Monitoring your diet

A healthy, balanced diet is integral to the holistic management of your diabetes. Diabetes doesn’t mean you can’t eat; it simply means to eat right. 

Of all the things that make blood glucose levels rise, food plays the biggest role. Some foods can raise your blood glucose more than others and portion size plays a significant role too. The same foods can have different effects on blood glucose in different people. It’s important to learn what your individual response is and have some control of your diet.

Although it’s helpful to have an individualised eating plan to help with your diabetes, there are basic concepts that are common to everyone. All food can raise blood glucose, but the different macronutrients have different effects. 

1. Carbohydrates, which includes all sugars and starches, raise blood glucose the fastest. For this reason, this is the food group you should have most knowledge about. 

The glycaemic index is a measure of how much a particular carbohydrate is likely to increase the blood glucose by. High-GI foods (white flour, refined cereals, etc.) cause immediate spikes in blood glucose. Low-GI foods slowly increase blood glucose and avoid spikes. Portion plays an important role as higher portions will usually cause higher levels of blood glucose after meals. Hence why you should know the carbohydrate content in various foods to make the right choices. Discuss with your dietitian the right amount of carbohydrates to keep track of the amount eaten and set a limit. 

2. Protein, animal or plant-based, has a minimal effect on blood glucose as long as there is sufficient insulin working in the body. Protein helps a person to feel full which can decrease snacking.

3. Fat has little direct effect onblood glucose, but excess amounts contribute to weight gain and insulin resistance which in turn worsens diabetes control.

A balanced diet must be planned to support a healthy weight and get blood glucose levels to target. These levels can change throughout the day and are affected not only by food but also activity and medication. Measuring your blood glucose levels before and after your meals helps see the immediate effect of your food choices and portions on your blood glucose. This post-meal measurement must be done at two hours after. Glucose levels peak from 1 ½ to two hours after a meal. International and national guidelines have standardised post-meal targets at two hours. 

Self-monitoring of blood glucose chart

A chart to document self-monitoring of blood glucose, also referred to as a diabetes diary, is an important tool in diabetes management. It helps you and your doctor assess the effect of medication as well as to evaluate your meal choices.

For example, if your two-hour post-meal glucose is more than 3mmol/L higher than your before-meal glucose, next time you could eat a smaller portion of carbohydrates.  

You can use apps to measure and monitor dietary intake or speak to your dietitian or diabetes educator for a list of carbohydrates in common foods and use food labels to calculate and record your carbohydrate intake so that you can identify how many carbohydrates are ideal for you.


HbA1c Fasting blood glucose mmol/L Two-hour post meal blood glucose mmol/L
YOUNG < 6,5% 4 – 7 4,4 – 7,8
MOST < 7,0% 4 – 7 5 – 10
ELDERLY < 7,5% 4 – 7 < 12
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