A new study is casting doubt on the allure of intermittent fasting.
The research, which evaluated more than 100,000 adults over nine years, claims that eating breakfast before 8am can reduce the risk of developing Type 2 diabetes by 59 per cent or, equally, eating the first meal later in the day can increase the risk of the disease.
This claim directly challenges one of the most popular diets of our time – intermittent fasting, which usually involves skipping breakfast. People tend to have their first meal later in the day, so the eating window extends to a reasonable time in the evening.
The confusion arises because, in the past, several studies have claimed that intermittent fasting can actually help to prevent Type 2 diabetes, with one 2014 study published in the medical journal Translation Research reporting that the blood sugar levels of diabetics who practised intermittent fasting dropped by up to 6 per cent, while fasting insulin was reduced by 20 to 31 per cent.
Skip breakfast at your own risk
The latest study, published in the International Journal of Epidemiology in June, investigated the link between meal frequency and timing, and the chances of developing Type 2 diabetes among 103,312 adults.
Participants were asked to record what they ate and drank over a 24-hour period on three non-consecutive days, as well as the timing of their meals. Researchers averaged these records for the first two years, and assessed participants' health over the next seven years.
About 960 new cases of Type 2 diabetes emerged during the study, with the risk higher in the group of people who ate breakfast later. “Biologically, this makes sense, as skipping breakfast is known to affect glucose and lipid control, as well as insulin levels,” said co-author Anna Palomar Cros.
The research also found that eating dinner after 10pm increased the risk further, while eating about five times a day was linked to lower disease incidence.
Based on this, co-author Manolis Kogevinas said it is suggested to have the first meal by 8am, and the last before 7pm to help reduce the risk of developing the disease.
The intermittent fasting conundrum
If people who follow intermittent fasting bump their eating periods earlier in the day, in line with the study's conclusion, this could mean the last meal would be taken at, by or before 3pm.
However, Ayaz Ahmed, an internal medicine specialist at Aster Cedars Hospital in Jebel Ali, says this might not be ideal.
Speaking to The National, he says he would still advise patients who are intermittent fasting to start their meal later in the day “to sustain their energy levels throughout”.
“People need energy to do their jobs and to socialise, and it's not practical to restrict the eating period that early on in the day,” he says.
After all, he reiterates, the goal of such dieting techniques is to ultimately live a healthier lifestyle. Skipping dinner, Ahmed adds, might result in poor quality sleep or overeating the next day, which would defeat the purpose of the diet.
“It's also about commitment and being able to maintain the diet,” he says, adding it will be difficult to do so if the diet gets in the way of accomplishing daily tasks during the day because of hunger or exhaustion.
“Skipping breakfast is more practical, and fasting will be easier to sustain in this case.”
Diabetes and fasting
Ahmed clarifies his advice is generally applicable to people who have not been diagnosed with Type 2 diabetes. Diabetics who are on long-term therapy and are taking medications should approach any dieting method with caution.
Part of the reason why time-restricted eating has become popular is its weight-loss effect, which is a crucial element in managing blood sugar levels. “Losing even a small amount of weight can help improve your blood sugar control, blood pressure and cholesterol levels along with diabetes,” clinical dietitian Mitun De Sarkar tells The National.
Even so, she adds, while intermittent fasting has been proven to aid in losing weight, it could be detrimental for diabetics, especially those who are on medication.
“There have been several studies in the past that showed diabetics who ate regular meals and snacks throughout the day had better blood sugar control than those who did not,” she says.
“In most instances, diabetics need their medication taken with their meals for better effectivity, which can be a challenge when fasting for long periods,” she says, adding one of the risks of intermittent fasting for diabetics is hypoglycaemia, when blood sugar levels drop too low.
De Sarkar says breakfast plays an important role for such group, and when it is skipped, the “body goes into 'starvation mode', which can lead to a spike in blood sugar levels later in the day”.
“When you eat breakfast, your body releases insulin, which helps to move glucose from the bloodstream into your cells. This helps to keep your blood sugar levels from spiking.”
She says human metabolism works more efficiently in the morning, and suggests not skipping breakfast, eating dinner early and starting the fast at night time instead.
“We are not meant to eat late in the night. It is against our body's circadian rhythm,” she says, referring to people's natural body clock.
The dinner or last meal should be high in fibre, have about 30g of proteins and good fat content, De Sarkar says, to avoid being hungry by bedtime.
On whether intermittent fasting is just a fad, she says it is a “matter of opinion”, and that more research is needed to determine its long-term effects.
No one size fits all in dieting
Ruba Elhourani, senior clinical dietitian and the head of the nutrition department at RAK Hospital in Ras Al Khaimah, says whichever eating method people choose, meals must always be balanced to achieve results.
She says for diabetic patients, it's important to be aware of carbohydrates and sugar intake.
This is echoed by Velmurugan Mannar, a specialist endocrinologist at Aster Clinic Silicon Oasis, who says patients need to “consider all the practical issues and sustainability” before committing to any diet plan.
Instead of setting eating time restrictions, he advises patients do a low-carbohydrate, low-fat diet, incorporating more protein and fibre in their meals.
De Sarkar says “in the diet world, one size never fits all, and there is no ideal way of eating for diabetics. It all depends on an individual's specific needs, lab investigations, blood work and lifestyle preferences.
“It is also important to note that intermittent fasting is not a magic bullet for weight loss,” she adds. “If you want to lose weight and keep it off, you need to make changes to your diet and lifestyle, and can’t eat what you wish in the eating window. If you are diabetic and considering trying intermittent fasting, it is important to talk to your endocrinologist or a clinical dietitian first.”