Food & drink

Food - how it affects glucose in your blood

To understand how eating affects your levels you need to know a little about how glucose arrives in and leaves your blood.

Where the glucose in your blood comes from

There are two main sources of glucose in your blood:

• Digesting the carbohydrates you eat
  Carbohydrate foods are sugars and starches such as sweets or potatoes. Carbohydrates from the food you eat are the main source of glucose in your blood. In your gut you break down carbohydrates into sugars, mainly glucose, and absorb them into your blood
• Producing glucose inside your body
  Your body can also produce glucose internally from a special store in the liver, called glycogen. Glycogen is your body's emergency glucose store. If your blood glucose falls too low your liver immediately starts breaking down your glycogen stores to make glucose. (Unfortunately you are unlikely to have glycogen stores big enough to prevent a hypo)

Where the glucose goes

Glucose is your body's main fuel. Your muscles and brain need it, just like a car needs petrol. Your blood carries glucose around your body to where it is needed. To get the glucose out of your blood and into your tissues you need insulin. Insulin either moves the glucose from your blood into your muscles and brain for energy or stores it in your liver (as glycogen) or under your skin and around internal organs (as fat). When you treat your diabetes with insulin you try to match the action of the insulin you inject with the food you eat.
 

Why your weight makes a difference

We hear a lot nowadays about the health benefits of avoiding being overweight, but if you have diabetes there is one extra advantage of keeping off the fat.

In your body, insulin seems to find moving glucose out of your blood into fatty tissue particularly difficult; so the more weight you carry, the more insulin you may need to inject.

Of course the opposite is true too; if you lose weight you should need less insulin. That is why blood glucose testing is so important when you are on a diet.