A fashionable time-restricted diet, combined with high-intensity exercise, could help women lose twice as much weight.
Time-restricted eating (TRE), where people have a short ‘window’ for meals, eating breakfast late and dinner early, is popular among celebrities like Jennifer Aniston.
Equally trendy is high-intensity interval training (HIIT), where busy people exercise in short bursts.
Now a study has found both together may help women lose about twice as much weight as either TRE or HIIT on their own.
Time-restricted eating (TRE), where people have a short ‘window’ for meals, eating breakfast late and dinner early, is popular among celebrities like Jennifer Aniston (pictured arriving at a premiere for the Murder Mystery film in Los Angeles, June 2019 )
WHAT IS HIGH INTENSITY INTERVAL TRAINING?
HIIT describes any workout that involves short burst of high-intensity exercise followed by a brief low-intensity activity, repeatedly.
The medium exercise should be about 50% intensity. The number of repetitions and length of each depends on the exercise, but may be as little as three repetitions with just 20 seconds of intense exercise.
There is no specific formula to HIIT. A common method involves a 2:1 ratio of work to recovery periods, for example, 30-40 seconds of hard sprinting alternated with 15-20 seconds of jogging or walking, repeated to failure.
The entire HIIT session may last between four and 30 minutes, meaning that it is considered to be a good way to maximize a workout in a short time.
Researchers recruited 131 overweight women, aged 19 to 45, asking a quarter to do time-restricted eating, a quarter to do HIIT, and a quarter to do both, for seven weeks in total.
The rest of the women — a control group of 33 — carried on with their usual diet and physical activity for seven weeks.
Compared to the control group, people on the time-restricted eating regime lost 4.6 pounds (2.1kg) in body weight.
Those doing high-intensity walking or running (HIIT) lost almost four pounds (1.7kg).
But those doing both together lost about twice as much, shedding almost eight pounds (3.6kg) on average compared to the control group.
The researchers say eating for a shorter period each day means people cut the calories they consume, but exercise is important too, as it helps the body burn fat more efficiently.
Dr Trine Moholdt, senior author of the study from the Norwegian University of Science and Technology, said: ‘High-intensity exercise can be done quickly over a short period, so fits into the day more easily.
‘Time-restricted eating is simple, as people just have to remember not to eat after a certain time, rather than having to turn down certain foods, count calories, or check food labels.
‘Our findings suggest both strategies together are a good way to lose weight and fat.’
Equally trendy is high-intensity interval training (HIIT), where busy people exercise in short bursts
What IS intermittent fasting?
Intermittent fasting involves switching between days of fasting and days of eating normally.
Intermittent fasting diets generally fall into two categories – time-restricted feeding, which narrows 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.
Followers of the 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.
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.
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.
The study, published in the journal Cell Metabolism, asked people doing time-restricted eating to consume all meals and snacks within a 10-hour daily window.
The female volunteers had their breakfast more than an hour later than usual, on average, and typically followed the study recommendation to eat their last meal of the day before 8pm.
Experts say the human body clock means we process sugary food better earlier in the day.
Indeed, people who did the time-restricted diet and high-intensity exercise had better long-term blood sugar control compared to the control group, which may help to prevent type 2 diabetes.
But, importantly, the women unable to eat and snack late into the evening also cut their average food intake by the equivalent of 1,400 calories a week.
Women on the time-restricted diet lost 3.5 pounds (1.6kg) of fat from their body, compared to the control group.
However those on both the diet and the exercise program lost almost twice as much fat, shedding almost seven pounds (3.1kg) compared to the control group.
Women doing HIIT burned 800 calories a week on average, the researchers found.
The high-intensity exercise in the study consisted of three sessions of approximately 35 minutes a week.
Women ran or walked on a treadmill, or up a hill, at a speed and gradient which got their heart beating very fast and made them out of breath.
Those doing this HIIT alongside the time-restricted diet had a significant reduction in dangerous fat wrapped around their organs, which is linked to a higher risk of heart disease and stroke, compared to the control group.
This reduction was half as high in those doing the diet alone.
No difference was found in cholesterol levels or blood pressure, among those doing HIIT and TRE, but the researchers say there could be stronger effects if people did the diet and exercise for longer than seven weeks, or were more unhealthy to start out with.
Dr Moholdt said: ‘This was easy to stick to, with women managing the diet on six out of seven days, and managing the exercise.
‘They also became fitter from HIIT, making everyday physical activity easier, so we recommend this kind of program for people who wish to have a relatively simple way of changing diet and exercise habits and improving their health.’
WHAT SHOULD A BALANCED DIET LOOK LIKE?
Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain, according to the NHS
• Eat at least 5 servings of a variety of fruit and vegetables every day. All fresh, frozen, dried and canned fruit and vegetables count
• Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain
• 30 grams of fiber a day: This is the same as eating all of the following: 5 servings of fruit and vegetables, 2 whole-wheat cereal biscuits, 2 thick slices of wholemeal bread and large baked potato with the skin on
• Have some dairy or dairy alternatives (such as soya drinks) choosing lower fat and lower sugar options
• Eat some beans, pulses, fish, eggs, meat and other proteins (including 2 portions of fish every week, one of which should be oily)
• Choose unsaturated oils and spreads and consuming in small amounts
• Drink 6-8 cups/glasses of water a day
• Adults should have less than 6g of salt and 20g of saturated fat for women or 30g for men a day
Source: NHS Eatwell Guide