Diet for Prediabetes: What to Eat to Lower Blood Sugar

01What

What is prediabetes?

Prediabetes is diagnosed when fasting glucose is 100–125 mg/dL (5.6–6.9 mmol/L), HbA1c is 5.7–6.4% (39–47 mmol/mol) or glucose two hours after a glucose load is 140–199 mg/dL. It usually reflects insulin resistance linked to excess weight, particularly abdominal fat, inactivity, family history and age. It has no symptoms, which is why many people are unaware. Without changes, about 5–10% a year progress to type 2 diabetes, and it is also linked with higher cardiovascular risk.

02Goals

The goals of diet and lifestyle

• Lose 5–7% of body weight if overweight (for example 5–7 kg for a person weighing 100 kg).
• Be active: 150 minutes of moderate activity weekly, plus strength training twice a week.
• Improve food quality: more fibre and whole foods, fewer refined carbs and sugary drinks.
• Sleep well, manage stress and avoid smoking.
• Monitor: repeat HbA1c or glucose tests at least yearly, or as advised.
• See balanced diet for weight loss.

03Plate

The plate method

• Half the plate: non-starchy vegetables (leafy greens, broccoli, peppers, tomatoes, courgette).
• A quarter: lean protein (fish, poultry, eggs, tofu, legumes).
• A quarter: carbohydrate-rich foods that are high in fibre (whole grains, beans, sweet potato, quinoa).
• Add: a small amount of healthy fat (olive oil, nuts, avocado).
• Drink: water, unsweetened tea or coffee.
• The plate method works without counting carbohydrates and is endorsed by diabetes organisations.

04Eat

Foods to prioritise

• Vegetables, especially non-starchy and leafy.
• Legumes: beans, lentils and chickpeas, high in fibre and protein with a gentle effect on glucose.
• Whole grains: oats, barley, brown rice, whole-wheat bread and pasta, in controlled portions.
• Fruit in whole form (berries, apples, pears, citrus).
• Nuts and seeds in small portions.
• Fish, poultry, eggs and low-fat dairy.
• Healthy fats: olive oil, avocado, fatty fish.
• Vinegar and cinnamon may have small effects, but are not substitutes for diet.

05Limit

Foods to limit

• Sugary drinks, fruit juice and energy drinks.
• White bread, white rice, refined cereals and pastries.
• Sweets, biscuits, cakes and desserts.
• Ultra-processed snacks and ready meals.
• Processed and red meat in large amounts.
• Fried foods and trans fats.
• Alcohol in excess.
• Large portions, particularly of starchy foods.

06Carbs

Carbohydrate quality and timing

Total carbohydrate amount, quality and what you eat them with all influence blood sugar. Choose high-fibre, minimally processed carbohydrates, which are digested slowly (lower glycaemic index and load). Combining carbohydrates with protein, fat or vegetables flattens the glucose rise. Eat regular meals and avoid very large carbohydrate loads in one sitting. A short walk after meals lowers post-meal glucose. Low-carbohydrate and Mediterranean patterns can both be effective if followed consistently.

07Menu

Sample day

• Breakfast: plain Greek yoghurt with berries, walnuts and a sprinkling of oats; or a vegetable omelette with a slice of whole-grain toast.
• Lunch: lentil and vegetable soup, a large mixed salad with olive oil and a small piece of whole-grain bread.
• Snack: an apple with a spoon of peanut butter, or hummus with raw vegetables.
• Dinner: grilled fish or chicken, roasted vegetables and a small portion of quinoa or sweet potato.
• Drink water; avoid sugary beverages.

08Medicines

Medicines and monitoring

For some people at high risk, doctors may suggest metformin alongside lifestyle changes, particularly with a BMI of 35 or more, age under 60 or previous gestational diabetes. Newer weight-loss medicines may be considered when obesity is present. Regular check-ups assess glucose, blood pressure, cholesterol and weight. Home glucose monitoring is not normally required for prediabetes, unless advised.

10Cases

Three common situations

HbA1c of 6.0% and a BMI of 31: aim for 5–7% weight loss, daily walking, a plate-based diet and a recheck in 3–6 months.

Normal weight but prediabetes and a family history: focus on food quality, activity and sleep, and monitor annually.

Someone who loves sweets: swap sugary drinks for water and sweets for fruit with nuts; keep portions of desserts small.

11Exercise

Exercise that improves insulin sensitivity

Both aerobic activity (brisk walking, cycling, swimming) and resistance training improve how muscles use glucose, and the benefits begin within days. Aim for 150 minutes of moderate aerobic activity a week, spread over at least three days, plus two strength sessions. A 10–15 minute walk after meals reduces post-meal glucose. Break up long sitting periods every 30 minutes. Choose activities you enjoy and build gradually, with medical advice if you have heart disease or other conditions.

12Summary

Key points to remember

Prediabetes is reversible for many. Lose 5–7% of body weight, move regularly, eat plenty of vegetables, legumes and whole foods and limit sugary and refined foods. Get regular check-ups. Our nutrition team can build a plan around your life.

This guide is for general information and does not replace an assessment by your own doctor or dietitian.