significantly associated with the proportion of saturated fat in our blood.”

Today we will take a deep dive to fully understand why there is such a strong link between diabetes and saturated fat consumption. We will also discuss how a plant-based diet may protect you from (or even reverse!) the disease.

What Is Insulin Resistance?

Insulin resistance is a hallmark of both prediabetes and type 2 diabetes.

So what is insulin resistance exactly (and why is it important)?

Let me explain.

Insulin is what permits glucose (sugar) in the blood to enter our (muscle) cells.

In essence, insulin ‘unlocks’ the door, allowing the glucose to come in. If there is no insulin at all (the case of type 1 diabetes), the blood sugar ‘hangs out’ in the bloodstream because it cannot get inside. That causes the blood sugar levels to rise.

But what happens if the insulin is there but is simply not working properly? In that case, the lock to the cell door is ‘blocked.’ This is what is called insulin resistance.

So what causes insulin resistance in the first place?

Insulin resistance is caused by fat.

Fat build-up inside (muscle) cells creates toxic fatty breakdown products and free radicals that ‘block’ the insulin-signaling process, close the ‘glucose gate,’ and make blood sugar levels rise.

And this cycle can happen really fast.

In fact, insulin resistance can occur in 180 short minutes (just 3 hours!) after the consumption of fat.

But there is more.

The process of insulin resistance, caused by the buildup of fat in our muscles, liver, and pancreas, can quickly worsen due to what is called the ‘twin vicious cycles.’

In the early stages of insulin resistance, the pancreas pumps out more and more insulin trying to overcome the (fat-induced) insulin resistance in the muscles. These higher insulin levels then lead to an accumulation of fat in the liver (fatty liver disease), which in turn also becomes resistant to insulin.

A ‘normal’ liver constantly produces blood sugar; it is our body’s way of keeping our brain alive between meals. After we eat a meal, the insulin released normally turns off the liver glucose production.

However, if our fatty liver becomes insulin resistant, it does not respond to these ‘normal’ signals and instead continues to pump out blood sugar on top of what we eat and floods our system with higher and higher levels of glucose.

In response, the pancreas pumps out more and more insulin to deal with high sugar levels, which furthers the accumulation of fat in the liver.

The first vicious cycle has begun; fatty muscle cells lead to a fatty liver, which just gets fattier as the entire system enters a downward spiral.

But once again, it does not end there.

Because in an attempt to ‘fix’ the imbalance, the fatty liver then tries to dump the excess fat back into the bloodstream, and that fat then builds up inside the pancreas cells—those very cells responsible for producing insulin.

Fatty muscles, therefore, lead to a fatty liver which then results in a fatty pancreas.

As this fat build-up starts to kill of pancreatic beta cells, insulin production inevitably stutters…and stops.  (Remember that the only thing that prevents us from having diabetes in the first place is the pancreas working overtime to pump out extra insulin to overcome the insulin resistance!)

In the end, we are left with the worse of two worlds.

Insulin resistance on the one side.

A failing pancreas (and insulin production) on the other.

Unable to defeat the insulin resistance or to produce higher amounts of insulin, our body’s blood sugar levels go (and remain) up.

And we have type 2 diabetes.

All Fats Are Not Created Equal

Type 2 diabetes is a condition caused by excess fat in our organs or fat toxicity.

But very importantly, it is not just ‘any’ fat—but rather saturated fats (which are mostly found in animal-based diets) that cause diabetes.

In fact, while saturated fatty acids like palmitic acid (from meat, dairy, and eggs) cause insulin resistance, plant-based monounsaturated fatty acids like oleic acid (from nuts, olives, and avocados) might even do the opposite—i.e. they may improve insulin sensitivity.

Furthermore, saturated fats not only induce insulin resistance (as explained above) but they may also cause the death of pancreatic beta cells, impeding insulin secretion altogether.

This means that saturated fats have a very powerful, negative effect on insulin action both in the short- and the long-term.

Why Plant-Based Diets Are So Important

The idea that a plant-based lifestyle can benefit those with type 2 diabetes dates all the way back to the 1930s when it was shown that a diet based on vegetables, fruits, grains and beans was one of the most effective nutrient-based treatments for diabetes.

The Adventist-2 study, which included 89,000 people and extended across 50 years, clearly shows that those who eat meat one or more days a week have significantly higher rates of diabetes.

And the more often meat is eaten, the more frequent the disease. In contrast, those who eat strictly plant-based (even at the same weight) are 78 percent less likely to suffer from diabetes.

In the same vein, researchers at the Imperial College of London looked at the insulin resistance and muscle fat of vegans versus omnivores.

When they compared plant-eaters with omnivores of the same body weight, they discovered that the plant-eating subjects enjoyed better insulin sensitivity, blood sugar, and insulin levels as well as significantly better pancreatic beta-cell functioning.

In another study, participants were asked to eat a high-carbohydrate, high-fiber diet in quantities high enough that they did not lose weight.  That was to assess the benefits of a plant-based diet vis-à-vis diabetes reversal independent of weight loss.

The results were startling; overall insulin requirements were cut by 60 percent, and 50 percent of the subjects (some of whom had been taking insulin for decades) were able to get off insulin altogether.

And these remarkable changes did not happen over months—but 16 short days!

This research showed that type 2 diabetes can be reversed simply by adopting a whole food, plant-based diet even when no weight loss occurs.

But are these dramatic differences explained by the elimination of animal foods/saturated fats? Or is there something ‘inherent’ in plants that helps reduce the risk of diabetes so dramatically?

The answer is a bit of both.

Obviously, the reduction of saturated fats—the main culprit when it comes to insulin resistance—goes a long way to decreasing your risk for diabetes. But a plant-based diet alone also has a lot going for it when it comes to battling diabetes including antioxidants, phytonutrients, and fiber.

What About Eating Just a “Little Bit” of Meat?

I am often asked if it is okay to eat a ‘little bit’ of meat?

The short answer to this is “No.”

A recent study examined this question, comparing Buddhist vegetarians to Buddhist non-vegetarians eating a traditional Asian diet. This meant that the women ate a single serving of meat a week while the men ate a serving every few days—approximately 8 percent of the average US meat intake for men, 3 percent for women.

The results? The men who ate vegetarian only versus those who ate the traditional Asian diet exhibited 50 percent less diabetes while the women exhibited 75 percent less! This study shows that even small quantities of meat can still make a BIG negative difference.

Another prospective study examined ~17,000 people who had been followed for 12 years. They found an 8 percent increase in the risk of diabetes for every 50 grams of daily meat consumption (note that one chicken breast, bone and skin removed, is 172 grams!).

If you want to decrease your risk of getting diabetes, you need to drastically reduce your saturated fat intake. And since saturated fats are mainly found in animal-based foods, those should not have a place on your table.

In summary, high-calorie diets rich in saturated fats cause type 2 diabetes.  Based on the scientific evidence, you may greatly improve your chances of avoiding (or even reversing) the disease by transitioning to a low-fat, whole food, plant-based diet.

Rosane Oliveira, DVM, PhD

President & CEO, Plant-Based Life Foundation | Dr. Rosane Oliveira combines a lifelong passion for nutrition with 25 years of genetics research to create programs that help people develop healthy habits on their journey towards a more plant-based lifestyle. She is a Visiting Clinical Professor in Public Health Sciences and was the founding director of the first Integrative Medicine program at the UC Davis School of Medicine. She completed her postgraduate studies in Brazil and did her postdoctoral training in immunogenetics and functional genomics at the University of Illinois at Urbana-Champaign.