Combining HIIT exercises with a strict 6pm dinner cut-off could help you lose twice as much weight, a study suggests.
Overweight and obese women who stuck to the strategy for seven weeks lost 3.6kg (7.9lbs) on average.
For comparison, volunteers asked to just adhere to a time-restricted diet, where all daily meals could only be consumed within a 10-hour window such as 8am-6pm, lost 2.1kg (4.6lbs).
And participants who only took part in the brutal exercises, which can involve push-ups, burpees and squats interspersed with intervals of rest, lost almost 1.7kg (3.7lbs).
Asked if the simple fat-fighting strategy worked, one Norwegian academic behind the research unequivocally answered ‘yes’.
While participants in the Norwegian study could eat whatever they wanted and as much as they wanted, there was one catch. Their entire calorie intake had to take place within a ten-hour maximum time window
Hollywood A-listers like Jennifer Aniston and Mark Wahlberg (pictured above) have all jumped on the intermittent fasting trend since it shot to prominence in the early 2010s
It adds to the mountain of research praising the benefits of time restricted eating, or intermittent fasting.
Hollywood A-listers like Jennifer Aniston, Nicole Kidman and Mark Wahlberg have all jumped on the trend since it shot to prominence in the early 2010s.
Q+A: Everything you need to know about intermittent fasting
How does it work?
Intermittent fasting involves switching between days of fasting and days of eating normally.
It generally falls into two categories – narrowing eating times to 6-8 hours per day, also known as the 16:8 diet, and 5:2 intermittent fasting.
The 16:8 diet is a form of intermittent fasting, also known as Time Restricted Eating.
What is the difference between time restricted eating and 5:2 intermittent fasting?
Followers of the 16:8 eating plan fast for 16 hours a day, and eat whatever they want in the remaining eight hours – typically between 10am and 6pm.
This may be more tolerable than the well-known 5:2 diet – where followers restrict their calories to 500–to-600 a day for two days a week and then eat as normal for the remaining five days.
What are the benefits of Time Restricted Eating?
In addition to weight loss, 16:8 intermittent fasting is believed to improve blood sugar control, boost brain function and help us live longer.
Many prefer to eat between noon and 8pm as this means they only need to fast overnight and skip breakfast, but can still eat lunch and dinner, along with a few snacks.
When you do eat, it is best to opt for healthy options like fruits, vegetables and whole grains.
And drink water and unsweetened beverages.
What are the drawbacks?
Drawbacks of the fasting plan may be that people overindulge in the hours they can eat, leading to weight gain.
It can also result in digestive problems over the long-term, as well as hunger, fatigue and weakness.
But, despite swathes of studies suggesting it works, experts remain divided over its effectiveness.
Some argue that fasters usually end up consuming a relatively large amount of food in one go, meaning they don’t cut back on their calories — a known way of beating the bulge.
They even warn that it may raise risk of early death.
The new Norwegian University of Science and Technology study, published in Cell Metabolism, involved 131 women aged 19 to 45.
All four groups, which included a control set that ate and exercised normally, were equally sized.
Each HIIT session, involving 4x4minute and 10x1minute interval training, lasted 35 minutes.
Participants took part three times every week. During each session, they trained at over 90 per cent of their maximum heart rate.
Volunteers asked to eat within a 10-hour window were not asked to scale back what they consumed, just when they ate.
As well as losing more weight, the combination group saw ‘superior reductions in total and visceral fat mass’.
Visceral body fat, also known as ‘hidden’ fat, is the most dangerous type of fat that wraps around your abdominal organs.
But that wasn’t the only benefit.
Volunteers in the combination group saw the biggest drop in blood sugar levels and improvement in oxygen intake.
High blood sugar levels and low oxygen levels are both markers of cardiometabolic diseases – a group of common but often preventable conditions including heart attack, stroke, diabetes, insulin resistance and non-alcoholic fatty liver disease.
Cardiovascular disease (CVD), which includes heart attacks and strokes, kills more people across the world than any other illness.
The World Health Organization estimates 18million people are killed by the condition every year, accounting for over 30 per cent of all global deaths.
In the UK, CVD is responsible for a quarter of all deaths, or around 160,000 deaths each year.
In the US, CVD contributes to every one in five deaths — or around 697,000 — each year, according to the Centres for Disease Control and Prevention.
Dr Trine Moholdt, who led the study, said: ‘Numerous studies have shown positive health effects of time-limited eating and HIIT individually.
‘We wanted to see if combining these two lifestyle changes is more effective than just one of them alone. Few previous studies have done that.’
She said: ‘The risk of losing weight without exercising is that you’ll lose a lot of muscle mass, which isn’t advisable.
‘Starting with both time-limited eating and high-intensity interval training can be a good idea if you want to quickly improve your health and reduce the risk of disease.’