I’ve had diabetes for 20 years — how I keep my blood sugar levels stable

I was diagnosed with Type 1 diabetes at the age of nine and have tried a plethora of different treatments to keep my blood glucose levels under control. The chronic autoimmune condition should not be confused with the more common Type 2 diabetes. Unlike Type 2 diabetes, Type 1 is not at all related to weight or insulin resistance and cannot be prevented. Also, unlike Type 2 diabetes, my pancreas does not produce any insulin, which means I cannot regulate my blood glucose without administering my own insulin. I currently inject myself with insulin multiple times a day, but insulin pumps are becoming more widely available on the NHS.

Without insulin, our bodies can’t regulate blood glucose levels, leading to high blood sugar. The autoimmune disorder is usually diagnosed in children or young adults, which is why it was once known as ‘juvenile diabetes’. Over the years, managing the disease has been challenging, with phases of prolonged high blood sugar and some incidents of low blood sugar. However, I’ve come to realise that one regular habit keeps them particularly well-balanced: fasting.

I currently use a sensor-based glucose monitoring system that measures glucose in my interstitial fluid and sends data to my phone every minute. This means I can monitor the effects of certain foods, drinks and activities on my blood glucose levels in real-time.

Fasting for long periods stabilises my blood sugar without me having to inject insulin.

For me, the best time to fast is in the morning. I stop eating at 7pm the night before and won’t eat until around 1pm the next day, which amounts to about 18 hours of fasting. During that time, I drink water and sugar-free squash and will sometimes have a decaffeinated black coffee.

Don’t get me wrong, there are occasions when I eat breakfast. In fact, I recently tried to get into the habit of eating breakfast after I started making my own granola. However, I found my blood sugars would spike quite rapidly, even when I injected the correct amount of insulin. I also found I experienced a mid-morning slump, which made me less productive.

There’s also the odd occasion where I’ll enjoy a cooked breakfast on the weekend, some scrambled eggs on toast or even a cheeky croissant or two when I’m on holiday. But most of the time, I skip breakfast completely.

Sandra Cohen, a consultant nutritionist listed on Doctify, a healthcare review platform, says fasting can be helpful for blood sugar regulation in some people – but stresses it’s highly individual and not appropriate for everyone.

She explains: “Fasting can improve insulin sensitivity by reducing the frequency of glucose spikes and allowing the body to shift from using glucose to burning stored fat for energy. This metabolic switch can support more stable blood sugar levels in some individuals, particularly when fasting is done in a structured and personalised way.”

She explains that intermittent fasting may support metabolic health by improving how cells respond to insulin.

“One of the key benefits of intermittent fasting is improved insulin sensitivity. By giving the body regular breaks from food, fasting can reduce overall insulin demand, which may help stabilise blood glucose levels over time,” she said.

However, Ms Cohen is clear that fasting is not universally beneficial, especially for some people managing diabetes.

She said: “Fasting can increase the risk of hypoglycaemia, particularly for people with diabetes who use insulin or glucose-lowering medication. Even when blood sugars feel more stable subjectively, there can be hidden risks if fasting isn’t medically supervised.”

Hypoglycaemia is when blood glucose levels drop below 4 mmol/L. This commonly affects people with diabetes who use insulin. Some of the symptoms I experience when my blood sugars drop below this level include shaky hands, sweating, hunger, anxiety, dizziness and irritability. It quite literally feels like you’re ‘hangry’.

To treat hypoglycaemia, you usually have to consume fast-acting carbohydrates such as a sugary drink or sweets like jelly babies.

Ms Cohen also highlighted that fasting for long periods of time can backfire. She said: “Extended fasting or insufficient nutrient intake can disrupt hormones, increase cortisol, and lead to blood sugar instability rather than improvement – especially in people under chronic stress or with underlying endocrine conditions.”

Ms Cohen emphasises that context matters when it comes to fasting. She said, “Fasting should be a supportive tool, not a stressor. For some people, shorter fasting windows of 12–14 hours may offer metabolic benefits without increasing the risk of blood sugar crashes.”

She added, “Anyone with diabetes, particularly those on medication, should only experiment with fasting under professional guidance. What supports blood sugar stability for one person may be unsafe for another.”

Ann Jarris, a board‐certified emergency physician and Medical Director at Response Ready, said “fasting can smooth out large post‐meal glucose swings and simplify insulin dosing for some people”.

She continued: “A modest, earlier time‐restricted eating window (for example, finishing dinner early) often reduces late‐night hyperglycaemia, steadies overnight numbers, and trims total bolus needs. Short fasting intervals also give clearer feedback on basal adequacy and, with CGM or automated insulin delivery, can translate into more time‐in‐range with fewer corrections. These benefits show up most when the approach is gentle, consistent, and reviewed with a clinician who can adjust insulin safely.”

Ann Garry, qualified nutritionist, CEO and head of nutrition training at Health Coaches Academy, added: “From a nutritional therapy perspective, periods of reduced eating can, for some people, improve blood glucose stability by reducing the number of glucose and insulin fluctuations across the day. Research in non-diabetic and insulin-resistant populations suggests that intermittent fasting or time-restricted eating may reduce glycaemic variability and post-prandial glucose exposure. However, it’s important to be clear that research specifically examining fasting in people with Type 1 diabetes is currently very limited.”

Erin Viljoen, a nutritional therapist at W-Wellness said research shows that fasting can support blood sugar control in several ways. She added: “It helps to improve insulin sensitivity, meaning the body uses glucose more efficiently and blood sugar levels stay steadier. Studies and scoping reviews have also found that fasting can lower fasting glucose and modestly reduce HbA1c, a key marker of long-term glucose control.

“Interestingly, some benefits appear even without cutting calories. Simply limiting eating to an eight-hour window, for example, from 10am to 6pm, has been shown to improve blood sugar regulation. Starting with fasting does not need to be extreme. Even extending your natural overnight fast by finishing dinner a little earlier and delaying breakfast by an hour or two, can offer benefits.

“People are often concerned that the body will ‘starve’ during fasting. This is not the case. As long as we have fat stores, the body will adapt by switching from glucose as fuel to fat burn, a state called metabolic switching. This may help to support stable blood sugar and overall metabolic health. We are all individuals, and fasting does not suit everyone, so the best approach is to try small changes and see what feels sustainable and helps you personally.”

Katie Murray, a nutritionist at AltruVita, a gut supplement brand, agreed that fasting can help certain people stabilise their blood sugar by giving the body a break from processing foods, particularly carbohydrates, which helps the body use insulin more effectively by reducing large sugar spikes.

She continued: “When you’re fasting, insulin levels drop, which supports cells moving sugar out of the blood more efficiently when you do eat. However, fasting is not safe for everyone, in particular those on certain diabetes medication, people who suffer from drops in blood sugar levels frequently, or people under significant amounts of stress.”

However, she warned that there are risks for diabetics, especially without guidance. “These include dramatic spikes or drops in blood sugar levels, dehydration and raised cortisol levels (stress hormone) causing instability of blood sugar levels,” she said.

“When fasting with conditions such as diabetes, it is very important to monitor yourself carefully and to ensure you have adequate medical support and guidance.”

Superdrug’s Online Doctor, Dr Babak Ashrafi agreed that fasting can help stabilise blood glucose levels for some people by reducing insulin spikes and improving insulin sensitivity. He explained that this happens because during periods without food, the body shifts from using glucose to using stored energy, which can lead to more stable blood sugar levels over time.

He added: “Some forms of intermittent fasting have been shown to reduce fasting glucose and improve metabolic markers in people without diabetes or with insulin resistance. However, the response to fasting varies significantly between individuals, and it’s not universally beneficial.”

He also said there are some important risks to take into consideration if you’re diabetic. “Fasting can increase the likelihood of hypoglycaemia (dangerously low blood sugar), particularly in people taking insulin,” he said.

“It may also lead to hyperglycaemia if medication is adjusted incorrectly, as well as dehydration or electrolyte imbalances. In some cases, fasting can make blood sugar levels more unpredictable rather than more stable. This is why fasting should never be undertaken by people with diabetes without medical guidance and regular blood glucose monitoring.”

Superintendent pharmacist, Abbas Kanani, MRPharmS at Chemist Click, agreed that fasting can help stabilise blood glucose by giving the body a break from constant food intake, which reduces blood sugar spikes and can improve insulin sensitivity. However, it isn’t suitable for everyone as it also carries risks, such as hypoglycaemia, dizziness, or fatigue, especially for those on insulin or other glucose-lowering medications.

Nutritionist Ed Tooley from The Turmeric Co said fasting has become extremely popular, with many people using strategies such as intermittent fasting or 48-hour fasts.

He added: “One reason some people do this is because they find that fasting helps to stabilise blood glucose levels by reducing post-meal fluctuations, making blood sugar patterns more predictable. However, this is not a one-size-fits-all approach. Seeing a nutritionist to learn about the effectiveness of fasting within your own lifestyle and diet is vital.”

Not everyone agrees that fasting is the best option for diabetics. Tobias Mapulanga, co-founder of Repose Healthcare, said that fasting introduces a tighter margin for error in Type 1 diabetes, rather than offering a universal benefit.

He continued: “Basal that is even slightly too high can drive hypoglycaemia without the cushioning of snacks, while cutting insulin too far can allow ketones to rise even if glucose is not very high. Bigger, compressed meals in strict 8‐hour windows can cause larger post‐prandial spikes and more variability than evenly spaced meals. Hormonal stressors, exercise, and illness can swing glucose faster when you are fasting, and medication timing may become awkward.”

He said that there isn’t much evidence that fasting is effective for Type 1 diabetics and that individual responses to it vary. Instead, he said that for some people, a regular meal pattern with a good amount of protein, fibre, and matched insulin is “simpler and gives more stable results than formal fasting”.

For those who are considering fasting with Type 1 diabetes, he suggests speaking with your diabetes team first and avoiding fasting if you have had a recent hypoglycaemic event or Diabetic ketoacidosis, are pregnant, have an eating disorder, do heavy manual work or are unwell.

If you do plan on attempting fasting with Type 1 diabetes, the expert recommends: “Never stop basal insulin, use a CGM with alerts on and review settings if you use an automated insulin delivery system, stay well hydrated, and check blood or breath ketones if glucose is high or you feel unwell; always carry rapid‐acting carbohydrates and glucagon.

“Be especially cautious if you take an SGLT2‐type medicine because it raises ketoacidosis risk, including when glucose is not very high. Start with a consistent overnight fast of 10–12 hours and keep regular daytime meals, avoiding prolonged or alternate‐day fasts at least initially. Break the fast if glucose is below 4.0 mmol/L or dropping quickly, if you need repeated treatments for lows, or if glucose stays above 14 mmol/L with ketones or symptoms, which keeps potential benefits while minimising real risks unique to Type 1 diabetes.”

While fasting works for me, I understand this isn’t an option for everyone. Before attempting fasting or making any changes to your diet or lifestyle, it’s best to consult your GP.