Type 2 Diabetes: Causes, Progression, Dangers, and the Possibility of Remission

What is Type 2 Diabetes?

The number of people living with diabetes worldwide has quadrupled over the past 40 years.

In 2019 alone, the World Health Organization estimated that 1.5 million deaths were directly caused by this disease, which is also responsible for blindness, kidney failure, heart attacks, strokes, and lower limb amputations.

I will admit something personal: I have always been genuinely frightened of diabetes, and I cannot fully explain why. I have no family history of the disease, and this fear, bordering on a phobia, took root well before I ever came across these alarming statistics. I think what really shaped it was witnessing, firsthand, during my early years working in a pharmacy, the day-to-day impact this disease has on people’s lives.

• I saw the distress caused by seemingly minor but genuinely disruptive problems, like the loss of sensation in the fingertips.
• I learned that diabetes is a recognized risk factor for certain forms of dementia.
• I thought about what it must feel like to lose the freedom to choose what, how, and how much to eat.
• I imagined the burden of living with constant pain from neuropathy.
• And I directly witnessed patients who, for years on end, needed daily dressing changes for open wounds that simply refused to heal.

In terms of overall mortality, high blood pressure is probably an even greater risk on its own, but as the saying goes, it is a silent killer, with no symptoms to warn you.

Type 2 diabetes is much the same in its early stages, but once it truly takes hold, it can be devastating. Here, however, is the good news:

• Type 2 diabetes can almost always be prevented.
• It can often be effectively treated.
• And in some cases, it can even be reversed, a statement that, until just a few years ago, would have sounded like medical heresy.

Yes, some patients with diabetes can achieve remission (to learn more, see: Can You Reverse Diabetes?).

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What Is Type 2 Diabetes?

Let’s start with a clear definition, to better understand what we’re discussing: diabetes is a chronic metabolic disease.

• Metabolic, because it is closely tied to how the body processes the sugar we consume as an energy source.
• Chronic, because in most cases it is not only a long-term condition, but very often an incurable one.

There are several forms of diabetes, but the two main types are type 1 and type 2 diabetes. Both share a common thread: the body’s difficulty in managing circulating blood sugarses, could not be more different.

• When we eat something, let’s say a plate of french fries, the sugar it contains rapidly enters the bloodstream, causing blood glucose levels to spike upward.
• The blood now contains much more sugar, which continues to rise as the fries are progressively digested and absorbed.
• In response, the body produces insulinsugar out of the bloodstream, lowering blood glucose and preventing the damage that would otherwise result.

A person with type 1 diabetes is unable to produce insulin at all, and must therefore administer it externally through injections.

A person with type 2 diabetes, on the other hand, is very much capable of producing insulin, at least until the final stages of the disease. However, production has been so frequent, and at such high levels, for so long, that muscle cells are no longer able to respond properly. The key simply no longer fits the lock the way it should.

It’s a bit like taking an athlete and subjecting them to daily, intense training for years, even decades, without ever allowing rest or recovery periods. Sooner or later, an irreversible collapse in performance would be inevitable. We would have, in a sense, burned them out.

In this article, we will focus on type 2 diabetes, which accounts for roughly 9 out of every 10 cases of diabetes. You have probably already guessed the main causes, which are, unsurprisingly, closely tied to lifestyle, although some aspects remain genuinely controversial and not entirely understood, even in the most recent scientific literature.

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Why Does It Develop?

It would not be far from the truth to say that every person with type 2 diabetes has their own unique combination of contributing factors. Historically, type 2 diabetes was more commonly diagnosed in adulthood, often after age 40, but the age at diagnosis has been decreasing in many populations. Rising rates of obesity, sedentary lifestyles, and other metabolic risk factors have contributed to the increasing occurrence of type 2 diabetes among younger adults and, in some cases, adolescents.

Obesity is one of the most significant risk factors for type 2 diabetes. Many people with diabetes are overweight or obese, although diabetes can also occur in people with a normal body weight. Obesity substantially increases the risk of developing type 2 diabetes, with some studies estimating that people with obesity may have a risk several times higher than those with a healthy body weight.

Among other modifiable risk factors, we should of course mention diet, particularly when it is excessively rich in simple sugars and saturated fats (found predominantly in animal-derived foods), along with a sedentary lifestyle and smoking.

Several medical conditions also represent risk factors for developing diabetes, including high blood pressure, hyperlipidemia (elevated cholesterol and triglyceride levels), gout, and a prior history of gestational diabetes during pregnancy. If you look closely, though, all of these conditions are, in one way or another, connected to lifestyle factors.

Then there are the non-modifiable factors, such as age, an excessively high or low birth weight, and family history.

Family history, meaning some degree of genetic predisposition, is often misunderstood, leading to convenient or overly catastrophic interpretations. I hear these two statements far too often:

1. “No one in my family has diabetes, so I’m not at risk either”.
2. “A close relative of mine has diabetes, so I’m definitely going to get it too”.

And both statements usually end with something like: “So there’s no point making any sacrifices, it wouldn’t change anything anyway”.

That’s simply not true.

Genetics is only one of many factors involved. It certainly carries meaningful weight, but as my old math teacher used to say, it is neither a necessary nor a sufficient condition. And there is a world of difference between diabetes with blood sugar levels just barely above normal and diabetes with the same diagnosis but far more severe glucose levels; the course of the disease itself remains, to a large extent, in our own hands.

According to the American Diabetes Association, when identical twins, who share exactly the same genetic makeup, are considered, if one twin develops type 2 diabetes, the other twin’s risk is approximately 75 percent. That is certainly a high risk, but it is not an inescapable sentence, especially considering that, as mentioned earlier, every patient’s situation is unique, and active prevention through lifestyle changes can dramatically alter the course of the disease. It’s also worth noting that it is genuinely difficult to cleanly separate the influence of DNA from shared family habits around diet and physical activity, so the true genetic contribution may actually be smaller than it appears.

But that example involved identical twins. If instead we consider a diabetic parent, the risk to the child is considerably lower, somewhere in the range of 10 to 15 percent.

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The Progression of Type 2 Diabetes

To understand how the diagnosis is actually made, beyond the cold numbers from a blood test, I think it’s helpful to offer a quick overview of how the disease typically evolves. I want to be upfront that I will simplify certain concepts here for the sake of clarity. I’ll walk you through the various possible stages, but it’s important to keep in mind that this path can vary considerably from one patient to another; it is not set in stone.

Blood glucose, the amount of sugar circulating in the blood, needs to be kept within a fairly narrow range of normal values:

1. It needs to stay above roughly 60 to 70 mg/dL so that there is enough available energy for organs like the brain and eyes.
2. But at the same time, it should exceed 100 mg/dL as rarely and as briefly as possible, in order to avoid dangerous long-term complications.

The effect of insulin, the hormone the body uses to keep blood sugar from rising too much after a meal, can be summarized as follows:

• The food we eat reaches the intestine.
• The sugar it contains gets absorbed into the bloodstream.
• Blood glucose levels rise.
• The pancreas detects this rise and produces insulin.
• Insulin flips a switch on muscle cells, prompting them to start pulling sugar out of the blood.
• Blood glucose levels come back down.
• Insulin production also decreases, until things return to their starting baseline.

Unfortunately, when insulin is produced in excess, it also has several secondary effects, including increases in:

• Body weight
• Blood pressure
• Cholesterol levels

It’s therefore easy to understand just how important it is to avoid unnecessary excess insulin production, primarily through diet.

Now let’s think about a typical fast-food meal, which represents one of the worst possible combinations when it comes to cardiometabolic prevention: as delicious as it is destructive.

Let’s start our meal with a nice burger and a side of french fries. We’re taking in rapidly absorbed starches, both from the bun made with refined flour and from the fries, along with heavily processed meat loaded with saturated fat and salt (let’s not even get into the potential carcinogens formed from grilling meat and deep frying). All of this is washed down with the simple sugars of an extra-large soda, and perhaps topped off with a dessert, yet another concentrated dose of saturated fat and sugar.

The net result is that blood sugar spikes sharply, because there is a large amount of sugar, and it is absorbed extremely quickly. The higher the blood sugar spike, the more insulin the pancreas has to produce. But the situation is made even worse by the saturated fats present in the meal, which act like chewing gum stuck in the locks where insulin is supposed to bind, preventing it from doing its job properly. As a result, the process takes longer, and even more insulin needs to be produced to compensate.

If we allow ourselves a meal like this occasionally, within the context of an otherwise healthy lifestyle, that’s perfectly fine. We’re human, and we need this kind of occasional indulgence too, which also carries important social and psychological value (although, honestly, it wouldn’t take much to make it a considerably healthier meal: water instead of soda, whole grain bread, fries with the skin left on, higher-quality meat, and a side salad).

But if this instead becomes, more or less, a daily habit, think about:

• Consistently refined pasta and grains
• Excessive salt intake
• Industrially processed ready-made meals loaded with sugar and fat
• Meat consumed every single day (itself independently linked to increased diabetes risk)

Over the years, the body is subjected to a metabolic workload that, eventually, it may simply no longer be able to sustain. It was once believed that carbohydrates were the main culprit, and certainly, when consumed as refined sugars or starches, they do represent a considerable metabolic burden. More recently, however, attention has shifted toward dietary fat, which, as we’ve seen, actively interferes with insulin’s ability to do its job. This includes saturated fat consumed directly through diet, as part of the meal itself, but also fat already stored within the body and circulating in the bloodstream, which is very common in cases of overweight and obesity.

Insulin Resistance and Hyperinsulinemia

The growing difficulty insulin faces in exerting its effect is the first step on the path toward developing diabetes, and it is known as insulin resistance: cells gradually become less responsive to the hormone’s action.

However, blood sugar cannot be allowed to remain elevated, so the pancreas has only one option available: produce even more insulin to compensate for the reduced sensitivity of the cells.

This marks the second step on the path toward diabetes: hyperinsulinemia (excessively high insulin levels).

At this stage, we don’t notice any symptoms, we don’t perceive any difference, and blood glucose levels, both fasting and after meals, remain essentially normal. However, if we were to measure the amount of insulin produced after a meal, we would already be able to detect the first warning signs of trouble.

But, as mentioned, we don’t notice anything, so we feel no particular need to change our diet, and the amount of insulin required keeps climbing higher and higher, until eventually insulin resistance becomes so severe that the pancreas, despite its best efforts, is no longer able to produce enough insulin to effectively control blood sugar, which then gradually begins to rise.

Prediabetes

This can essentially happen in two ways:

• Impaired fasting glucose, meaning a fasting blood sugar level that now exceeds normal values, falling between 100 and 125 mg/dL.

• Impaired glucose tolerance, meaning blood sugar levels after a meal that exceed normal values, falling between 140 and 199 mg/dL.

Naturally, one condition does not exclude the other, and together they fall under what used to be called prediabetes, a condition that is not yet, strictly speaking, a disease, but that nonetheless represents a significantly elevated risk of developing full-blown type 2 diabetes. Statistics vary somewhat from one source to another, but roughly speaking, about 1 in 5 people in this condition will go on to develop diabetes within 5 years.

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Diagnosing Type 2 Diabetes

We are now in a better position to define the diagnostic criteria for type 2 diabetes, which requires meeting one or more of the following conditions:

• A fasting blood glucose level of 126 mg/dL or higher, measured on at least two separate occasions.

• A blood glucose level above 200 mg/dL at any time of day, provided the classic symptoms of diabetes are also present.

• A blood glucose level of 200 mg/dL or higher two hours after an oral glucose tolerance test (confirmed on two separate occasions).

• A glycated hemoglobin (HbA1c) level of 6.5% or higher (confirmed on two separate occasions).

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What to Do Immediately If You Have High Blood Sugar

Here’s the problem: there is genuinely nothing you can safely do on your own if you discover a very high or extremely high blood glucose reading. The only real options are oral medications, or insulin in cases where levels are high enough to create a risk of seizures or diabetic coma.

So, if you’ve discovered a very high blood sugar reading, whether or not you already know you have diabetes, contact your doctor immediately, or go to the emergency room if you experience serious symptoms such as rapid breathing, a sense of confusion, or difficulty staying awake (lethargy).

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What to Do After a Type 2 Diabetes Diagnosis

Every patient’s situation is unique, and not every stage described above necessarily occurs in every case; the progression can be faster or slower, and some patients develop greater insulin resistance than others. What I really want you to understand, though, is the general pattern of possible progression, because there are two important concepts to grasp here:

1. Each successive stage increases the risk of developing full diabetes.
2. The good news is that, regardless of where you currently stand, it is theoretically possible to reverse course, in some cases even after an official diabetes diagnosis. However, this fundamentally requires making changes to your lifestyle, including:

• Working toward your ideal body weight, or, as we always say, at the very least losing a portion of any excess weight
• Engaging in regular physical activity
• Quitting smoking
• Limiting alcohol consumption
• And, of course, following an appropriate diet

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Diet for the Diabetic Patient

When talking about diabetes, it’s natural to immediately think of a low-carbohydrate diet, right? And indeed, several studies have investigated this approach, though with mixed results. A far more promising strategy appears to involve carefully selecting, rationalizing, and in some cases limiting dietary fat, combined with essentially unrestricted consumption of whole grains, and more broadly, a diet centered almost exclusively on whole plant foods.

The results of this approach have been remarkable and well documented in the scientific literature. As a starting point, I would recommend the body of work by Dr. Neil Barnard, who has written several patient-oriented books, including one specifically dedicated to diabetes, as well as the extensive educational work of Dr. Michael Greger, who documents, with impressive rigor, the scientific literature underlying his recommendations.

That said, these are dietary approaches that genuinely require guidance from qualified healthcare professionals, because a strictly, or even loosely, vegan diet is not simply a diet with meat removed; it requires additional care and planning to avoid nutritional deficiencies.

But most importantly:

• Initially, medications should not be changed or discontinued; they should be continued exactly as prescribed.
• Because some diabetes medications can cause dangerous episodes of hypoglycemia (excessively low blood sugar) if blood sugar control improves significantly, a doctor needs to closely monitor progress in order to decide when, and by how much, medication doses should eventually be reduced.

Since the same lifestyle changes, diet and physical activity, can also improve blood pressure, cholesterol, and triglycerides, any medications targeting these conditions may also eventually need to be adjusted, but again, always and only after improvement has already been documented, never in anticipation of it.

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Symptoms of Diabetes

Earlier, we briefly mentioned the possible symptoms of diabetes, so it’s worth taking a closer look at what these might actually be. In the vast majority of cases, unfortunately, there are none at all. It is not uncommon for a patient to remain completely unaware of full-blown diabetes until the disease has already progressed quite far. We mentioned earlier that a blood glucose reading above 200 mg/dL at any time of day qualifies as diabetes, but the first noticeable symptoms may not appear until levels reach 250, or even 300 mg/dL.

The classic triad of symptoms typical of diabetes includes:

• Hunger, because the body desperately needs sugar for energy, and despite having plenty circulating in the bloodstream, it is unable to actually access and use it.

• Increased urine output, because the kidneys are desperately trying to flush out as much excess sugar as possible, in an attempt to limit the damage.

• Excessive thirst, because the fluid lost through frequent urination puts the body into a state of constant, low-grade dehydration.

And additionally:

• Blurred vision
• Fatigue
• Unexplained weight loss
• Agitation
• Even minor wounds that fail to heal
• Unexplained infections that are difficult to treat, for example recurrent genital yeast infections or oral thrush
• Dry mouth
• Dry skin
• And erectile dysfunction

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Complications of Type 2 Diabetes

Here’s the problem: these symptoms may sound clear and unmistakable, but imagine only a few of them appearing, perhaps in a very mild, intermittent form at first. It isn’t always obvious that a doctor’s visit is urgently needed, and meanwhile, elevated blood sugar continues to cause damage, sometimes for months, sometimes for years, before the disease is finally diagnosed. This damage is often irreversible and can affect:

• Vision, potentially progressing to complete blindness
• The kidneys, potentially progressing to the need for lifelong dialysis
• The nerves, causing pain, loss of sensation, and constant tingling
• The immune system, resulting in ulcers that simply won’t heal, sometimes ultimately requiring amputation of the foot or leg
• The arteries and heart, with a significantly increased risk of heart attacks and strokes

Something that struck me deeply was reading how rarely a diabetic patient actually ends up on dialysis, simply because, in most cases, a fatal cardiovascular event occurs first.

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When to See a Doctor

Given how often type 2 diabetes develops silently, without obvious symptoms, it is important to seek medical evaluation proactively rather than waiting for warning signs to appear. You should see a doctor for blood sugar testing if you have:

• A family history of type 2 diabetes, particularly in a parent or sibling
• Overweight or obesity, especially with excess abdominal fat
• A sedentary lifestyle combined with a diet high in refined carbohydrates and saturated fat
• High blood pressure, high cholesterol, or high triglycerides
• A personal history of gestational diabetes or having given birth to a baby weighing more than 4 kg (9 pounds)
• Polycystic ovary syndrome (PCOS), which is associated with increased insulin resistance
• Any of the classic symptoms described above, including excessive thirst, frequent urination, unexplained fatigue, or unexplained weight loss

If you already have a diagnosis of diabetes or prediabetes, regular follow-up with your doctor is essential to monitor blood sugar control, screen for early complications affecting the eyes, kidneys, nerves, and cardiovascular system, and adjust treatment as needed based on your progress with lifestyle changes.

Seek immediate emergency care if you or someone you know with diabetes experiences confusion, extreme drowsiness, rapid breathing, fruity-smelling breath, or loss of consciousness, as these can be signs of a life-threatening diabetic emergency.

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Frequently Asked Questions

Can type 2 diabetes really be reversed?

In some cases, yes, particularly when caught early, in the prediabetes stage or shortly after diagnosis, through significant, sustained weight loss, dietary changes, and increased physical activity. Remission does not mean the underlying predisposition disappears entirely, but many patients can achieve normal blood sugar levels without medication for extended periods, sometimes indefinitely, with continued healthy habits.

Is type 2 diabetes only caused by eating too much sugar?

No, this is an oversimplification. While excessive intake of refined sugars and simple carbohydrates plays a role, dietary fat, particularly saturated fat, total caloric excess, physical inactivity, genetics, and other metabolic factors all contribute significantly to the development of insulin resistance and type 2 diabetes.

Can a thin person develop type 2 diabetes?

Yes, although it is less common. While the majority of people with type 2 diabetes are overweight or obese, a meaningful proportion of patients have a normal body weight, particularly if they carry excess fat internally around the organs (visceral fat) despite an otherwise normal appearance, or if they have a strong genetic predisposition.

How often should blood sugar be checked if I have prediabetes?

This should be determined individually with your doctor, but generally, patients with prediabetes are advised to have blood glucose or HbA1c levels rechecked at least once a year, along with more frequent monitoring if lifestyle changes are being actively implemented to track progress.

Does type 2 diabetes always eventually require insulin?

Not necessarily. Many patients with type 2 diabetes can maintain good blood sugar control for years, or even indefinitely, using oral medications combined with lifestyle changes. Insulin typically becomes necessary only when the pancreas’s own insulin production has declined significantly, which tends to happen after many years of poorly controlled disease, though this varies considerably between individuals.

Can children develop type 2 diabetes?

Yes, unfortunately, rates of type 2 diabetes in children and adolescents have been rising steadily worldwide, closely paralleling increasing rates of childhood obesity and sedentary lifestyles. This represents a significant and growing public health concern, as earlier onset generally means a longer lifetime exposure to the risk of complications.

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Conclusion

Diabetes can almost always be prevented, can often be effectively treated, and can sometimes even be reversed, but it takes willpower, and it takes a certain degree of sacrifice, because it is never easy to give up that delicious burger most of the time, and it takes real effort to go out walking, or better yet running, when it’s dark outside and the temperature is barely above freezing. But it is worth it, because the goal isn’t simply to grow old at any cost, but to grow old in good health.

I remember, with great affection, a patient I served for years at the pharmacy, before diabetes eventually took her from us. Every single time, she would tell me about how she took 19 different medications every day, between pills and insulin. This was some years ago, before combination medications containing multiple active ingredients became widely available, so she was taking 4 to 5 tablets just for treatment-resistant high blood pressure, a couple more for cholesterol and triglycerides, several for diabetes itself, antibiotics for open ulcers she had been living with for years, antidepressants, and probably a few other things besides.

These medications gave her years of life that would have been unimaginable just 30 or 40 years earlier, but at what cost? Certainly, the chance to watch her grandchildren grow up was priceless. But today, we know that making a few sacrifices now allows us to reap far greater rewards in the years that follow, not unlike investing money: putting in even a small amount, but doing so consistently, every single day, and starting as early as possible, increases the likelihood of a much richer return, proportional to the effort we put in along the way.

I use the word “probability” deliberately, because unfortunately, yes, it is a probability, not a guarantee. But I remain firmly convinced that the cost is always worth the benefit. It is never too early, and never too late, to start investing in your future, especially, and above all, when it comes to your health.

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Sources and Bibliography

• World Health Organization (WHO). Diabetes: Key Facts. https://www.who.int/news-room/fact-sheets/detail/diabetes
• American Diabetes Association (ADA). Genetics of Diabetes. https://diabetes.org/about-diabetes/genetics-diabetes
• Diabetes.co.uk. Diabetes and Genetics. https://www.diabetes.co.uk/diabetes-and-genetics.html
• Hallberg SJ, et al. Reversing Type 2 Diabetes: A Narrative Review of the Evidence. Nutrients. 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520897/
• Barnard ND, et al. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care. 2006. https://pubmed.ncbi.nlm.nih.gov/16760995/
• American Diabetes Association (ADA). Standards of Medical Care in Diabetes. Diabetes Care. 2023.
• International Diabetes Federation (IDF). IDF Diabetes Atlas. 10th Edition, 2021.
• Centers for Disease Control and Prevention (CDC). Type 2 Diabetes. cdc.gov.
• Tabák AG, et al. Prediabetes: a high-risk state for diabetes development. Lancet. 2012;379(9833):2279-2290.