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What is Prediabetes?
Prediabetes is not just a sign of future problems. It’s an indication that your body has current metabolic dysfunction. Your doctor will typically diagnose it through blood tests that reveal glucose levels higher than what’s considered optimal but not yet high enough to be considered Type 2 diabetes. It’s usually a sign of elevated insulin and insulin resistance, which can lead to several chronic diseases.
Hearing that you have prediabetes may come as a surprise—although more than one in three American adults may have it, 84% of those have no idea. And it is not a condition that you should ignore: Even prediabetic blood sugar levels can cause adverse health outcomes, including cognitive decline, an increased risk of heart disease, and damage to blood vessels in the eyes that leads to diabetic retinopathy.
Fortunately, most people can reverse prediabetes by making diet and lifestyle changes that improve blood sugar control and reduce insulin resistance.
How Do You Get Prediabetes?
Prediabetes is ultimately a state of insulin resistance. Insulin is the hormone that helps cells absorb glucose. When we have consistently elevated glucose levels, the body has to pump out high levels of insulin to deal with it. Over time, high insulin levels can make cells numb to its effects, requiring more insulin to balance blood sugar, leading to a vicious cycle. That’s called insulin resistance, and over time it can lead to chronic conditions, such as heart disease, diabetes, infertility, Alzheimer’s disease, and more.
That’s the simple version, but insulin resistance is a complex process spurred on and exacerbated by several factors throughout the body. For example, chronic overnutrition—overeating—leads to fat accumulation in tissue such as muscle and the liver. These fat deposits stress the cells, leading to inflammation and promoting changes that can spur insulin resistance in those tissues. Overnutrition also stresses the fat cells and can cause inflammation, cell death, and insulin resistance in these cells. This can lead to fat being broken down and released into circulation, where it can take up residence in the liver and muscle and worsen insulin resistance in those tissues.
The process of developing insulin resistance can start as many as 13 years before your elevated glucose levels appear on diagnostic tests. That’s because the body can compensate for rising glucose for years by simply secreting more and more insulin to overcome worsening insulin resistance. Unfortunately, this trend eventually ends in skyrocketing glucose, triggered by two things: insulin resistance becomes so severe that your body can’t produce enough insulin to handle the high glucose levels, and insulin-producing pancreatic cells lose function.
And insulin resistance isn’t the only potential danger of chronically high glucose levels. Excess blood sugar can also lead to other cell-damaging effects, including inflammation, oxidative stress, and advanced glycation end products, which can themselves cause inflammation and lead to problems from wrinkles to Alzheimer’s disease.
Other factors that can contribute to developing prediabetes include:
- Stress, both acute and chronic: Stress triggers the release of cortisol, which stimulates the production of more glucose and reduced insulin sensitivity
- Sleep deprivation: Even a few nights of poor sleep can lead to increased stress hormones and growth hormone, which decreases glucose uptake and insulin sensitivity
- Lack of exercise: Physical activity can increase muscle insulin sensitivity, and your muscles can absorb glucose without a rise in insulin
- Family history: Having at least one first-degree relative with Type 2 diabetes can increase your risk of prediabetes by 26%.
- Gestational diabetes (GD): One review found that women who had GD were 10 times more likely to develop Type 2 diabetes later in life, suggesting that GD can lead to lasting blood sugar impairment.
How Do We Diagnose Prediabetes?
Prediabetes is typically diagnosed by looking at overall glucose levels, either through a fasting glucose test, which looks at the glucose concentration level in your blood uninfluenced by a recent meal, with an HbA1c test. That roughly captures your average glucose levels over the past three months (about how long a red blood cell, or hemoglobin [Hb], survives). For fasting glucose, the benchmarks are typically:
- Normal: Under 100 mg/dL
- Prediabetes: 100–125 mg/dL
- Diabetes: Higher than 125 mg/dL
For A1c, the benchmarks are:
- Normal: 5.7% or lower
- Prediabetes: 5.8%–6.4%
- Diabetes: 6.5% or higher
Glucose tolerance is another marker for prediabetes, typically tested via an oral glucose tolerance test, which looks at how quickly your body clears a glucose load.
It’s important to note that just being in a specific category does not mean that it is at an optimal value. For example, a fasting glucose level of 99 mg/dL, while in the “Normal” range, is still less than optimal than a fasting glucose in the 70s or 80s and should still be lowered with diet and lifestyle changes. In his book, Metabolical, Dr. Robert Lustig states, “Once fasting glucose rises over 100 mg/dL, metabolic syndrome is in full force. A fasting glucose of 90 mg/dL is already questionable.”
In addition, single-point-in-time glucose measures like fasting glucose may miss some portion of people in this risk group by failing to capture glucose variability—how much your blood sugar changes in response to a meal, which can have consequences of its own.
Recent research developed three “glucotypes” (low, moderate, severe) based on glucose variability as measured by a continuous glucose monitor. The glucotypes correlate to how much time someone spends in the more variable ranges after a meal. The more variable the glucose, the higher risk they are for either being prediabetic or developing prediabetes. Some people appear to have higher, faster rises than others, which could indicate early insulin resistance.
In the study, researchers identified several people who had “normal” glucose as defined by an oral glucose tolerance test but had severe variability, which could indicate that metabolic dysfunction has already begun to set in despite their glucose levels. Other research agrees that glucose variability is important but argues that glucotypes are a less valuable model than just looking at mean glucose levels.
Can You Reverse Prediabetes?
The good news: for most people, the answer is yes. However, several factors influence the likelihood of progression from prediabetes to Type 2 diabetes, including how we define prediabetes (there is no internationally agreed-upon standard) and your current state of glucose impairment. One study found that people with an A1c of 6-6.5% have a 25-50% risk of reaching diabetic levels within five years, whereas the risk with an A1c of 5.5–6% is 9-25%.
Multiple studies suggest that lifestyle changes in people with prediabetes can lower glucose levels and prevent the development of Type 2 diabetes. An NIH study showed that people at high risk of diabetes who participated in a lifestyle change program had a 58% lower chance of developing diabetes than a placebo group.
Does a prediabetes diagnosis spur this behavior change? Research is mixed. A 2016 review found that a prediabetes diagnosis “caused a radical change in the way [people] viewed themselves and their health, which was sufficient to make appropriate lifestyle changes.” However, the same review found that many people didn’t fully understand the diagnosis or lifestyle changes they should make. Research also shows that while the diagnosis can empower some people, it can deflate others.
All of this suggests that what’s needed is more education around healthy glucose levels and metabolic behaviors. It’s possible to decrease blood sugar levels and increase insulin sensitivity to reverse prediabetes through lifestyle modifications. These include weight loss, diet changes, quitting smoking, and exercise. But people need education about those changes.
It’s also important to note that some people can feel as though they are doing everything right and still have difficulty bringing glucose levels down. One way to think about this is through a systems biology approach in which we consider the body (the system) in different states: 1) a stable, healthy state, resilient to changes (glucose spikes may not be as damaging); 2) an unstable pre-disease state in which the body is beginning to tip toward prediabetes (maybe fasting glucose remains in the normal range, but only through unsustainably high levels of insulin secretion); and 3) a stable disease state, in which the body has crossed into a diabetic or high prediabetic state, and it becomes more difficult to reverse back to a stable, healthy state. The takeaway is that the earlier you are in the process of metabolic dysfunction, the easier it may be to use modest lifestyle changes to get your blood glucose back in the desired range.
How Long Will It Take to Reverse Prediabetes?
How long it will take to bring glucose levels back to normal from a prediabetic state depends on the severity of your glucose impairment or insulin resistance, the condition of the rest of your health (including obesity), and what steps you’re taking to improve your metabolic health.
A study from the early 1990s showed that more than 50% of participants with impaired glucose tolerance who went through a lifestyle intervention program could restore normal glucose tolerance within six years. In another study, in Mexico, 22.6% of participants regressed from prediabetic to normal glycemia within an average of 2.5 years with no intervention.
The CDC suggests that losing just 5 to 7% of your body weight and exercising 150 more minutes per week can cut your risk of developing diabetes by 58%. How long that takes to accomplish is individual and based on the degree of lifestyle changes you make.
How to Reverse Prediabetes Naturally
The best way to reverse prediabetes is to aim for stable blood sugar and efficient glucose processing. Doing so requires a combination of behaviors, like choosing whole, healthy foods, managing sleep and stress, moving your body frequently, getting enough micronutrients, and supporting your microbiome.
Eat a Clean Diet
Choosing foods and meals that regulate your blood sugar levels is a cornerstone to prediabetes prevention. Although glucose responses can vary among individuals, focusing on whole foods (not processed) with no added sugar and a low glycemic index is likely to produce stable blood sugar. [More eating tips below!]
Related article: 110 Foods unlikely to spike your blood sugar
Research has shown that following a calorie-restricted low glycemic index diet focused on high-quality foods for one year, along with physical activity and psychological support, resulted in a 13-pound weight loss and reversed prediabetes in about 38% of participants who had obesity.
A company called Virta has shown that prediabetes reversal is possible with individualized nutrition and care through a remote, virtual platform. In a two-year study, Virta found that 97% of participants with prediabetes avoided progression to Type 2 diabetes, and 52% reversed prediabetes.
Exercise, along with diet, is the second cornerstone to reversing prediabetes. The CDC recommends 150 minutes of moderate exercise, such as brisk walking, per week to improve insulin sensitivity and bring down blood sugar. Frequent movement is more important than intensity activity. Low-intensity exercise is powerful enough to help improve the way the body processes glucose, making a case for taking a post-meal walk.
Lose Excess Weight
Excess weight can result in a buildup of liver and pancreatic fat, which decreases the liver’s insulin response and, consequently, raises blood sugar and weakens pancreatic beta-cell function. Weight loss, on the other hand, helps control glucose production in liver cells and also reduces stress on the pancreas so that beta cells can shake off past damage and resume healthy insulin secretion.
One study that followed participants in a diabetes prevention program for around three years found that weight loss was a significant factor in prediabetic participants getting back to optimal glucose tolerance. Another study following people in the same program found that weight loss as part of a lifestyle intervention was the most significant factor in keeping people from progressing to a diabetic state—risk went down 16% for every 1kg lost.
Get Better Sleep
Poor sleep can impair glucose processing and increase insulin resistance, even over short periods. The reason may be because sleep deprivation can increase levels of hormones associated with the sympathetic nervous system (“fight or flight response”), which plays a role in how our body makes and uses glucose. Shorting yourself on sleep also affects other hormones, including those that regulate appetite. Aim for seven to eight hours per night. There’s also evidence that sleep apnea contributes to impaired glucose control, perhaps because of the way it interrupts sleep and is more prevalent among people with Type 2 diabetes.
Related article: How does sleep affect blood sugar?
Stress prompts the release of hormones like cortisol, adrenaline, and epinephrine. This stimulates the liver to create or release glucose and makes the liver acutely insulin resistant. Evolutionarily, this may have made sense: making sure our body has enough quick fuel (glucose) to respond to a threat. But today, when most stressors are psychological, this reaction just leads to elevated blood sugar levels.
Nicotine makes insulin less effective in your body. Smokers rely on a greater secretion of insulin to maintain their blood sugar. They may also have larger waistlines, and visceral fat has a deleterious effect on metabolic function. In addition, smoking affects vascular function, which may also affect the way cells respond to insulin.
How to Reverse Prediabetes With Diet Changes
Eating to improve glucose levels and improve insulin sensitivity means not just eating for stable glucose but also trying to eat a whole-food, healthy diet that will support your body’s metabolic systems, from cellular health to a healthy liver.
Related article: 10 of the worst foods for blood sugar—according to CGM data
Through its Diabetes Prevention Program, the CDC has diet recommendations for reversing prediabetes. Other research has examined the effect of diet on reversing Type 2 diabetes and found a generally Mediterranean diet to be effective. However, studies show that minimizing post-meal glucose spikes is essential for optimal blood sugar control and that glucose responses to foods are highly individual. For example, the CDC recommendations include starchy vegetables and grains, which can cause blood sugar spikes for some people. Ultimately, a combination of principles and personal nutrition may be the optimal solution for reversing metabolic dysfunction.
In the most recent 2021 guidelines from the American Diabetes Association, they, for the first time, acknowledge this individuality in recommending diets for reversal of diabetes and offer the following guidelines:
- There is not an ideal percentage of calories from carbohydrate, protein, and fat for all people to prevent diabetes; therefore, macronutrient distribution should be based on an individualized assessment of current eating patterns, preferences, and metabolic goals.
- A variety of eating patterns … may be appropriate for patients with prediabetes, including Mediterranean-style and low-carbohydrate eating plans.
- Observational studies have also shown that vegetarian, plant-based (may include some animal products), and Dietary Approaches to Stop Hypertension (DASH) eating patterns are associated with a lower risk of developing Type 2 diabetes.
- Evidence suggests that the overall quality of food consumed, with an emphasis on whole grains, legumes, nuts, fruits, and vegetables and minimal refined and processed foods, is also associated with a lower risk of Type 2 diabetes.
- As is the case for those with diabetes, individualized medical nutrition therapy is effective in lowering A1C in individuals diagnosed with prediabetes.
Five Takeaways for a Diet that Can Help Reverse Prediabetes
- Avoid sugar. Put simply, consuming sugar is the fastest way to raise your blood sugar. Whether it’s added or natural, plain table sugar or the fanciest organic honey, sugars break down to glucose easily.
Eliminating added sugar as best you can means reading labels, as there are dozens of types hiding in everything from ketchup to energy bars. But it’s not just added sugar—foods like fruit juices also pack a big glucose punch.
Note that natural sweeteners like stevia and monk fruit can be good alternatives in moderation; artificial sweeteners like Splenda and Equal have mixed research and may hurt metabolic health over the long term.
- Avoid processed grains and foods. Research found that ultra-processed foods made up 60% of the calories Americans consumed between 2007-2012. These foods have been broken down, stripped of nutrients like fiber, vitamins, and minerals, and combined with excess fat, salt, and sugar. They can include packaged junk food like chips and cereal and seemingly “healthy” foods like energy bars and drinks. The more processed the food, the more likely it is to cause a quick rise in glucose. This includes anything made with refined grains and flour, like white bread, tortillas, crackers, or bagels, which your body will break down quickly, leading to a blood sugar spike.Instead, try to eat:
- Low-carbohydrate vegetables (e.g., greens, broccoli, cauliflower, zucchini, Brussels sprouts)
- Fiber and protein-rich foods like beans, other legumes (e.g., lentils), nuts, and seeds
- Fats in their whole-food form like nuts, seeds, avocado, coconut, and olives
- Eat fiber. Studies show that high amounts of fiber are associated with lower post-meal blood sugar spikes and glycemic variability. Aim for around 50g a day; beans, legumes, nuts, seeds, vegetables, and some fruits (including kiwi, raspberries, blackberries, pomegranate, guava, and avocado) are the best sources.
- Pair carbs with fat, fiber, or protein, and avoid “naked carbs.” Research shows that eating carbs with fat, fiber, or protein can help blunt a blood sugar spike by slowing the rate your body absorbs and processes the carbohydrate.
If you eat an apple, pair it with nut butter or put it in a chia seed pudding (high fiber and healthy fats). If you have a sweet potato, add tahini, olive oil, flax seeds, or nuts—plus some protein.
- Ensure you’re getting micronutrients. Vitamins, minerals, and antioxidants play a vital role in ensuring that our cellular machinery runs smoothly. Eating a variety of high-quality whole foods from natural sources is an excellent way to get essential micronutrients.
Conclusion: Can Prediabetes Be Reversed Permanently?
Yes, but doing so relies on consistently making choices that support the physiology of insulin sensitivity. This includes supporting the body with quality food, consistent movement and exercise to improve muscle insulin sensitivity and glucose disposal, optimal sleep, stress management, and overcoming poor health habits, such as smoking. Overall, metabolic health is something that you can strongly impact with daily choices, even if you have genetic risk factors for prediabetes or diabetes.