Ask a Dietitian

We’re excited to have launched a brand-new section in Membership Matters: Ask a Dietitian!

Each month, we’re answering a common nutrition question from our community. This month, we’re exploring a popular one: “Since being put on insulin 6 months ago, I have put on a lot of weight. Is it normal for this to happen when using insulin? I am a type 2 diabetic.”
 

Since being put on insulin 6 months ago, I have put on a lot of weight. Is it normal for this to happen when using insulin? I am a type 2 diabetic

There may be two possible reasons for this:

You may be having too much insulin, resulting in you having to eat to keep your blood glucose levels from going too low
Some people lose weight (without trying) before starting insulin (less common in type 2 diabetes). This happens because blood glucose levels have been too high, and the body is removing glucose through the kidneys in urine, leading to weight loss. Starting insulin may reverse this weight loss, hence appearing to gain weight.

Let’s first look at how insulin production changes over time in type 2 diabetes. Over time, the insulin-producing cells (called beta cells) in the pancreas can’t keep up with the body’s needs, so people produce less of their own insulin. Starting insulin injections to manage type 2 diabetes is a common and often necessary part of treatment. This insulin tops up the body’s own insulin supply and helps the body absorb glucose again, a form of energy or fuel for the body.

It is common to gain around 2kg in the first year of starting insulin, before stabilising.

As a growth hormone, insulin works in three ways:

Insulin helps glucose in the blood enter muscles and other cells so you can use it for energy
Once your cells have enough glucose, insulin helps store excess glucose as glycogen in the liver and in muscle cells
When your liver stores are full, the remaining glucose converts to fat as a secondary energy source.

So, if you eat more carbohydrate than you use up, you will store the excess glucose first as glycogen, and then as fat. This can result in weight gain.

Having too much insulin can lower your blood glucose levels too much. This can cause a “hypo”, or hypoglycaemia, which is where blood glucose levels are too low (glucose levels under 4mmol/L). You would then need to treat the hypo by having more carbohydrate, e.g., 6-7 jelly beans, 150mL sugary drink to rapidly increase your blood glucose level. Do re-check your blood glucose again after 15 minutes to make sure the level is back in your target range. If you need carbohydrate to treat hypos, it means that you are eating or drinking more energy (kilojoules) than you were before.

If you have frequent hypos, or if you find that you “need to eat” to keep your blood glucose levels steady, then you may be taking too much insulin. The best way to safely reduce your insulin dose is to ask for help from your doctor or diabetes nurse educator

Author: Ivan Chan (Accredited Practising Dietitian at Diabetes Victoria)

Have your say

If there is a topic/question you’d like us to cover in a future edition, please click the link below – we’d love to hear from you!

Submit your question

Previous questions

If I have diabetes, should I have apple cider vinegar every day?

Answer – There is no strong evidence to recommend having apple cider vinegar every day for people with or without diabetes.

However, you may notice a small reduction in your blood glucose levels when adding an acidic ingredient to a meal that contains carbohydrate.

Acidic ingredients like apple cider vinegar slow down digestion and lower the glycaemic index (GI) of a meal. This means that glucose from your food enters the bloodstream more slowly, which can help flatten the rise in blood glucose levels after a meal.

It’s important to know that this effect isn’t specific to apple cider vinegar. Other acidic foods, like white vinegar, balsamic vinegar, or lemon juice have a similar effect. The key factor is the acid content, not the specific type of vinegar.

Practical tips for using acidity to help with blood glucose:

Add vinegar or lemon juice to meals. Drizzle on salads, cooked vegetables, or starchy foods like rice or potatoes.
Dilute it: Straight vinegar can irritate your teeth, throat, and stomach. Mix 1-2 teaspoons of vinegar in water and consume before a meal.
Combine with carbohydrate-containing meals. The GI lowering effect is most noticeable with foods high in starch like rice or potatoes.
Be consistent and observe your response. Check your blood glucose before and 2 hours after meals to see how you respond. Compare this to the same meal without the acidic ingredient.

The effect is usually small and varies between people. Consider these tips as a small addition to an overall balanced eating plan.

Author: Charlotte Lentfer – Dietitian and credentialed diabetes educator

Do diet drinks make your blood glucose levels go up?

Short answer: No.

Diet drinks do not make your blood glucose levels go up. Diet drinks contain artificial sweeteners instead of sugar. Artificial sweeteners have very few kilojoules (or calories) and no carbohydrates. Switching from a regular soft drink to a diet alternative can help keep blood glucose levels more stable and support weight management.

Can we drink as much as we want?

Not really. The World Health Organisation recommends reducing the overall sweetness of our diets. This includes the sweetness that comes from artificial sweeteners.

Fun fact: Artificial sweeteners actually taste much sweeter than sugar. This can increase a person’s preference for sweet flavours.

Diet drinks contain no nutritional value or health benefits. When people drink large amounts, they are likely replacing food or drinks that provide key nutrients like protein, fibre, vitamins, and minerals. So, if you do choose diet drinks, it’s best to have them in moderation and as part of a balanced diet.

Looking for more information?

Make an appointment with one of our dietitians who works at the Diabetes Care+ clinic.

Author: Sammie Lyne, Accredited Practising Dietitian, Diabetes Victoria

Can I still eat fruit if I have diabetes?

Response composed by dietetic students Kate Hadkens and Emma Westlake (December 2025)

The short answer is yes! Fruit is a nutritional powerhouse and eating fruit regularly has been shown to actually reduce the risk of developing type 2 diabetes and prevent related complications such as heart disease, kidney disease, and stroke.

While fruit does contain the natural sugar fructose, most fruits have a low glycaemic index (GI) due to the fact they also contain fibre. This means that the natural sugar in fruit is digested slowly, preventing rapid rises in glucose levels. Fruit is also an excellent source of vitamins and minerals that help keep our immune system healthy and supports good gut health.

Whether you have diabetes or not, it is still recommended that you eat two servings of fruit each day. One serve of fruit is about the size of a closed-fist, such as one medium apple, banana or pear OR two small apricots, kiwifruits or plums.  It is best to eat fresh fruit over those stored in syrups or fruit juices.

Be mindful that fruit juice (whether made with or without added sugar) will result in rapid rises in glucose levels as it is in liquid form, contains a larger volume of fruit in one-go and less fibre than eating fruit in its whole form.

Do you have a question for our dietitians for our next edition of membership matters? If so, you can submit it by clicking here or by clicking the ‘Submit your question’ button above.

Alternatively, if you would like an appointment with one of our diabetes specialist dietitians for individualised advice, you can call our Diabetes CarePlus clinic on 1300 153 123.

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