Yo-yo dieting isn't as bad as you think
Even if you regain some lost weight, you'll still cut your risk of heart disease
You've tried them all. Diets work for a bit, then all those lost pounds pile right back on as soon as you stop. Disappointing, but there's also the concern that “yo-yo” dieting — repeatedly losing then regaining weight — has traditionally been seen as something potentially dangerous.
Hapless dieters are warned that if they regain, they may end up fatter and less healthy than before they began. But now a new analysis has found people who lost weight — despite the lost pounds creeping back on — saw benefits to their health for at least five years.
Researchers at Oxford University looked at 124 trials involving around 50,000 people trying to lose weight. Around half of the dieters took part in behavioural weight-loss programs which supported lifestyle changes such as eating healthier food and doing more exercise. The rest went alone.
At the start, they had an average age of 51 and a BMI of 33, which is considered obese. They lost an average of between five and 10 pounds (or 2-5 kg), and typically regained at a rate of less than a pound a year.
Susan Jebb is a public health nutrition scientist at the University of Oxford, and a co-author of the study. “Many doctors and patients recognize that weight loss is often followed by weight regain, and they fear that this renders an attempt to lose weight pointless,” she says. “This concept has become a barrier to offering support to people to lose weight.”
In a 2018 analysis of 29 longterm weight loss studies, more than half of the lost weight was regained within two years, and by five years more than 80 per cent of the painstakingly shed pounds had piled back on.
But as this new study shows, that doesn't mean dieting was futile — instead of causing metabolic carnage or triggering eating disorders, even “failed” weight loss seemed to leave people healthier.
“In our study, weight regain, on average, took at least five years, and sometimes up to 14 years to regain,” says Jebb. During the time your weight is lower, your blood pressure, blood glucose and cholesterol levels are lower. These are all risk factors for heart disease, so it's very probable your long-term risk of diabetes and heart disease is lower, too.
“We can't be absolutely certain because few studies have followed people up long term, but putting information from all the studies together, the trend is very clearly toward fewer cases of diabetes and heart disease among people in the group offered a weight-loss program.”
This study adds to evidence showing being lighter — even for short periods — seems to improve longer term health.
Jebb points out the study didn't look at yo-yo dieting per se but, she says, “we found no evidence of harm to physical or mental health during or after a period of weight loss and regain.”
But doesn't yo-yo dieting make us flabby by reducing our muscle mass and replacing it with fat — something that might slow our metabolisms further?
A study published in the journal Nature in 2020 suggested while this might be true of slim people who repeatedly diet to become even skinnier, it may not apply to people who are overweight.
And according to Johns Hopkins School of Medicine in the U.S., yoyo dieting will not make it harder to lose weight in future.
“Most studies show that weight cycling does not affect the rate at which the body burns fuel,” it states. Also, a previous weight cycle does not influence the ability to lose weight again, or increase the amount of fat tissue or increase fat distribution around the stomach.
And in 2019, a mouse study found that mice subjected to several rounds of yo-yo dieting lived as long as mice kept at a stable weight on a low-calorie diet and much longer than steadily obese mice.
Diabetes researcher and GP Simon Tobin co-authored a study showing that half of people with Type 2 diabetes could put their disease into remission with the help of a low-carbohydrate diet.
He points out some patients lost just 1kg of weight (around 2 lbs), or less on the diet “but still managed to put their Type 2 diabetes into remission. That shouts out to me it cannot be weight loss alone that has achieved this.”
On the other hand, relying on new weight loss medications such as Ozempic or Wegovy without lifestyle support may leave people particularly vulnerable to yo-yoing.
Jebb says, “There is some preliminary evidence from individual studies that weight regain after weight-loss medication is stopped may be faster than after diet and exercise programs.”
One of Tobin's co-authors, Roy Taylor, is a professor of medicine and metabolism conducted a study showing that an 800-calorie-a-day liquid diet can reverse diabetes in many patients. Taylor says that half of the successful study participants needed to tackle weight regain.
Jebb says, “Some people have a biological vulnerability to weight gain and we are surrounded by energy-dense foods and cheap deals. Obesity is a chronic relapsing condition, and it may be necessary for people to follow a weight-loss program every few years to keep their weight down and manage their risk factors. It's not an ideal solution, but until we have a better option, we should celebrate and support people who make repeated efforts to manage their weight to improve their health.”