Myth or fact

Do you have to cut carbs to reverse prediabetes?

Short answerNo

By GyroscopeUpdated November 14, 20268 sources

No. The trial that cut new diabetes by 58% used a low-fat diet, and what predicted success was weight lost, not carbs cut. The ADA’s 2026 standards say there’s no ideal share of carbs, protein and fat for preventing diabetes. Low carb is one good option among several, so pick the pattern you’ll still be eating in a year.

Why do people think they have to cut carbs?

The logic is tidy. Carbs turn into blood sugar, prediabetes is high blood sugar, so stop eating carbs. A sensor seems to prove it within a day, since skipping the bread makes the hill disappear. Low-carb and keto communities are full of people who say their A1c dropped, and many of them are telling the truth.

The catch is the difference between today’s hill and your risk. Cutting carbs makes today’s after-meal number smaller, the same way skipping a meal would. Prediabetes is about how well your body handles carbs, and that’s set mostly by your weight, your muscles and how much you move.

What did the trial that worked actually use?

The Diabetes Prevention Program put 3,234 American adults with raised blood sugar on a lifestyle program, metformin or a placebo. The lifestyle group’s goals were at least 7% weight loss on a healthy low-calorie, low-fat diet, and at least 150 minutes a week of activity such as brisk walking. Over 2.8 years they had 58% fewer new cases of diabetes than the placebo group.

When researchers later looked at what predicted success in 1,079 people from the lifestyle group, weight loss came first. Each kilogram lost (2.2 pounds) went with 16% lower diabetes risk, even after adjusting for changes in diet and activity. The diet mattered because it helped people lose weight.

Is low carb better for losing weight?

In a year of real life, no. In the DIETFITS trial at Stanford, 609 adults were put on a healthy low-fat or a healthy low-carb diet for 12 months. The low-fat group lost about 5.3 kg (12 pounds) and the low-carb group about 6.0 kg (13 pounds), a gap too small to be sure of. The researchers also measured how much insulin each person made after sugar, expecting the high-insulin people to do better on low carb. They didn’t.

Both work, and the one that works for you is the one you can stick with. bodyfat.guide takes apart the idea that carbs make you store fat through insulin, in does insulin from carbs make you store fat.

What does the ADA say?

The ADA’s 2026 standards for preventing diabetes ask for at least 5 to 7% weight loss and 150 minutes a week of activity, and an evidence-based eating pattern. They name Mediterranean and low-carbohydrate eating as examples, and say “there is no ideal percentage of calories from carbohydrate, protein, and fat” to prevent diabetes.

Which carbs should go first?

Start with the ones with the clearest links and the least upside.

Sugary drinks. Each daily serving went with 13% more type 2 diabetes, even after adjusting for bodyfat.

Refined, finely milled starch. White bread scores 75 on the glycemic index, instant oats 79, cornflakes 81 and rice crackers 87. Rolled oats score 55, white spaghetti 49 and lentils 32.

Juice, not fruit. Whole blueberries, grapes and apples went with less type 2 diabetes in a study of 187,382 people. Juice went with more.

Keep the beans, the whole fruit and the grains you can still see. They’re carbs too, and whole fruit went with less diabetes, not more.

The best case for cutting carbs

Low carb is a fine tool if it’s the one you’ll keep. It isn’t the only door, and nobody should feel they’ve failed prediabetes because they still eat rice.

Is there a middle way?

Eat the carbs last. In a 2019 trial, 15 adults with prediabetes ate the same meal three ways. When they ate the protein and vegetables first and the carbs 10 minutes later, the peak was about 46% lower than when they ate the carbs first. Nothing was cut. Add a 10-minute walk after dinner and you’ve shrunk the biggest hill of the day without giving up anything. Then put the real effort into the plan.