Prediabetes Explained

Understanding the changes leading up to diabetes and how to stop its progression

Prediabetes is a precursor to type 2 diabetes. It is characterized by slightly elevated blood glucose levels, impacting nearly 40% of the US population. It’s a manifestation of insulin resistance, but is typically asymptomatic, going unnoticed without regular testing. If untreated, prediabetes can evolve into type 2 diabetes. 

Worldwide, prediabetes is estimated to affect almost one billion people, representing a tremendous health burden. This is particularly true when one considers that most prediabetes cases will convert to diabetes within a few years unless successful interventions are implemented. 

Prediabetes

Prediabetes occurs when the cells of the body become less responsive to insulin signaling. This makes it more difficult to move blood glucose out of the bloodstream and into cells. The pancreas compensates by increasing its release of insulin. During prediabetes, blood sugar is not elevated enough to cause strong short-term symptoms. 

Diagnosis of prediabetes

During prediabetes, insulin levels rise, as does blood glucose. For prediabetes, fasting blood sugar between 100-125 mg/dL or Hemoglobin A1C between 5.7 and 6.4% are typical markers. 

Glucose tolerance testing also can reveal impaired glycemic control that signals prediabetes. 

Cells become increasingly resistant to the effects of insulin and blood sugar levels continue rising until type 2 diabetes develops.

Early signs of prediabetes

Elevations in insulin during prediabetes can result in weight gain, as well as a skin condition known as acanthosis nigricans. This sign consists of darkened skin in the armpits and back of the neck and is often accompanied by skin tags. 

A 2020 study published in the International Journal of Clinical Practice found that acanthosis nigricans was a specific and highly prevalent indicator of insulin resistance. They examined 320 patients, finding that the most commonly affected areas were the knuckles and the neck. 

Insulin has many functions in the body besides moving glucose out of the bloodstream and into cells. One of those functions is to act as a vasodilator, through the action of nitric oxide. This causes increased blood flow where needed. When cells begin to develop insulin resistance, circulation may become insufficient. One early warning sign of prediabetes is erectile dysfunction. 

An enlarged abdomen, or “central adiposity,” is also considered a warning sign of prediabetes. This correlates with increasing BMI, though waist-to-height ratio may be a more reliable indicator than BMI in many cases. 

The role of diet in prediabetes

There are three macronutrients in food: protein, fats, and carbohydrates. When we eat, we typically consume a combination of these macronutrients in varying proportions, which affect blood sugar levels differently. It's uncommon to consume just one macronutrient unless it's pure oil or sugar. Understanding this is crucial for managing prediabetes or type 2 diabetes through dietary strategies.

Carbohydrates break down into simple sugars such as glucose during digestion. This causes the most substantial spike in blood glucose levels. In healthy individuals, blood glucose levels return to normal relatively quickly. For individuals with prediabetes or type 2 diabetes, it takes longer to regulate blood glucose levels after a carbohydrate-rich meal. 

Proteins have a smaller and slower effect on blood glucose levels, while fats do not cause a rise in blood glucose levels. These facts are the basis for a scientifically sound diet to manage type 2 diabetes.

A meal featuring fatty meat and non-starchy vegetables differs significantly in macronutrient composition from a meal including bread, pasta, rice, and sweets. The former is primarily protein, fat, and fiber, with low digestible carbohydrates. 

Conversely, the latter contains high amounts of digestible carbohydrates but is lower in fat and protein. These two meals affect blood glucose levels very differently.

Treatment options for prediabetes

Medical providers typically treat prediabetes with Metformin. Patients who fail to make dietary changes and are likely to progress to diabetes are treated this way. It is estimated that 70% of those with prediabetes will progress to diabetes. Often, recommendations to lose weight or “eat better” are made, but these do not directly address the root cause—eating a high-carbohydrate diet.

A root-cause approach for treating prediabetes

Prediabetes can be treated with a low-carb diet to counter insulin resistance. Low-carb diets can effectively lower blood glucose and insulin levels. By reducing carbohydrate intake to a low-carb ketogenic level, blood sugar levels return to normal. 

Reverting to the initial high-carb diet often leads to a recurrence of elevated glucose and insulin levels. Sustaining a low-carb diet may be necessary to prevent a relapse into metabolic issues.

A low-carbohydrate diet lowers blood glucose load and decreases insulin requirement and production. This results in normalized fasting blood glucose levels and HbA1c. Carbohydrates prompt the strongest insulin response, while proteins have a mild effect, and fats require no insulin response. 

Food choices significantly influence insulin production, energy storage, and blood sugar levels. Seemingly healthy foods like brown rice contain large amounts of carbohydrates that can lead to significant blood sugar spikes, particularly for individuals with insulin resistance. 

Carbohydrate tolerance varies among individuals. Insulin-sensitive individuals need less insulin to process carbs, while those with low carbohydrate tolerance experience heightened insulin levels. This exacerbates insulin resistance and can promote diabetes.