Prediabetes: The Complete Guide to Blood Sugar, Insulin Resistance, Diet, Exercise and Preventing Type 2 Diabetes

Prediabetes means your blood sugar is higher than normal but not yet high enough to meet the diagnostic criteria for diabetes. It is common, often has no obvious symptoms, and increases the risk of developing type 2 diabetes and cardiovascular disease.

But prediabetes is not a prediction that you will definitely develop diabetes.

For many people, it is an opportunity to identify metabolic problems early and make changes that can substantially reduce their risk. Losing a modest amount of weight when appropriate, becoming more physically active, improving food quality, and participating in a structured diabetes-prevention program can all help. The CDC and NIDDK specifically highlight approximately 5–7% weight loss and at least 150 minutes of moderate physical activity per week as evidence-based prevention targets.

This guide explains what prediabetes is, what causes it, how it is diagnosed, what insulin resistance has to do with it, what to eat, how to exercise, whether carbohydrates need to be eliminated, how weight loss affects metabolic health, what medications and supplements can—and cannot—do, and how to build a practical long-term plan.

Medical disclaimer: This article is educational and does not diagnose or treat an individual. If you have abnormal blood-glucose results, symptoms of diabetes, or other medical conditions, discuss your results and treatment options with a qualified healthcare professional.

Prediabetes at a Glance

1. What Is Prediabetes?

Prediabetes is a metabolic condition in which blood glucose levels are higher than normal but not yet high enough to be classified as diabetes.

Glucose, commonly called blood sugar, is an important source of energy. When you eat carbohydrates, digestion breaks many of them down into glucose. That glucose enters your bloodstream.

Your pancreas produces insulin in response.

Insulin acts as a signal that helps glucose move from the bloodstream into cells, where it can be used for energy or stored.

When the system works properly, blood glucose is tightly regulated.

Prediabetes can develop when the body becomes less responsive to insulin.

This is known as insulin resistance.

Initially, the pancreas may compensate by producing more insulin. This can help keep glucose within a relatively normal range.

Over time, however, the body’s ability to compensate may become insufficient.

Blood glucose begins to rise.

That progression can look roughly like this:

But this is not an inevitable one-way progression.

Lifestyle changes can interrupt or slow the process, and some people with prediabetes return to normal glucose levels.

2. What Is Insulin Resistance?

Insulin resistance is one of the central concepts behind prediabetes.

Imagine insulin as a key.

The key signals a muscle cell to take glucose out of the bloodstream.

When insulin sensitivity is good, the signal works efficiently.

When insulin resistance develops, the same amount of insulin produces less of an effect.

The body may compensate by producing more insulin.

For a while:

More insulin → glucose remains relatively controlled

Eventually:

Insulin resistance + insufficient compensation → blood glucose rises

This is why someone can have significant metabolic dysfunction before their fasting glucose or A1C crosses the diabetes threshold.

Insulin resistance can involve several tissues, including skeletal muscle, liver, and adipose tissue.

The liver is particularly important because it produces glucose.

When insulin is working properly, it helps suppress unnecessary glucose production by the liver.

With insulin resistance, this regulation can become impaired.

3. What Causes Prediabetes?

There is no single cause of prediabetes.

It usually develops from a combination of genetic, metabolic, environmental, and lifestyle factors.

Important risk factors include:

• Excess body fat
• Visceral fat
• Physical inactivity
• Family history of diabetes
• Increasing age
• Certain ethnic backgrounds
• Previous gestational diabetes
• Polycystic ovary syndrome
• High blood pressure
• Abnormal cholesterol or triglycerides
• Certain medications
• Poor sleep
• Diet quality
• Other metabolic conditions

The USPSTF recommends screening asymptomatic adults ages 35–70 who have overweight or obesity and recommends preventive interventions for those found to have prediabetes. ADA guidance also recommends risk-based testing in adults with overweight or obesity and additional risk factors, with a lower BMI threshold for Asian American adults.

Importantly, prediabetes is not simply a consequence of eating sugar.

A person’s genetic susceptibility, body composition, physical activity, sleep, overall dietary pattern, and other health conditions can all contribute.

4. What Are the Symptoms of Prediabetes?

One of the most important things to understand about prediabetes is that you may not feel anything unusual.

Prediabetes frequently has no obvious symptoms.

Some people may report:

• Increased hunger
• Fatigue
• Difficulty losing weight
• Increased thirst
• Frequent urination
• Brain fog
• Changes in energy

But these symptoms are nonspecific.

They do not establish a diagnosis.

Someone can feel completely healthy and still have prediabetes.

That is why appropriate blood-glucose testing is important for people at increased risk.

5. Prediabetes vs. Diabetes

Prediabetes and diabetes exist on a metabolic continuum, but the diagnostic thresholds are different.

For A1C, the CDC identifies:

Other diagnostic tests include fasting plasma glucose and the oral glucose tolerance test.

The exact interpretation should be based on the applicable diagnostic guidelines and clinical context.

A single abnormal result does not necessarily tell the entire story.

Certain conditions can also affect A1C accuracy, including some blood disorders, severe anemia, kidney disease, liver disease, pregnancy, blood loss, and certain medications.

If your test result is unexpected, discuss it with your healthcare professional rather than attempting to diagnose yourself from the number alone.

6. Why A1C Matters

A1C, or hemoglobin A1C, estimates average blood glucose over approximately the previous two to three months.

It is useful because it provides a longer-term picture than a single glucose measurement.

However, A1C does not show everything.

Two people can have the same A1C while having somewhat different glucose patterns.

A1C also does not tell you:

• What your glucose was immediately after a particular meal
• How much your glucose fluctuates during the day
• What foods affect you most
• How exercise changes your glucose

And A1C can be affected by certain medical conditions.

That is why glucose results should be interpreted in context.

7. Can Prediabetes Be Reversed?

The word reversal needs some nuance.

Some people with prediabetes can bring their glucose measurements back into the normal range.

That is an important and achievable outcome for some individuals.

But normal glucose today does not necessarily mean a person has permanently eliminated their underlying risk.

If the contributing factors return, glucose levels may rise again.

A better way to think about prediabetes is:

Identify the metabolic problem → address modifiable risk factors → monitor → maintain the improvements.

The objective is long-term metabolic health rather than a temporary change in a laboratory value.

8. How Much Does Weight Loss Help?

Weight loss is one of the most well-established interventions for people with overweight or obesity who are at high risk of type 2 diabetes.

The CDC recommends a modest target of approximately 5–7% of starting body weight when appropriate. For someone weighing 200 pounds, that is approximately 10–14 pounds.

The 2026 ADA Standards similarly recommend aiming for at least 5–7% weight reduction in adults with overweight or obesity at high risk for type 2 diabetes.

More weight loss may provide additional metabolic benefits for some people, but the appropriate target depends on the individual.

And weight is not the only important metric.

Someone may improve:

• Waist circumference
• Fitness
• Blood pressure
• Triglycerides
• Insulin sensitivity
• Glucose control

without dramatic changes on the scale.

9. Why Visceral Fat Matters

Not all body fat behaves identically.

Subcutaneous fat is stored under the skin.

Visceral fat is stored around internal organs.

Excess visceral fat is associated with insulin resistance and cardiometabolic risk.

Fat accumulation in the liver and other tissues can also be metabolically important.

This is one reason waist circumference and body composition can sometimes provide information that body weight alone cannot.

However, waist measurements are not diagnostic by themselves.

For how fasting and calorie reduction affect visceral fat, see section 37.

10. What Should You Eat If You Have Prediabetes?

There is no single “prediabetes diet.”

This is an important point.

The 2026 ADA Standards state that there is no ideal percentage of calories that must come from carbohydrates, protein, and fat for diabetes prevention. Instead, the macronutrient balance should be individualized according to eating patterns, preferences, nutritional needs, and metabolic goals.

Evidence-supported patterns can include:

• Mediterranean-style eating
• Lower-carbohydrate approaches
• Plant-forward diets
• DASH-style eating
• Other minimally processed whole-food approaches

The common theme is food quality.

11. Foods to Eat More Often

A metabolic-health-focused eating pattern can emphasize:

Non-starchy vegetables

Examples:

• Broccoli
• Cauliflower
• Spinach
• Kale
• Green beans
• Peppers
• Mushrooms
• Cabbage
• Cucumbers
• Tomatoes
• Zucchini
• Eggplant

Protein-rich foods

Examples:

• Fish
• Chicken
• Eggs
• Greek yogurt
• Cottage cheese
• Tofu
• Tempeh
• Beans
• Lentils
• Lean meats

Fiber-rich foods

Examples:

• Vegetables
• Beans
• Lentils
• Oats
• Whole grains
• Nuts
• Seeds
• Whole fruit

Healthy fats

Examples:

• Olive oil
• Nuts
• Seeds
• Avocado
• Fatty fish

ADA’s 2026 nutrition recommendations emphasize nonstarchy vegetables, whole fruit, legumes, lean proteins, whole grains, nuts and seeds, and appropriate dairy or nondairy alternatives, while minimizing sugar-sweetened beverages, sweets, refined grains, and highly processed foods.

12. Do You Need to Eliminate Carbohydrates?

No.

Carbohydrates are not inherently unhealthy.

The more useful questions are:

What carbohydrate?

How much?

How processed is it?

What is eaten with it?

How does the person’s body respond?

A bowl of sugary cereal and a meal containing lentils, vegetables, and a modest amount of whole grain are both sources of carbohydrate, but they are not nutritionally equivalent.

For some people, reducing carbohydrates substantially can make blood-glucose management easier.

For others, a Mediterranean-style approach with high-quality carbohydrates works well.

Current ADA guidance does not require a single carbohydrate percentage or one universal diet.

13. What About Rice, Bread, Pasta and Potatoes?

These foods do not automatically need to disappear from your diet.

Instead, consider:

Portion

A large serving of starch can have a very different metabolic effect from a smaller serving.

Quality

Less-refined options may provide more fiber and nutrients.

Meal composition

Combining carbohydrate with protein, vegetables, and fiber can change the overall meal response.

Individual response

People differ.

If you monitor glucose, you may learn that certain meals affect you differently from what you expected.

The goal is not to create a list of “forbidden foods.”

The goal is to develop a sustainable eating pattern that supports metabolic health.

14. Are Oats Good for Prediabetes?

Oats can fit into a healthy eating pattern for many people with prediabetes.

They provide fiber, including beta-glucan.

However, oats are still a carbohydrate-containing food.

Portion and preparation matter.

A bowl of minimally processed oats combined with protein, seeds, nuts, and unsweetened yogurt is nutritionally different from a heavily sweetened instant-oatmeal product.

A practical oatmeal combination might include:

• Oats
• Chia seeds
• Ground flaxseed
• Greek yogurt
• Nuts
• Berries
• Cinnamon

If you are monitoring glucose, your own response can help determine whether a particular portion works well for you.

15. Are Beans and Lentils Good for Prediabetes?

Legumes are particularly useful foods to consider.

Beans, chickpeas, and lentils provide:

• Fiber
• Plant protein
• Micronutrients
• Complex carbohydrates

Their combination of protein and fiber can make them more filling than many refined carbohydrate foods.

Legumes can therefore fit well into Mediterranean, plant-forward, and other metabolic-health-focused eating patterns.

They do contain carbohydrates, so portion still matters for someone specifically managing carbohydrate intake.

16. What About Fruit?

Whole fruit can be part of a healthy eating pattern.

Fruit provides:

• Fiber
• Vitamins
• Minerals
• Polyphenols and other bioactive compounds

Whole fruit should generally not be treated as equivalent to sugar-sweetened beverages.

Fruit juice is different because it is much easier to consume a large quantity of carbohydrate quickly and generally contains less intact fiber than whole fruit.

For most people, the better question is not:

“Can I eat fruit?”

It is:

“How does whole fruit fit into my overall diet?”

17. Sugar-Sweetened Beverages: One of the Easiest Targets

If you want one simple nutrition change, reducing sugary drinks can be a high-impact starting point.

Examples include:

• Regular soda
• Sweet tea
• Sugar-sweetened coffee drinks
• Energy drinks containing sugar
• Fruit drinks with added sugar

Liquid calories can be easy to consume without producing the same satiety as solid food.

Replacing sugary drinks with water or unsweetened beverages is a straightforward strategy recommended by NIDDK’s diabetes-prevention guidance.

18. Protein and Prediabetes

Protein plays several roles in a healthy diet.

It supports:

• Muscle maintenance
• Satiety
• Recovery from exercise
• Overall nutritional adequacy

Good options include:

• Fish
• Chicken
• Eggs
• Greek yogurt
• Cottage cheese
• Tofu
• Tempeh
• Beans
• Lentils

Protein should not be viewed as a magic solution for insulin resistance.

Rather, it is one component of a balanced eating pattern.

19. Fiber and Prediabetes

Fiber is particularly valuable because it can improve diet quality and help with fullness.

High-fiber foods include:

• Vegetables
• Beans
• Lentils
• Whole grains
• Oats
• Nuts
• Seeds
• Whole fruit

A high-fiber eating pattern can also make it easier to replace highly processed foods.

Increase fiber gradually if your current intake is low, especially if you experience digestive symptoms.

20. Exercise: One of the Most Powerful Tools

Exercise is not merely a calorie-burning activity.

Muscles are major users of glucose.

Regular physical activity improves insulin sensitivity and can help with weight management, cardiovascular fitness, and overall metabolic health.

The CDC and ADA recommend a target of at least 150 minutes per week of moderate-intensity activity for diabetes prevention.

That could be:

30 minutes × 5 days

But it does not have to be performed that way.

You can divide activity into shorter sessions.

21. Walking After Meals

A simple strategy is taking a walk after eating.

Even short periods of movement after meals can help increase glucose utilization.

Walking also has a major advantage:

It is accessible.

You don’t need:

• A gym
• Expensive equipment
• Special clothing
• Advanced fitness

A 10–15 minute walk after meals can be a practical habit for many people.

ADA guidance also supports breaking up prolonged sedentary time because this can reduce post-meal glucose levels.

22. Strength Training for Prediabetes

Resistance training deserves a place in a diabetes-prevention plan.

Muscle tissue is metabolically active and plays an important role in glucose disposal.

Strength training can include:

• Squats
• Lunges
• Push-ups
• Pull-ups
• Rows
• Shoulder presses
• Resistance-band exercises
• Dumbbells
• Kettlebells
• Machine-based exercises

You don’t need to become a bodybuilder.

The goal is to progressively challenge major muscle groups.

For beginners, two or three resistance-training sessions per week can be a reasonable starting framework, with the exact plan individualized to fitness level and medical circumstances.

23. What About HIIT?

High-intensity interval training can improve fitness and metabolic health, but it is not mandatory.

A person who consistently walks, performs resistance training, and reduces sedentary time can still make meaningful progress.

For someone new to exercise, starting with moderate activity may be more practical than immediately adopting high-intensity workouts.

The best exercise program is one that is safe, appropriate, and sustainable.

24. Sleep and Prediabetes

Metabolic health extends beyond diet and exercise.

Sleep affects:

• Appetite
• Food choices
• Energy
• Exercise capacity
• Stress
• Hormonal regulation
• Insulin sensitivity

Poor sleep can make healthy behaviors harder to maintain.

Aim for consistent sleep and address persistent sleep problems.

If you snore heavily, experience witnessed pauses in breathing, wake unrefreshed, or experience significant daytime sleepiness, discuss possible sleep-disordered breathing with a healthcare professional.

25. Stress and Metabolic Health

Stress does not mean that your blood sugar will automatically become abnormal.

But chronic stress can affect behaviors and physiology that influence metabolic health.

For example, stress may contribute to:

• Poor sleep
• Less physical activity
• Increased appetite
• Emotional eating
• Greater consumption of highly processed foods
• Reduced adherence to healthy routines

Stress management therefore belongs in a sustainable prevention strategy.

Useful approaches can include:

• Walking
• Exercise
• Meditation
• Breathing exercises
• Social connection
• Time outdoors
• Hobbies
• Structured routines
• Professional mental-health support when appropriate

26. Prediabetes and Fatty Liver

Prediabetes and metabolic dysfunction can occur alongside fatty liver disease.

The terminology has evolved, and metabolic dysfunction-associated steatotic liver disease (MASLD) is now commonly used for a major category of fatty liver disease.

Insulin resistance, excess visceral fat, abnormal triglycerides, and glucose dysregulation can cluster together.

Improving overall metabolic health—including appropriate weight loss, physical activity, and dietary quality—can benefit liver health.

If you have been told you have fatty liver, discuss appropriate evaluation and monitoring with your healthcare professional.

For how intermittent fasting and calorie reduction can lower liver fat, see section 37.

27. Prediabetes and Cholesterol

Prediabetes can occur alongside other cardiovascular risk factors.

These may include:

• High LDL cholesterol
• High triglycerides
• Low HDL cholesterol
• High blood pressure
• Excess body weight

ADA’s 2026 Standards specifically note that prediabetes is associated with increased cardiovascular risk and recommend attention to modifiable cardiovascular risk factors.

This is important because preventing diabetes should not be the only objective.

A complete metabolic-health strategy should consider cardiovascular risk as well.

28. Prediabetes and Blood Pressure

High blood pressure frequently overlaps with metabolic disease.

If you have prediabetes, it is useful to know your blood pressure rather than focusing exclusively on glucose.

A comprehensive health strategy should address:

glucose + blood pressure + lipids + body composition + physical activity + nutrition

rather than treating each measurement as completely separate.

29. Should You Use a Continuous Glucose Monitor?

Continuous glucose monitors, or CGMs, measure glucose through a sensor placed under the skin.

They can provide detailed information about glucose patterns.

A CGM may show:

• Overnight patterns
• Post-meal rises
• Response to exercise
• Daily glucose variability

However, CGM data can be fascinating without necessarily being clinically necessary.

A glucose rise after eating is not automatically dangerous.

Glucose naturally changes throughout the day.

CGM devices also have measurement limitations and are not a substitute for diagnostic testing when evaluating prediabetes or diabetes.

If you are considering CGM for metabolic-health tracking without diagnosed diabetes, discuss whether it is appropriate with a healthcare professional.

30. Should You Take Metformin for Prediabetes?

Metformin is a medication used primarily to treat type 2 diabetes and is sometimes considered for diabetes prevention in selected people at particularly high risk.

The decision is individualized.

Factors such as:

• Age
• BMI
• Degree of glucose elevation
• Pregnancy history
• Other medical conditions
• Kidney function
• Personal preferences

can influence the decision.

NIDDK includes metformin among options people can discuss with their healthcare team as part of diabetes prevention.

Medication should not be started, stopped, or changed based solely on an internet article.

31. What About GLP-1 and Other Weight-Loss Medications?

Modern obesity medications can produce substantial weight loss and can improve several metabolic markers.

For people with obesity or other qualifying conditions, these medications may be considered as part of comprehensive medical care.

However, they are not appropriate for everyone.

Potential considerations include:

• Eligibility
• Cost
• Side effects
• Contraindications
• Long-term treatment
• Weight regain after discontinuation
• Individual health goals

Medication decisions should be made with a healthcare professional.

They should complement—not necessarily replace—long-term nutrition, physical activity, sleep, and behavioral strategies.

32. What About Supplements?

The supplement industry contains many claims about “reversing insulin resistance.”

Be cautious.

Commonly promoted supplements include:

• Berberine
• Magnesium
• Vitamin D
• Cinnamon
• Omega-3 fatty acids
• Chromium
• Psyllium
• Probiotics
• Various herbal products

Some have evidence for specific outcomes or in specific populations.

That is different from proving that they prevent diabetes or reverse prediabetes.

A supplement should not be considered a substitute for evidence-based lifestyle intervention or indicated medication.

Also remember that “natural” does not automatically mean safe.

Supplements can interact with medications and can cause adverse effects.

33. What Is the Best Diet for Prediabetes?

There is no universal winner.

The most useful eating pattern is one that:

1. Improves overall food quality
2. Is nutritionally adequate
3. Helps achieve an appropriate energy balance
4. Fits your preferences and culture
5. Can be maintained
6. Supports your metabolic goals

Current ADA guidance supports multiple dietary patterns rather than a single mandatory diet. Mediterranean, plant-forward, DASH-style, and lower-carbohydrate patterns can all be appropriate depending on the person.

This is why “Which diet is best?” is often the wrong question.

A better question is:

“Which evidence-based eating pattern can I follow consistently while improving my health?”

34. A Simple Prediabetes Meal Formula

If you don’t want to count every calorie or carbohydrate, start with meal structure.

Step 1: Choose protein

Examples:

• Fish
• Chicken
• Eggs
• Greek yogurt
• Tofu
• Beans
• Lentils

Step 2: Add vegetables

Aim for a generous serving of non-starchy vegetables.

Step 3: Add fiber-rich carbohydrate if desired

Examples:

• Lentils
• Beans
• Oats
• Whole grains
• Whole fruit

Step 4: Add healthy fat

Examples:

• Nuts
• Seeds
• Olive oil
• Avocado

Step 5: Adjust portions

If weight loss is an objective, total energy intake still matters.

35. Example Prediabetes-Friendly Meals

These are examples rather than prescribed diets.

Breakfast

Option 1

Oatmeal + chia + ground flax + Greek yogurt + berries

Option 2

Eggs + vegetables + avocado

Option 3

Greek yogurt + nuts + berries + seeds

Lunch

Grilled chicken + large vegetable salad + lentils

Dinner

Salmon + roasted vegetables + beans

Vegetarian dinner

Tofu + mixed vegetables + lentils

Snack

Apple + small serving of nuts

Another snack

Plain Greek yogurt + berries

The goal is to create meals that are satisfying and nutritionally dense rather than simply labeling individual foods as “good” or “bad.”

36. Eating at Restaurants

Restaurant meals can make metabolic goals harder—but you do not have to stop eating out.

Try:

Before ordering

Look for:

• Grilled
• Roasted
• Steamed
• Baked

rather than foods that are heavily fried or breaded.

Build the meal

Choose:

Protein + vegetables + appropriate carbohydrate

Watch liquid calories

Water or unsweetened beverages can be easier choices than sugar-sweetened drinks.

Control portions

Restaurant portions can be much larger than what you would serve yourself at home.

Consider eating part of the meal and saving the remainder.

37. Intermittent Fasting, Insulin Sensitivity, Fatty Liver and Visceral Fat

Intermittent fasting means cycling between periods of eating and periods of not eating, or eating very little.

It is one of the most talked-about approaches for blood sugar, and one of the most misunderstood.

The short version: fasting can improve insulin sensitivity, mainly by helping people eat less and lose fat from the liver and from around the organs. In most head-to-head trials it works about as well as an ordinary calorie-reduced diet, not dramatically better. It is a useful tool, not a requirement.

What happens in your body during a fast

After you eat, insulin rises. It moves glucose into your cells and tells the body to store energy.

As the hours pass without food, insulin falls. The liver releases stored glucose (glycogen) to keep blood sugar steady, and fat cells start releasing fat to be used for fuel.

After roughly 12 hours or more, the body leans increasingly on fat, and the liver begins making small amounts of ketones. Researchers sometimes call this the “metabolic switch.”

Regular stretches of low insulin give stored fat, including fat in the liver and around the organs, a chance to be used rather than added to.

Can fasting improve insulin sensitivity?

It can. How much depends largely on what happens to calories, weight and body fat.

• Early time-restricted eating: In a small, tightly controlled trial, men with prediabetes who ate all their meals within a 6-hour window ending by mid-afternoon for 5 weeks had better insulin sensitivity, a better insulin response and lower blood pressure than when they ate across 12 hours. Their weight did not change (Sutton et al., 2018).
• Longer trials: When time-restricted eating is compared with an ordinary calorie-reduced diet over 12 months, weight, waist size, body fat and metabolic risk factors improve by similar amounts (Liu et al., 2022).
• Alternate-day fasting and 5:2: Both lead to weight loss and to improvements in insulin and glucose broadly similar to daily calorie restriction (Trepanowski et al., 2017; Carter et al., 2018).

In other words, meal timing may add a modest benefit, especially when eating is shifted earlier in the day. The biggest driver is usually the loss of body fat, particularly fat in the liver and around the organs.

Types of fasting

How fasting links fatty liver, visceral fat, inflammation and insulin

Visceral fat is not passive. It releases free fatty acids and inflammatory signals such as interleukin-6 (IL-6) and TNF-alpha. Because blood from visceral fat drains straight to the liver, the liver receives a steady flow of both.

A fatty liver resists insulin. When fat builds up inside liver cells, insulin has a harder time telling the liver to stop releasing glucose. Fasting blood sugar rises as a result.

Low-grade inflammation spreads the problem. Inflammatory signals interfere with insulin signaling in the liver and muscles, so the body needs more insulin to do the same job.

The chain can run in reverse. When liver fat and visceral fat fall, fatty acids and inflammatory signals decrease, and the liver and muscles respond better to insulin. In people with type 2 diabetes, losing liver fat has been closely linked with blood sugar returning toward normal (Taylor et al., 2018).

Fasting and fatty liver (MASLD)

Fatty liver and prediabetes often travel together (see section 26).

In a 12-month trial of adults with obesity and fatty liver, eating within an 8-hour window plus calorie restriction reduced liver fat substantially, but no more than the same calorie restriction without a time window (Wei et al., 2023).

In a 3-month trial, alternate-day fasting combined with aerobic exercise reduced liver fat and improved insulin sensitivity. Fasting alone or exercise alone did not produce the same improvement (Ezpeleta et al., 2023).

The practical lesson: for fatty liver, fasting works best as a way to reduce total calories, paired with regular physical activity.

People with advanced liver disease (cirrhosis) are generally advised not to go long periods without food. Check with your liver specialist before trying any fasting plan.

Fasting and visceral fat

Trials that measure visceral fat directly with MRI show that intermittent calorie restriction, such as 5:2, reduces both visceral fat and liver fat, by about the same amount as daily calorie restriction that produces similar weight loss (Schübel et al., 2018).

There is no good evidence that fasting “targets” belly fat on its own. Visceral fat tends to fall early with any sustained calorie deficit, and exercise helps further (see section 20 and section 22).

What about inflammation?

Some fasting studies report lower inflammatory markers such as C-reactive protein (CRP), but results are inconsistent.

The improvements tend to follow losses of weight and body fat rather than the fasting itself.

What the evidence does not show

• That fasting is necessary to improve prediabetes.
• That fasting is clearly better than a well-planned, calorie-reduced eating pattern over the long term.
• That longer fasts are better. Multi-day fasts carry more risk and should be medically supervised.
• That fasting is right for everyone. Long-term data are still limited. One preliminary observational report in 2024 linked very short eating windows with higher cardiovascular death. It cannot prove cause, but it is a reason for balance.

How to try fasting sensibly

1. Start with a 12-hour overnight fast. After dinner, have only water, black coffee or plain tea until breakfast.
2. Move to 14:10 if it feels comfortable, then consider 16:8 or an earlier window.
3. Shift eating earlier where you can. Finishing your last meal 2–3 hours before bed is a practical version of early time-restricted eating.
4. Break the fast with protein and fiber, using the meal formula in section 34.
5. Keep protein adequate and keep strength training so that you lose fat, not muscle.
6. Drink water, and notice dizziness, headaches, poor sleep or overeating later in the day.
7. Judge it after about 3 months: A1C, fasting glucose, waist, weight, energy and whether you can keep it up.

Talk to your healthcare professional before fasting if you:

• take insulin or a sulfonylurea (such as glipizide, glimepiride or gliclazide), which can cause dangerously low blood sugar during a fast;
• take an SGLT2 inhibitor (such as empagliflozin or dapagliflozin), which can raise the risk of ketoacidosis during longer fasts, or other medicines for diabetes, blood pressure or heart conditions;
• are pregnant or breastfeeding, under 18, underweight or frail;
• have a history of an eating disorder;
• have cirrhosis, kidney disease or another significant medical condition.

Fasting helps insulin sensitivity when it helps you lose liver fat and visceral fat. Choose the pattern you can keep, not the most extreme one.

38. Is Eating Two Meals a Day Better?

Not necessarily.

Some people prefer two larger meals.

Others do better with three meals.

Some use smaller meals or snacks.

There is no universal requirement that someone with prediabetes must eat a particular number of times per day.

Meal frequency should support:

• Nutrition
• Hunger control
• Activity
• Sleep
• Medication schedules
• Personal preferences
• Sustainable calorie intake

39. The 12-Week Prediabetes Improvement Plan

A structured plan can make the process easier.

Weeks 1–2: Measure and Understand

Start by establishing a baseline.

Track:

• Weight
• Waist circumference
• Activity
• Typical meals
• Sleep
• A1C
• Fasting glucose if available
• Blood pressure
• Lipid profile when appropriate

Do not attempt to change everything simultaneously.

Weeks 3–4: Remove the Biggest Problems

Focus on high-impact changes.

Examples:

• Eliminate or substantially reduce sugary drinks
• Reduce frequent desserts
• Reduce ultra-processed foods
• Increase vegetables
• Add protein to meals
• Start daily walking

Weeks 5–6: Increase Movement

Work toward approximately:

150 minutes of moderate activity per week

Add resistance training two or more times per week if appropriate.

Break up long periods of sitting.

Weeks 7–8: Improve Meal Structure

Build meals around:

Protein + vegetables + fiber + appropriate carbohydrate + healthy fat

Experiment with portions.

Notice which meals are most satisfying.

Weeks 9–10: Improve Sleep and Recovery

Focus on:

• Consistent bedtime
• Adequate sleep opportunity
• Reduced late-night eating
• Regular physical activity
• Stress management

Weeks 11–12: Make the Plan Sustainable

Review what worked.

Keep the habits that were realistic.

Modify those that were not.

Avoid the temptation to pursue a perfect diet for two weeks and then abandon it.

The objective is a lifestyle you can maintain for years.

40. What Should You Track?

A simple metabolic-health dashboard can include:

Daily or weekly

• Weight trend
• Steps/activity
• Exercise
• Sleep
• Major dietary habits

Periodically

• A1C
• Fasting glucose
• Blood pressure
• Lipid profile
• Waist circumference

ADA 2026 recommends that people with prediabetes be monitored for development of diabetes at least annually, with testing frequency adjusted according to individual risk.

41. Don’t Become Obsessed With Daily Glucose

A common mistake is to turn metabolic health into a competition with a glucose meter.

Glucose naturally changes.

It can be affected by:

• Food
• Exercise
• Stress
• Sleep
• Illness
• Hormones
• Hydration
• Timing

A single reading does not define your health.

Long-term trends are generally more meaningful.

42. Common Prediabetes Myths

43. When Should You Talk With a Healthcare Professional?

Seek medical evaluation if you:

• Have an abnormal glucose or A1C result
• Have symptoms suggestive of diabetes
• Have a strong family history of diabetes
• Have obesity or significant excess abdominal fat
• Have high blood pressure
• Have abnormal triglycerides or cholesterol
• Have fatty liver disease
• Have a history of gestational diabetes
• Have PCOS
• Take medications that can affect glucose
• Are unsure how frequently you should be tested

You should not rely on an internet guide to diagnose yourself.

44. Prediabetes and Cardiovascular Health

Prediabetes deserves attention even if diabetes never develops.

Why?

Because metabolic risk factors can cluster.

Someone with prediabetes may also have:

• Hypertension
• Dyslipidemia
• Visceral adiposity
• Fatty liver
• Physical inactivity

ADA’s 2026 guidance recognizes the association between prediabetes and increased cardiovascular risk and recommends addressing modifiable cardiovascular risk factors.

Therefore, a complete prevention strategy should ask more than:

“What’s my blood sugar?”

It should also ask:

“What is my overall cardiometabolic risk?”

45. What Does Success Look Like?

Success does not necessarily mean:

• A perfect diet
• Zero carbohydrates
• A particular body weight
• Never eating dessert
• Exercising every day
• Never having a high glucose reading

Success may look like:

• Your A1C improves
• Your waist circumference decreases
• You become stronger
• You walk more
• Your blood pressure improves
• Your triglycerides decrease
• You eat more vegetables and fiber
• You sleep better
• You maintain healthier habits
• Your risk of progressing to diabetes decreases

Think in terms of trends.

46. The Most Important Things You Can Do

If you remember only ten things from this guide, remember these:

47. Frequently Asked Questions

48. The Bottom Line

Prediabetes is a measurable sign that glucose regulation is becoming abnormal.

It is important—but it is also an opportunity.

The strongest evidence does not point toward one miracle food, one supplement, one fasting schedule, or one perfect exercise.

Instead, it points toward a collection of sustainable behaviors.

Eat a higher-quality diet.

Reduce highly processed foods and sugar-sweetened beverages.

Choose appropriate portions.

Include vegetables, legumes, whole foods, protein, fiber, nuts, seeds, and other nutrient-dense foods.

Move regularly.

Aim for at least 150 minutes of moderate physical activity each week.

Add resistance training.

Break up long periods of sitting.

Get adequate sleep.

Manage stress.

If you have overweight or obesity and are at high risk, even 5–7% weight loss can be meaningful.

And monitor your health over time.

The 2026 ADA Standards emphasize that diabetes prevention should be personalized rather than built around a single diet or intervention.

Most importantly, don’t wait until prediabetes becomes diabetes before taking metabolic health seriously.

Prediabetes is a signal. What you do with that signal matters.

Evidence-Based Sources

This article is based on the concepts contained in the original Prediabetes Guide material and updated against current major U.S. clinical and public-health sources.

• American Diabetes Association — Standards of Care in Diabetes 2026: prevention and delay of diabetes, nutrition, physical activity, weight management, and cardiovascular risk.
• CDC — Prediabetes and prevention of type 2 diabetes: testing, 5–7% weight-loss target, physical activity and the National Diabetes Prevention Program.
• CDC — A1C testing: diagnostic A1C thresholds and factors that can affect A1C accuracy.
• NIDDK — Preventing Type 2 Diabetes: weight management, physical activity, healthy eating, monitoring and prevention strategies.
• USPSTF — Screening for Prediabetes and Type 2 Diabetes: screening recommendations and risk factors.
• Sutton EF, et al. Cell Metabolism, 2018: early time-restricted feeding improved insulin sensitivity, blood pressure and oxidative stress without weight loss in men with prediabetes.
• Liu D, et al. New England Journal of Medicine, 2022: calorie restriction with or without time-restricted eating over 12 months.
• Trepanowski JF, et al. JAMA Internal Medicine, 2017: alternate-day fasting vs daily calorie restriction.
• Carter S, et al. JAMA Network Open, 2018: intermittent vs continuous energy restriction and A1C in type 2 diabetes.
• Wei X, et al. JAMA Network Open, 2023 (TREATY-FLD): time-restricted eating vs daily calorie restriction in fatty liver disease.
• Ezpeleta M, et al. Cell Metabolism, 2023: alternate-day fasting combined with aerobic exercise in fatty liver disease.
• Schübel R, et al. American Journal of Clinical Nutrition, 2018 (HELENA): intermittent vs continuous calorie restriction and MRI-measured visceral and liver fat.
• Taylor R, et al. Cell Metabolism, 2018: falling liver and pancreas fat and remission of type 2 diabetes.
• American Heart Association EPI|Lifestyle Scientific Sessions, 2024 (abstract): observational analysis of 8-hour time-restricted eating and cardiovascular death (preliminary).

Medical content note: Recommendations and diagnostic criteria can change. Readers should consult current clinical guidance and their healthcare professional for individualized decisions.