Diabetes is a chronic disease that affects millions of people worldwide. Uncontrolled cases can cause blindness, kidney failure, heart disease and other serious conditions.
Before diabetes is diagnosed, there is a period where blood sugar levels are high but not high enough to be diagnosed as diabetes. This is known as prediabetes.
It's estimated that up to 70% of people with prediabetes go on to develop type 2 diabetes. Fortunately, progressing from prediabetes to diabetes isn't inevitable (1).
Although there are certain factors you can't change — such as your genes, age or past behaviors — there are many actions you can take to reduce the risk of diabetes.
Here are 13 ways to avoid getting diabetes.
Your body rapidly breaks these foods down into small sugar molecules, which are absorbed into your bloodstream.
The resulting rise in blood sugar stimulates your pancreas to produce insulin, a hormone that helps sugar get out of the bloodstream and into your body's cells.
In people with prediabetes, the body's cells are resistant to insulin's action, so sugar remains high in the blood. To compensate, the pancreas produces more insulin, attempting to bring blood sugar down to a healthy level.
Over time, this can lead to progressively higher blood sugar and insulin levels, until the condition eventually turns into type 2 diabetes.
Many studies have shown a link between the frequent consumption of sugar or refined carbs and the risk of diabetes. What's more, replacing them with foods that have less of an effect on blood sugar may help reduce your risk (2, 3, 4, 5, 6).
A detailed analysis of 37 studies found that people with the highest intakes of fast-digesting carbs were 40% more likely to develop diabetes than those with the lowest intakes (7).
Summary: Eating foods high in refined carbs and sugar increases blood sugar and insulin levels, which may lead to diabetes over time. Avoiding these foods may help reduce your risk.
Performing physical activity on a regular basis may help prevent diabetes.
Exercise increases the insulin sensitivity of your cells. So when you exercise, less insulin is required to keep your blood sugar levels under control.
One study in people with prediabetes found that moderate-intensity exercise increased insulin sensitivity by 51% and high-intensity exercise increased it by 85%. However, this effect only occurred on workout days (8).
Many types of physical activity have been shown to reduce insulin resistance and blood sugar in overweight, obese and prediabetic adults. These include aerobic exercise, high-intensity interval training and strength training (9, 10, 11, 12, 13, 14).
Working out more frequently seems to lead to improvements in insulin response and function. One study in people at risk of diabetes found that burning more than 2,000 calories weekly via exercise was required to achieve these benefits (14).
Therefore, it's best to choose physical activity that you enjoy, can engage in regularly and feel you can stick with long-term.
Summary: Performing physical activity on a regular basis can increase insulin secretion and sensitivity, which may help prevent the progression from prediabetes to diabetes.
Water is by far the most natural beverage you can drink.
What's more, sticking with water most of the time helps you avoid beverages that are high in sugar, preservatives and other questionable ingredients.
Sugary beverages like soda and punch have been linked to an increased risk of both type 2 diabetes and latent autoimmune diabetes of adults (LADA).
LADA is a form of type 1 diabetes that occurs in people over 18 years of age. Unlike the acute symptoms seen with type 1 diabetes in childhood, LADA develops slowly, requiring more treatment as the disease progresses (15).
One large observational study looked at the diabetes risk of 2,800 people.
Those who consumed more than two servings of sugar-sweetened beverages per day had a 99% increased risk of developing LADA and a 20% increased risk of developing type 2 diabetes (16).
One 24-week study showed that overweight adults who replaced diet sodas with water while following a weight loss program experienced a decrease in insulin resistance and lower fasting blood sugar and insulin levels (19).
Summary: Drinking water instead of other beverages may help control blood sugar and insulin levels, thereby reducing the risk of diabetes.
Although not everyone who develops type 2 diabetes is overweight or obese, the majority are.
What's more, those with prediabetes tend to carry excess weight in their midsection and around abdominal organs like the liver. This is known as visceral fat.
One study of more than 1,000 people with prediabetes found that for every kilogram (2.2 lbs) of weight participants lost, their risk of diabetes reduced by 16%, up to a maximum reduction of 96% (25).
There are many healthy options for losing weight, including low-carb, Mediterranean, paleo and vegetarian diets. However, choosing a way of eating you can stick with long-term is key to helping you maintain the weight loss.
One study found that obese people whose blood sugar and insulin levels decreased after losing weight experienced elevations in these values after gaining back all or a portion of the weight they lost (26).
Summary: Carrying excess weight, particularly in the abdominal area, increases the likelihood of developing diabetes. Losing weight may significantly reduce the risk of diabetes.
Smoking has been shown to cause or contribute to many serious health conditions, including heart disease, emphysema and cancers of the lung, breast, prostate and digestive tract (27).
In an analysis of several studies totaling over one million people, smoking was found to increase the risk of diabetes by 44% in average smokers and 61% in people who smoked more than 20 cigarettes daily (30).
One study followed the risk of diabetes in middle-aged male smokers after they quit. After five years their risk had reduced by 13%, and after 20 years they had the same risk as people who had never smoked (31).
Researchers stated that even though many of the men gained weight after quitting, after several smoke-free years, their risk of diabetes was lower than if they'd continued smoking.
Summary: Smoking is strongly linked to the risk of diabetes, especially in heavy smokers. Quitting has been shown to reduce this risk over time.
Following a ketogenic or very-low-carb diet can help you avoid diabetes.
Although there are a number of ways of eating that promote weight loss, very-low-carb diets have strong evidence behind them.
In a 12-week study, prediabetic individuals consumed either a low-fat or low-carb diet. Blood sugar dropped by 12% and insulin dropped by 50% in the low-carb group.
In the low-fat group, meanwhile, blood sugar dropped by only 1% and insulin dropped by 19%. Thus, the low-carb diet had better results on both counts (35).
If you minimize your carb intake, your blood sugar levels won't rise very much after you eat. Therefore, your body needs less insulin to maintain your blood sugar within healthy levels.
What's more, very-low-carb or ketogenic diets may also reduce fasting blood sugar.
In a study of obese men with prediabetes who followed a ketogenic diet, average fasting blood sugar decreased from 118 to 92 mg/dl, which is within the normal range. Participants also lost weight and improved several other health markers (36).
For more info, check out this Guide to Healthy Low-Carb Eating With Diabetes.
Summary: Following a ketogenic or very-low-carb diet can help keep blood sugar and insulin levels under control, which may protect against diabetes.
Whether or not you decide to follow a low-carb diet, it's important to avoid large portions of food to reduce the risk of diabetes, especially if you are overweight.
Eating too much food at one time has been shown to cause higher blood sugar and insulin levels in people at risk of diabetes (37).
On the other hand, decreasing portion sizes may help prevent this type of response.
A two-year study in prediabetic men found that those who reduced food portion sizes and practiced other healthful nutrition behaviors had a 46% lower risk of developing diabetes than the men who made no lifestyle changes (38).
Another study looking at weight loss methods in people with prediabetes reported that the group practicing portion control lowered their blood sugar and insulin levels significantly after 12 weeks (39).
Summary: Avoiding large portion sizes can help reduce insulin and blood sugar levels and decrease the risk of diabetes.
It's important to avoid being sedentary if you want to prevent diabetes.
If you get no or very little physical activity, and you sit during most of your day, then you lead a sedentary lifestyle.
A large analysis of 47 studies found that people who spent the highest amount of time per day engaged in sedentary behavior had a 91% increased risk of developing diabetes (41).
Changing sedentary behavior can be as simple as standing up from your desk and walking around for a few minutes every hour.
Unfortunately, it can be hard to reverse firmly entrenched habits.
One study gave young adults at risk of diabetes a 12-month program designed to change sedentary behavior. Sadly, after the program ended, the researchers found that participants hadn't reduced how much time they sat (42).
Set realistic and achievable goals, such as standing while talking on the phone or taking the stairs instead of the elevator. Committing to these easy, concrete actions may be the best way to reverse sedentary tendencies.
Summary: Avoiding sedentary behaviors like excessive sitting has been shown to reduce your risk of getting diabetes.
Getting plenty of fiber is beneficial for gut health and weight management.
Fiber can be divided into two broad categories: soluble and insoluble. Soluble fiber absorbs water, whereas insoluble fiber does not.
In the digestive tract, soluble fiber and water form a gel that slows down the rate at which food is absorbed. This leads to a more gradual rise in blood sugar levels (47).
Most unprocessed plant foods contain fiber, although some have more than others. Check out this list of 22 high-fiber foods for many excellent sources of fiber.
Summary: Consuming a good fiber source at each meal can help prevent spikes in blood sugar and insulin levels, which may help reduce your risk of developing diabetes.
Vitamin D is important for blood sugar control.
Most health organizations recommend maintaining a vitamin D blood level of at least 30 ng/ml (75 nmol/l).
One study found that people with the highest blood levels of vitamin D were 43% less likely to develop type 2 diabetes than those with the lowest blood levels (49).
Another observational study looked at Finnish children who received supplements containing adequate levels of vitamin D.
Children who took the vitamin D supplements had a 78% lower risk of developing type 1 diabetes than children who received less than the recommended amount of vitamin D (50).
Controlled studies have shown that when people who are deficient take vitamin D supplements, the function of their insulin-producing cells improves, their blood sugar levels normalize and their risk of diabetes reduces significantly (51, 52).
Good food sources of vitamin D include fatty fish and cod liver oil. In addition, sun exposure can increase vitamin D levels in the blood.
However, for many people, supplementing with 2,000–4,000 IU of vitamin D daily may be necessary to achieve and maintain optimal levels.
Summary: Consuming foods high in vitamin D or taking supplements can help optimize vitamin D blood levels, which can reduce your risk of diabetes.
One clear step you can take to improve your health is to minimize your consumption of processed foods.
They're linked to all sorts of health problems, including heart disease, obesity and diabetes.
This may be partly due to the protective effects of whole foods like nuts, vegetables, fruits and other plant foods.
One study found that poor-quality diets that were high in processed foods increased the risk of diabetes by 30%. However, including nutritious whole foods helped reduce this risk (55).
Summary: Minimizing processed foods and focusing on whole foods with protective effects on health may help decrease the risk of diabetes.
Although water should be your primary beverage, research suggests that including coffee or tea in your diet may help you avoid diabetes.
Studies have reported that drinking coffee on a daily basis reduced the risk of type 2 diabetes by 8–54%, with the greatest effect generally seen in people with the highest consumption (56, 57, 58, 59, 60, 61).
Another review of several studies that included caffeinated tea and coffee found similar results, with the largest risk reduction in women and overweight men (62).
Coffee and tea have antioxidants known as polyphenols that may help protect against diabetes (63).
In addition, green tea contains a unique antioxidant compound called epigallocatechin gallate (EGCG) that has been shown to reduce blood sugar release from the liver and increase insulin sensitivity (64, 65).
Summary: Drinking coffee or tea may help reduce blood sugar levels, increase insulin sensitivity and reduce the risk of diabetes.
There are a few herbs that may help increase insulin sensitivity and reduce the likelihood of diabetes progression.
Curcumin is a component of the bright gold spice turmeric, which is one of the main ingredients in curries.
It has strong anti-inflammatory properties and has been used in India for centuries as part of Ayurvedic medicine.
In a controlled nine-month study of 240 prediabetic adults, among the group who took 750 mg of curcumin daily, no one developed diabetes. However, 16.4% of the control group did (69).
In addition, the curcumin group experienced an increase in insulin sensitivity and improved functioning of insulin-producing cells in the pancreas.
Berberine is found in several herbs and has been used in traditional Chinese medicine for thousands of years.
Studies have shown that it fights inflammation and lowers cholesterol and other heart disease markers (70).
In fact, a large analysis of 14 studies found that berberine is as effective at lowering blood sugar levels as metformin, one of the oldest and most widely used diabetes medications (74).
Because berberine works by increasing insulin sensitivity and reducing the release of sugar by the liver, it might theoretically help people with prediabetes avoid diabetes.
However, at this point there are no studies that have looked at this.
In addition, since its effects on blood sugar are so strong, it should not be used in conjunction with other diabetes medications unless authorized by a doctor.
Summary: The herbs curcumin and berberine increase insulin sensitivity, reduce blood sugar levels and may help prevent diabetes.
You have control over many of the factors that influence diabetes.
Rather than viewing prediabetes as a stepping stone to diabetes, it may be helpful to see it as a motivator for making changes that can help reduce your risk.
Eating the right foods and adopting other lifestyle behaviors that promote healthy blood sugar and insulin levels will give you the best chance at avoiding diabetes.