How to snack when you have diabetes

At mealtimes, we can't always plan exactly how much food we need until the next meal. And if you have diabetes, it can be even trickier. But the aim of good diabetic control is to keep your sugar levels steady, so the ideal snack will satisfy your hunger, but be low in fat and sugar.

Fruit, biscuits, or cereal bars are useful, portable snacks. Always carry glucose tablets or gel or a non-diet soft drink too, to prevent low blood sugar (hypoglycaemia).

Snacking with type 1 diabetes

If you have type 1 diabetes, you may need to eat carbohydrate snacks during the day to help balance your blood sugar levels.

Hunger

Like anyone, if you have type 1 diabetes you might get hungry between meals. Low blood sugar is not the only cause of hunger, although it can trigger it.

If you take insulin twice a day then you are fairly likely to need to snack between meals to prevent a hypo. But if you take insulin with each meal then you won't usually need to snack. Your dietitian will be able to advise you.

Exercise

You might need to snack before or after physical activity - sometimes both. If you are on insulin and you are about to be very active, then it is usually best to snack before you start, particularly if your blood glucose is already low in your range.

When snacks cause problems

It's easy to accidentally overcompensate if you have type 1 diabetes. Take three-year-old Mia* who has this condition. Her mum, Jenny, also has type 1 diabetes, and a history of having hypos at night, which frightened her.

Whenever Mia came to the diabetes clinic, her blood tests suggested that her control was very poor. The dietitian spent some time with Mia and her mum and discovered that Mia's chosen snack was a mini Mars bar. Because her Mum worried about night-time hypos, Mia always had one or two of these beside her bed. She liked them so much that she would eat them each night, and would often request extra during the day.

But even a small Mars bar is a big snack for a little girl, and not something she needed during the night if she wasn't having hypos. Mia wasn't very pleased at first but with reward and praise she was weaned off her late-night snacks and her control improved dramatically.

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Snacking with type 2 diabetes

People with type 2 diabetes are resistant to insulin, rather than not being able to produce it. Those who are not on any medication will not develop low blood sugar, so won't need to snack in the way that people with type 1 diabetes do.

If you take insulin or diabetes medicines that lower your blood glucose - particularly sulfonylurea tablets, which carry a much higher likelihood of hypos than other tablets - you may need a snack between meals in order to keep your blood sugar in the normal range.

Can your body mislead you?

Roy* is in his seventies, has type 2 diabetes and has always liked a plain digestive biscuit with his tea. He'd been on insulin for some years but had gradually put on weight, so needed a steadily increasing dose. Unfortunately, after a fall, he broke his foot and had to come into hospital as it wasn't healing.

It became obvious when Roy was on the ward that he was now eating half a packet of digestives every time he felt hypo, and this was happening two or three times a day. He insisted that it took this amount of biscuits to make the hypo feeling go away. He had tried fewer but it just didn't work.

The specialist diabetes nurse spent some time with Roy. For a couple of days she watched as he did things his way, but tested his blood sugars before and after the biscuits - when he felt hypo, and when he felt better. She was able to show him that his blood sugar was 12 when he felt low, and 17-18 when he felt better. Roy was having false hypo sensations because he was so accustomed to running high. It took some time for Roy to adjust back, but gradually his control improved, and he gave up digestive biscuits completely.

What should I snack on?

The key to snacking with diabetes is to choose snacks that are high in fibre, protein and healthy fats.

Snacks to eat

Snacks to avoid

Generally speaking, if you have type 1 or type 2 diabetes, you should avoid high-fat, high-salt foods, such as:

All carbohydrates increase your blood sugar. These include sugary carbs - found in sweets, sugary drinks, cakes and desserts, as well as in fruit - and starchy carbs - found in pasta, bread, cereals and starchy vegetables like potatoes. However, low glycaemic index (GI) carbs are absorbed more slowly into your system and release energy more slowly too, so they reduce sharp rises in blood sugar.

Wholegrain and high-fibre foods have a lower GI than refined versions. Whole fruit contains carbs, but they're mixed in with fibre and broken down more slowly than standard sugar. That's why tinned fruit in syrup or fruit juice causes your blood sugar to rise faster than whole fruit.

But it's more complicated than that. For instance, wholemeal bread - where the whole grain is in the bread but has been ground up - is relatively high GI. The fat content of food affects its GI as well - so chocolate is medium GI despite all the sugar it contains. Protein also lowers GI, so milk and dairy products, which contain protein and fat, are low GI.

It's also important to remember that some low-carb foods are high in calories, and that a huge portion of low GI food will raise your blood sugar more than a small portion of the same food.

And you don't need special 'diabetic' snacks.

Diabetes UK advises against buying snacks marketed as 'diabetic'. These products are generally overpriced, with no unique health advantages. Try incorporating your preferred snacks into your daily diet, but be mindful of how much you eat.

Remember, if something tastes very sweet it may be high in sugar, and if something is deep-fried it is almost certainly high in fat.

How to make snacks more interesting

If you can keep a broad range of snack ingredients in your fridge and food cupboard, then you should be able to create healthy snacks that appeal to you out of your weekly shop.

*Names have been changed to protect identities.

Dr Mary Lowth is an author or the original author of this leaflet.