Tips on how to prevent type 2 diabetes
A new study suggests that a fasting regimen could reduce the risk of the disease - along with your biological age.
Could dieting for five days a month be enough to preserve health and help prevent you from getting type 2 diabetes? That is the claim of a group of scientists from the University of Southern California (USC) reporting in the journal Nature Communications this week. According to Valter Longo, professor of biological sciences and director of the Longevity Institute at USC, practising a so-called fasting-mimicking diet (FMD) that is low in calories, protein and carbohydrates, and designed to mirror the effects of a water-only fast, for five days resulted in a lower biological age and a reduced risk of getting type 2 diabetes for participants in his study.
For the trial Longo and his colleagues asked 100 people aged 18 to 70 to stick to FMD, comprising carefully controlled plant-based soups, energy bars, energy drinks, snacks and tea, as well as a multivitamin supplement, for five days followed by 25 days of eating normally, and to repeat the cycle three or four times over three to four months. Patients in the control groups ate either a normal or a healthy Mediterranean-style diet with plenty of fish, fruit and vegetables. When the scientists compared blood samples taken at the end of the study with those taken at the start, they found that people on the FMD diet not only had reduced levels of abdominal fat and fat within the liver, but that type 2 diabetes risk factors, including insulin resistance and blood sugar levels, had improved, suggesting it could be a game-changer for the condition.
Often dubbed a silent killer, type 2 diabetes is seen as an insidious threat to health that is increasing at an unprecedented rate. According to the charity Diabetes UK, the number of people with the condition is at “an all-time high”, with an estimated 4.3 million people in the UK diagnosed with diabetes, about 90 per cent of whom have type 2. In addition, many more are unaware they have it: figures released this week by the Office for National Statistics suggest that as many as one million adults in England are living with undiagnosed type 2 diabetes, with poor diet habits and obesity blamed for the surge.
Type 2 diabetes occurs when blood sugar levels are consistently too high. In a healthy person, the pancreas produces enough insulin to allow the body to use the sugar or store it appropriately but in someone with type 2 diabetes, that system breaks down. “Either the pancreas doesn’t make enough insulin or the insulin it does make is inefficient,” says Roy Taylor, professor of medicine and metabolism and a type 2 diabetes researcher at Newcastle University. “This so-called insulin resistance causes a build-up of sugar in the blood, leading to symptoms of type 2 diabetes and its associated health consequences.”
Both a nutritious diet and maintaining a healthy weight are crucial to its prevention and treatment. “Type 2 diabetes is usually caused by a prolonged and excessive consumption of calories over many years,” Taylor says. “It reaches a point when insulin-producing cells inside the pancreas are damaged by accumulated fat to such an extent that they stop working as they should, but weight loss and positive changes to diet can always counter this harmful effect to some extent.”
He says the positive effects of the FMD are likely down to weight loss and weight control rather than some magical property of the diet itself. “This was a small and short study involving 100 people, most of whom were a healthy weight to start with, over three months so we can’t extrapolate too much from the data, but it does underline the importance of weight loss for health improvements.”
Taylor says that while it is never too late to tackle type 2 diabetes, if you choose to ignore it, the consequences can be catastrophic. Over time, chronically raised blood sugar levels can damage blood vessels that supply oxygen to the body, raising the risk of poor circulation, heart disease, kidney damage and a long list of other harmful health problems. Here’s what you need to know to reduce the risks:
What are the symptoms of type 2 diabetes?
According to the NHS these can include tiredness, getting up to use the loo at night, feeling unusually thirsty and blurry vision. But the condition can also creep up silently. Taylor says that people can be living in the “grey zone” of pre-diabetes for many years without even realising it. Pre-diabetes is defined as the point at which your blood sugar is higher than it should be and your body has too much internal fat but without any obvious symptoms. “Pre-diabetes is often ignored or overlooked yet the risk of having a heart attack or stroke is greatly raised with it,” he says. “Taking control of diet and weight at this stage can save a lot of health heartache down the line.”
How is type 2 diabetes diagnosed?
Most cases of type 2 diabetes are picked up in routine health checks or when people are seeking medical advice for other conditions. A test will also be offered if you have a family history of the disease. “A GP or nurse will conduct an HbA1C blood test, usually taken from a vein in the arm, that assesses your average blood sugar levels over the previous two to three months,” says Keren Miller, dietician and clinical lead at the NHS weight management provider Oviva. “If HbA1C levels are between 42-48 mmol/mol you have pre-diabetes and above 48 mmol/mol indicates type 2 diabetes.” Don’t try self-diagnosis: according to Diabetes UK, DIY “finger prick” home testing kits will confirm if you have high blood sugar, not that you have diabetes.
Do you have to be overweight to get it?
You may look slim but still have higher amounts of fat than your body can handle. In fact, one in ten people diagnosed with type 2 diabetes has a “healthy” BMI in the range of 18.5 to 24.9. What matters, Taylor says, is your personal fat threshold (PFT), which is genetically determined and influences how fat is stored in your body. “If you exceed your PFT and acquire more body fat than is healthy for you as an individual, it is asking for trouble,” Taylor says. “Excess fat starts to spill over into the liver and pancreas, and begin to affect the ability of your internal organs to control blood sugar.” He says we should take a hard line on weight control. “Really your waist circumference and weight in adulthood should remain the same as healthy measurements in your twenties,” Taylor says.
Are women more at risk than men?
Type 2 diabetes affects both men and women but because it tends to strike at a lower BMI in men there are slightly more UK adult males with the condition. “A tendency for men to put on weight around the middle is a risk factor so keeping tabs on waist measurement is crucial,” Miller says. Changes in levels of the hormones oestrogen and progesterone around the menopause can lead to weight gain around the middle and blood sugar fluctuation in women, meaning their risk rises with age.
Is type 2 diabetes reversible?
In his own diabetes remission clinical trials (known as DiRECT), published in The Lancet’s Diabetes & Endocrinology journal, Taylor showed that it is possible to reverse type 2 diabetes using a diet that restricts intake to 700-800 calories a day in the form of meal replacement soups and shakes. Almost half (46 per cent) of people with the condition who took part in Taylor’s original research were in remission after one year and 64 per cent of participants who lost more than ten kilos were in remission at two years. In a three-year extension of the study, Taylor and his team found that nearly a quarter (23 per cent) of those remained in remission at five years. So successful is the diet, now known as the T2DR (type 2 diabetes remission) approach, that it is widely prescribed on the NHS. “It involves 12 weeks of consuming only diet replacement soups and shakes, followed by six weeks of guided food reintroduction and behaviour therapy,” Miller says.
Will you need to lose weight?
Some weight loss is likely essential if you have been diagnosed with type 2 diabetes, although how much depends on your genetics and body shape. “Most people diagnosed with the condition will need to shed about 15kg, or 2.5st, in weight, which will also shift harmful fat from their internal organs,” Taylor says. “If you are slightly built and weigh less than 12.5st but have been told you have type 2 diabetes, you should aim to lose about 10 per cent of your body weight, or 1.5st.” With adequate weight loss, it is likely that your blood sugar control will return to normal.
Are drugs another option?
If you have had type 2 diabetes for more than six years or are not suitable for the T2DR approach then medication is an option. This includes tablets such as metformin to lower your blood sugar. They are safe but do have possible side-effects, including dizziness and fluid retention at the ankles. While they treat the problem, they will not reverse it. Ozempic, the brand name for the drug semaglutide, is also an option.
Are diabetic foods the way forward?
As the incidence of type 2 diabetes has risen, so has the market for processed foods that claim to help people reduce their risk of the condition. Miller says they are far from essential and in many cases are best avoided. “You would be far better off targeting more fibre from whole grains, fresh vegetables, beans and legumes, which are all associated with a lower incidence of type 2 diabetes,” she says.
How important is exercise?
Physical activity helps to lower blood sugar and is an essential part of type 2 diabetes prevention. Aim for at least 150 minutes a week of moderate aerobic activity, such as walking, cycling and swimming, as well as some resistance training. In a study of 4,681 adults who had no type 2 diabetes when they joined the trial, researchers reported in the journal Mayo Clinic Proceedings that lifting weights reduced their risk of developing type 2 diabetes by 32 per cent. “Try to do as much varied physical activity as you can,” Miller says.
The Times
