Managing diabetes: what foods to eat and avoid

Type 2 diabetes is primarily caused by being overweight. Excess body fat means your body is more resistant to insulin, a phenomenon known as insulin resistance.

This means insulin is unable to manage your blood glucose levels, which can result in developing type 2 diabetes if left untreated.

To manage type 2 diabetes, this means you need to change your diet to help you lose weight and keep your blood sugar levels stable.

Treating your diabetes will help prevent other health problems like foot problems, eye problems and heart disease.

If you have diabetes, one of the most important food groups you have to consider is sugars.

The glycaemic index (GI) is an indicator of whether a certain food will raise your blood sugar levels quickly, moderately or slowly. It’s a score of 0 - 100. Pure sugar, for example, is at 95. Low GI foods are scored 55 or lower.

GI is an important factor for your diet if you have diabetes. High GI carbs will spike your blood sugar levels, and will cause overall higher blood sugar levels over time. Medium GI foods and high GI foods are okay in moderation

Eating with diabetes is a balance of eating healthy and thinking about your blood sugar. Here are some of the main foods you should prioritise when meal planning.

Low GI carbs

Carbohydrates are an important part of a healthy diet. However, with diabetes, you’re more susceptible to blood sugar spikes. So, you need to choose your carbohydrates carefully.

Low or medium GI carbs will not spike your blood sugar levels suddenly nor as high as high GI carbs, which means they’re a safe and healthier choice for diabetics.

Low-GI carbs include:

• most fruit and vegetables
• beans and pulses
• minimally-processed grains
• wholegrain foods (porridge oats, brown rice or sourdough bread)

One exception is chocolate. Some types of chocolate may have a low GI but are still unhealthy, as they are added sugars.

Medium GI foods are okay every once in a while. However, you should try and switch out a medium GI carb for a low GI carb. Some medium GI carbs include:

• wholemeal bread
• cous cous
• long grain or jasmine rice

Consider what carbohydrates you have at home and how you can adapt your meals to have a lower GI.

Fruit and vegetables

A common misconception is that people shouldn’t eat fruit if they have diabetes because it’s too sugary. But, the sugars in fruit are different from those in processed foods.

Fruits contain total sugars. These occur naturally in the fruit. However, most unhealthy foods contain added sugars called free sugars. Because of the way they are manufactured, they lose all of their natural benefits and are high in calories.

Free sugars include most sweet snacks but also fruit juices, honey and maple syrup.

You should try and include fruit and vegetables in every meal. They have a lot of additional nutrients such as fibre and are a natural source of energy.

Some good fruit and vegetable choices include:

How you prepare your fruit and vegetables will also change the GI value. For example, cooked carrots have a high GI value (85).

Some medium and high GI fruits and vegetables include:

• dates (70)
• cooked plantain (70)
• cooked turnip (85)
• watermelon (75)
• pineapple (66)
• raisins (65)
• pumpkin (65)
• mango (56)

This is not an exhaustive list. However, fruits and vegetables that have a GI of less than 55 will not spike your blood sugar and are a healthier choice for diabetics.

Lean protein

Another important component of a healthy diet is lean protein. These are sources of protein that are low in fat such as:

• fish
• chicken
• turkey
• eggs
• soy
• legumes and beans

Protein is also good for weight loss. It fills you up more than food groups. So if you eat a high-protein meal, you are less likely to feel hungry afterwards.

They also may lower the overall GI of your meals, even if you have a high GI carbohydrate in your meal. So, it’s a good idea to always add protein to your meals.

Healthy fats

The final food group you should prioritise is healthy fats. In nutrition, these are known as unsaturated fats.

They are better for your heart health as they do not increase your cholesterol levels. High cholesterol is a risk factor for heart disease and is a common complication in those with type 2 diabetes.

Foods that are a good source of healthy fats are:

• oily fish (e.g. salmon or mackerel)
• certain oils from vegetables, nuts or seeds (e.g. sunflower oil, rapeseed oil, olive oil or peanut oil)
• avocado
• nuts and seeds
• oil-based spreads

You should cut out saturated fats which are common in many processed foods, fatty meats and full-fat dairy products. Some products you cook with are also high in saturated fats like lard, ghee and coconut oil.

You shouldn’t focus so much on the foods you should cut out because it can make a lifestyle change much harder.

However, you should eat some foods in moderation, such as:

• High-fat foods (e.g. pizzas, burgers and crisps) - they are high in calories with little nutritional value. They also can increase your risk of high cholesterol.
• Certain high GI carbs (e.g. cakes, biscuits, white bread, white rice and breakfast cereals) - will spike your blood sugar levels and are high in calories.
• Foods high in salt (e.g. ready meals and deli meats) - not only are they high in calories, but they can increase the risk of high blood pressure.
• Foods listed as “diabetic foods” (e.g. diabetic jams) - there is no evidence that these foods are good for diabetes.
• Alcohol – some alcohols will have a high GI (e.g. beer). However, most alcoholic drinks will be high in calories regardless of their GI such as wine, cider and cocktails.

In general, you should also eat mindfully to lose weight. Some people may find counting calories, planning their meals or weighing out their food helpful to stay on track.

You should ask your doctor for more advice if you need more advice on weight loss.

Unlike type 2 diabetes, type 1 diabetes is not caused by dietary choices. People with type 1 diabetes cannot produce insulin because their immune systems attack the insulin-producing cells. So, they have to take insulin.

While you don’t have to completely change your diet, you will need to consider how many carbohydrates you eat. This is known as carb counting. The amount will depend on your age, activity levels, weight and the type of insulin you use.

If you use a twice-daily insulin, you may find it beneficial to eat a consistent amount of carbohydrates at similar times each day. This will help keep your blood sugar levels stable.

If you use a basal-bolus insulin regime, you can be more flexible in how much carbs you eat and when you eat. You will need to calculate the carbs you need to eat or drink and then how much insulin you will need to take.

Your diabetes healthcare team will help you work out your insulin-to-carbohydrates ratios.

You should still opt for low-GI carbohydrates where possible, as they can help with overall blood sugar levels. They will also help you with weight management if you are looking to lose weight.

Hypoglycaemia or “hypo” is what happens when your blood sugar levels drop very low. This causes symptoms such as:

• feeling shaky
• feeling disorientated and unable to concentrate
• sweating and night sweats
• palpitations and a fast pulse
• going pale
• blurred vision
• feeling tearful, anxious or irritable
• tiredness
• headache

It is especially common in people who need to take insulin.

If you experience any symptoms, check your blood sugar. If it’s low (below 4mmol/l), you need to treat it immediately. To treat it, you need to eat or drink 15-20g of a fast-acting carbohydrate (high GI). This could be:

• five glucose or dextrose tablets
• a small glass of a sugary drink or fruit juice (150 - 200ml)
• two tubes of a glucose gel (e.g. GlucoGel)

You should check your blood sugar 10-15 minutes after to ensure it’s at a healthy level. After treating a hypo, you should have a slow-acting carbohydrate (low GI) like a piece of toast or fruit. You could also have your next meal if it’s due.

If you have diabetes, you may need to alter your diet.

You will need to watch what types of carbohydrates you eat, even if you take insulin. This is because of a lack of insulin or insulin that doesn’t work properly, your blood sugar levels can spike more easily.

You should also make healthier food choices. This is especially true if you have type 2 diabetes as weight loss will help improve your condition and reduce your risk of health problems.