Fasting diets are better for weight loss than simply trying to cut calories, according to a study in patients with type 2 diabetes.
Limiting the “eating window” to an eight-hour period between 12pm and 8pm helped people to lose nearly 4 per cent of their body weight over a six-month period.
However, patients who were told to cut their daily calories by 25 per cent did not see any significant weight loss. Experts said “counting time is easier than counting calories”, and people find it harder to stick to diets if they are allowed to eat at all times of the day. The six-month trial by US researchers involved 75 obese patients with diabetes who were divided into three groups: intermittent fasting, calorie reduction and a control group.
Those on the intermittent fasting diet reduced their food intake by 313 calories per day on average, while the calorie reduction group reduced their intake by 197 calories a day.
Both groups saw improvement in their blood sugar levels compared with the control group, but the weight loss was only significant in the fasting group.
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The study, published in JAMA, is the largest trial to date looking at whether intermittent fasting is an effective option for patients with type 2 diabetes.
Fasting diets have boomed in popularity in recent years and are popular with celebrities including Hugh Jackman and Jennifer Aniston. People can eat whatever they want, with no limits on calories, as long as eating is restricted to a few hours each day.
The research suggests intermittent fasting could also be recommended on the NHS for millions of patients with type 2 diabetes, a condition closely linked with obesity.
Dr Krista Varady, the lead author from the University of Illinois Chicago, said: “Our study shows that time-restricted eating might be an effective alternative to traditional dieting for people who can’t do the traditional diet or are burned out on it. For many people trying to lose weight, counting time is easier than counting calories.”
She said that many patients with type 2 diabetes will have already tried — and failed — to lose weight by cutting back their calories, so new options were desperately needed.
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Five million Britons have diabetes, which occurs when a person’s blood sugar becomes chronically high as the body stops producing or responding to the hormone insulin. Nine in ten cases are type 2 and this can cause complications including heart disease, stroke, eye problems and kidney failure
Rapid weight loss has been shown to put type 2 diabetes into remission and the NHS is rolling out a radical “soup and shakes” diet plan for people with the disease.
Dr Faye Riley, from Diabetes UK, said: “This intriguing study shows that limiting normal food consumption to a eight-hour window during the day helped people with type 2 diabetes lower their blood sugar levels and lose weight in the short-term. This adds to emerging evidence that going for longer periods without eating, known as time-restricted eating, may benefit some people with the condition.
“We now need larger and longer-term clinical trials to understand whether this style of eating can help people manage their type 2 diabetes and weight over the longer term, before recommendations about time-restricted eating as an add-on strategy for people with type 2 diabetes can be made.
“It’s important to remember that there’s no one diet for type 2 diabetes, and the best diet is one you can stick to. If you’re living with type 2 diabetes and are trying to lose weight, having the right support is also crucial. Starting a new diet may affect your medication or blood sugar levels, so it’s important to speak you your healthcare team first before making any changes to your diet.”
