I was diagnosed with Type 1 diabetes at the age of nine and have tried many 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. It means I have to inject myself with insulin multiple times a day. 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. I 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.
And I've come to realise that one regular habit keeps them particularly well-balanced: fasting. 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.
Breakfast made my blood sugar spike quite rapidly — followed by a crash
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."
Shaky hands, sweating, hunger and anxiety
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: "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. 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."
And 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."
Fasting works for me
It's a theme repeated by other people in the field. And while 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, she also 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."
And 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: "Bigger, compressed meals in strict eight-hour windows can cause larger postprandial 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".
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.
