Managing prediabetes

Food and prediabetes

• A reduction in ultra-processed ("junk") foods and sugary foods is helpful for improving prediabetes.
• A reduction in carbohydrate (starchy) foods has the most evidence for improving prediabetes, and can fit with all other dietary preferences.
• People respond differently to foods, so choices should be adapted to what works.
• An appropriate diet will lead to improvement in prediabetes and overall health.

My patients are often confused about whether bread, breakfast cereals, and fruit juice are healthy choices or not. The labelling and marketing of these foods and drinks can often give an impression of health. However, because all these foods become sugar when digested they can lead to a significant rise in blood glucose and this can potentially worsen prediabetes.

Start somewhere, see what happens, and adjust if needed.

There are some common features of all diets that help prediabetes. These are:

Minimise or avoid

• Ultra-processed foods. This includes foods that are commonly called "junk food". It also includes other packeted or boxed foods that may even be labelled as being healthy. As a general rule, if it comes in a packet or box and has four or more ingredients then it is probably an ultra-processed food.
• Sugary drinks. This includes sugary soft drinks, fruit juices, and sugar to hot drinks.
• Sugary foods. This includes sweets, cakes, biscuits, jams, honey, and dried fruit.

Enjoy

• Eating "real" foods. This means foods that have not been changed in a factory. They would have been recognised as food by our ancestors.
• Adequate protein. The body needs a certain amount of protein from food and it reduces hunger.
• Non-starchy vegetables. This includes most vegetables that grow above the ground.

Reduce

• Starchy carbohydrate. This means foods such as bread, rice, potatoes, pasta, and breakfast cereals. Starchy carbohydrates are digested into sugar in the gut and raise the blood sugar level. People differ in how much carbohydrate their body can manage, so the amount should be lowered to a level that works for the individual.

Specific dietary approaches can make choices easier. Some people like to follow strict dietary rules, whereas other people prefer more relaxed options. It is also common for people to frequently change their dietary approach. The "right" diet will improve prediabetes and overall health.

Typically, the lower the amount of carbohydrate the greater the improvement in blood sugar.

Each diet below has a traffic-light download to help with food choices.

A high protein diet focuses on eating foods with plenty of protein and less carbohydrate and fat. The higher protein amount will often lead to a person being less hungry and needing to eat less food. A high protein diet is often helpful for people that wish to improve prediabetes and lose body fat.

• Download the High Protein Diet Food Lists

A very low carbohydrate diet is also known as a ketogenic or "keto" diet. This means no more than about 50g of carbohydrate a day. It involves completely cutting out all sugary and starchy foods. The amount of fat eaten is usually increased. Some people are able to eat more fat and get good health improvement, whereas other people need to be careful not to eat too much fat.

• Download the Very Low Carbohydrate Diet Food Lists

A low carbohydrate diet means some starchy foods can still be eaten, but only in smaller amounts. Sugary foods are minimised. A low carbohydrate diet has under 130g of carbohydrate per day.

• Download the Low Carbohydrate Diet Food Lists

A moderate carbohydrate diet allows for more starchy foods, but typically this is less than what someone would have previously eaten. The amount carbohydrate eaten will be around 130-180g per day. A moderate carbohydrate diet still requires that ultra-processed food and sugar are minimised. For some people a moderate carbohydrate diet is sufficient to improve prediabetes, but this will not work for everyone. If improvement of prediabetes is not achieved then moving to a lower carbohydrate diet may be helpful.

• Download the Moderate Carbohydrate Diet Food Lists

• Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base
• Evert AB, Dennison M, Gardner CD, et al. Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care.