Glucose intolerance, often called prediabetes, is reversible with the right combination of lifestyle changes and, in some cases, medication. The condition is defined by blood sugar levels that are elevated but not yet in the diabetic range: a fasting glucose of 100 to 125 mg/dL, a two-hour glucose tolerance test result of 140 to 199 mg/dL, or an A1c between 5.7% and 6.4%. The good news is that measurable improvements in insulin resistance can begin within as little as eight weeks of consistent effort.
Why Weight Loss Matters Most
Losing 5% to 10% of your body weight is the single most effective way to prevent glucose intolerance from progressing to type 2 diabetes. For someone weighing 200 pounds, that means losing 10 to 20 pounds. For people who are obese and prediabetic, a target closer to 7% to 10% is recommended to meaningfully delay or prevent the transition to diabetes. This weight loss doesn’t need to happen quickly. Steady, sustained loss over several months produces the metabolic shifts that improve how your body handles sugar.
Reshaping Your Plate
The American Diabetes Association recommends filling about 25% of your plate with healthy carbohydrates like brown rice, quinoa, or farro, with the rest devoted to protein and non-starchy vegetables. This isn’t a no-carb approach. It’s about choosing carbohydrates that break down slowly rather than flooding your bloodstream with sugar all at once.
Fiber is a key part of the strategy. Aim for 25 to 30 grams per day from fruits, vegetables, and whole grains. Fiber slows digestion and blunts the blood sugar spikes that happen after meals. Most people eat roughly half that amount, so getting there usually means deliberately adding a serving of vegetables at every meal, switching to whole grains, and snacking on things like berries or nuts instead of processed foods.
Exercise That Improves Insulin Sensitivity
Physical activity directly improves how well your cells respond to insulin, independent of weight loss. The threshold that consistently shows results in studies is moderate-intensity exercise for at least 30 minutes, three to five days per week, sustained for eight weeks or more. Walking briskly, cycling, or swimming all qualify. Some research suggests that higher intensity exercise produces greater improvements than lighter efforts, though any consistent movement helps.
Resistance training, such as lifting weights or bodyweight exercises, also improves glucose control. A typical effective program involves three sessions per week with 8 to 10 exercises covering major muscle groups. The combination of aerobic and resistance training is more effective than either alone.
For people who are short on time, high-intensity interval training offers a compelling alternative. Short bursts of intense effort, like 10 rounds of 60-second sprints with rest in between, have been shown to increase the amount of glucose-transporting protein in muscle cells by up to 260% and improve insulin sensitivity by 25% to 35%. These improvements are comparable to, and sometimes better than, those achieved with longer moderate-intensity sessions.
Sleep and Stress Aren’t Optional
Restricting sleep to four or five hours a night substantially impairs glucose tolerance and insulin sensitivity, even in otherwise healthy people. Sleep deprivation raises evening cortisol levels and triggers the same stress hormones that push blood sugar upward. This means you can be doing everything right with diet and exercise, and poor sleep can still undermine your progress. Seven to eight hours of sleep per night supports the hormonal environment your body needs to process sugar efficiently.
When Medication Enters the Picture
Metformin is the most commonly prescribed medication for people whose glucose intolerance hasn’t responded adequately to lifestyle changes alone. It works by reducing the amount of sugar your liver releases into the bloodstream and by making your cells more responsive to insulin. The typical starting dose is 500 mg twice daily with meals, though clinically meaningful effects generally require at least 1,500 mg per day. Your doctor will check kidney function before prescribing it, since it isn’t appropriate for people with significantly reduced kidney filtration.
A newer class of injectable medications, originally developed for type 2 diabetes and weight loss, is showing strong results for prediabetes. A meta-analysis of nine trials found that people with prediabetes taking these medications were 76% more likely to return to normal blood sugar levels compared to those on placebo. The same analysis found an 83% reduction in the risk of progressing to diabetes. These medications also produced an average weight loss of about 25 pounds over 68 weeks, which itself contributes to improved glucose control. These drugs are not yet standard first-line treatment for prediabetes, but the evidence is building rapidly.
Supplements Worth Knowing About
Berberine, a compound found in several plants, has shown genuine glucose-lowering effects in clinical trials. A 2024 randomized trial published in JAMA Network Open found that a berberine-based compound taken twice daily reduced A1c by 0.4% at the lower dose and 0.7% at the higher dose over 12 weeks, compared to placebo. For context, that higher-dose reduction is in the same ballpark as what metformin achieves. Berberine is available as a supplement, though quality and dosing vary between products, and it can interact with other medications.
Tracking Your Progress
Continuous glucose monitors, small sensors worn on the skin that track blood sugar in real time, are increasingly used by people with prediabetes even though they were originally designed for diabetes management. There are no formal consensus guidelines yet for their use in prediabetes, but early studies show that people who wear them report making better dietary choices, losing more weight, and reducing their A1c. The real-time feedback loop, seeing your blood sugar spike after a particular meal, is a powerful motivator that blood tests every few months simply can’t replicate.
Researchers have proposed that people with prediabetes should aim to keep their blood sugar between 54 and 140 mg/dL for more than 95% of the day. Rather than focusing on average glucose, which can mask the postmeal spikes that are a hallmark of early insulin problems, tracking how often and how high those spikes go may be a more useful measure of progress.
How Quickly You Can Expect Results
One community-based study found that just eight weeks of low-intensity lifestyle changes, modest dietary adjustments and increased physical activity, produced significant reductions in fasting blood sugar and insulin resistance in people with metabolic syndrome. This is encouraging because it means you don’t need to commit to a grueling six-month program before seeing evidence that your efforts are working. That said, longer interventions of three to six months produce more durable and pronounced results, and the goal is sustained change rather than a short-term fix.
A practical timeline: start with dietary changes and exercise, recheck your A1c or fasting glucose in three months, and adjust from there. If your numbers have improved, you’re on the right track. If they haven’t budged despite genuine effort, that’s when a conversation about metformin or other medical options becomes worthwhile.