Trendy intermittent fasting diets promoted by Jennifer Aniston and Reese Witherspoon are ‘no better for weight loss’ than eating the same meals throughout the day, study finds
- The diet is to limit the time you eat to eight hours every 24 hours
- Researchers set up a randomized clinical trial to see if the diet works
- The volunteers followed a time-limited diet for 12 weeks and reported their weight
- A control group ate three meals a day at normal times of the day for 12 weeks
- The team found no difference in the rate of weight loss between the two groups
The diets made famous by Jennifer Aniston and Reese Witherspoon that force you to limit your diet are “ no better for losing weight ” than eating normally.
Researchers at the University of California, San Francisco asked a group of 116 volunteers to eat a celebrity-inspired fasting diet and others ate three meals a day.
The fasting group could only eat between 12 p.m. and 8 p.m. and the other could eat when they wanted – there were no restrictions on what food people could eat.
Although both saw a slight drop in weight, neither was significantly different from the other group – suggesting that a daily “ fasting time ” makes no difference.
Time-limited eating, or intermittent fasting, involves limiting the time to eat to a smaller part of the day and is favored by celebrities as a weight loss solution.
In October 2019, Jennifer Aniston said she skips breakfast and only consumes fluids in the morning, which keeps her from eating until the last half of the day.
Diets made famous by Jennifer Aniston (pictured) and Reese Witherspoon that force you to limit when you eat are ‘no better for losing weight’ than eating normally
The University of California team investigated whether this form of diet control could actually help reduce weight compared to a daily diet.
It was hoped that if it was found to be effective for weight loss, it could be a relatively easy lifestyle change for obese people to implement and lose weight.
“Even modest weight reduction can improve the risk of cardiovascular disease,” they wrote.
“However, long-term adherence to lifestyle changes is difficult. Therefore, it is important to find new lifestyle modification interventions that are effective in reducing weight and accessible and straightforward in improving adherence.
They looked at intermittent fasting, the eating process separated by defined periods of fasting – typically 12 hours every 48 hours.
Unfortunately, most of the claimed benefits for this diet method have not been tested or under-tested in humans, the authors say.
To test their theory that it could improve weight loss, they focused on the time-restricted diet – also known as 16: 8 – which was found to be effective in mice.
This involves a period of constant fasting and eating over the course of a day – usually eight hours of meals for 16 hours of fasting.
Each volunteer received a Bluetooth scale and asked to record their weight each day. There was no noticeable difference between a time-limited diet (yellow) and a normal diet (blue)
Previous small-scale studies in overweight people found that eating for a limited period of time could lead to reduced calorie intake and decreased body weight.
To see if this holds up with a larger group, the team designed a randomized clinical trial to determine the effect on overweight and obese patients.
Volunteers followed the new diet for 12 weeks and responded to a survey throughout the process, recording their weight on Bluetooth scales provided by the university.
The study only limited the time to eat the food, not what people ate or any other physical activity during the study – it was just a test of eating windows.
They found that people were able to stick to the time-restricted diet successfully, giving credence to the idea that it would be a viable solution to losing weight.
Celebrities like Reese Witherspoon (pictured) use diets like the 16: 8 time-limited eating method – but studies suggest it can be just as good to eat throughout the day
Unfortunately, there was no greater weight loss with this method than among those who ate three meals a day without any time restrictions.
The researchers say there was also some evidence that eating a time-limited diet could exacerbate muscle loss – particularly appendicular lean mass (ALM).
The team says future studies should aim to understand the effects of early or late restricted eating, as the time spent eating can have an impact.
They also want to see if an increase in protein intake or at different times of the day could limit the loss of ALM.
The results were published in the journal JAMA Internal Medicine.
THE 16: 8 DIET: EAT FOR EIGHT HOURS A DAY
The 16: 8 diet is a form of intermittent fasting, also known as time-limited eating.
Followers of the diet fast 16 hours a day and eat whatever they want in the remaining eight hours, usually between 10 a.m. and 6 p.m.
This may be more tolerable than the well-known 5: 2 diet – where followers limit their calories to 500-600 per day for two days per week, then eat normally 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 8 p.m., as that means they only need to fast overnight and skip breakfast, but can still have lunch and dinner, with a few snacks.
When eating out, it’s best to go for healthy options like fruits, vegetables, and whole grains.
And drink water and unsweetened drinks.
The downsides of the fasting plan can be that people abuse the hours when they can eat, resulting in weight gain.
It can also lead to long-term digestive issues, as well as hunger, fatigue, and weakness.