This study just confirmed what we all know about weight loss

You probably already know this. In fact, you might have experienced it yourself. And, it’s one of the most frustrating things about trying to lose weight. 

New research out of the University of Nottingham in the United Kingdom found that losing weight over the long term is extremely difficult. So difficult, in fact, that most people are not able to do it. 

Sustained weight loss is extremely difficult

The U.K. study tracked over 260,000 people over more than 10 years. Researchers focused on people over the age of 18 and looked at anonymized medical records to track obesity rates. 

“The majority of adults who are overweight or obese retain their degree of overweight or obesity over the long term,” the report concluded. “These findings highlight the high cardiovascular toll exacted by continuing failure to tackle obesity.”

The Nottingham study confirms what other studies have shown in the past. For instance, this International Journal of Obesity study found that while diet and exercise results in meaningful weight loss initially, sustained weight loss over the long term is far from a guarantee. 

“It seems that even losing weight with [diet and exercise], most obese individuals do not maintain the loss for long periods.” This study added that there are no widely accepted guidelines to promote behavior and lifestyle changes for permanent weight loss. 

There is little evidence to support the notion that diets lead to lasting weight loss. 

Why diets fail

“Dieting increases stress sensitivity, and stress makes us seek out rewarding things like high-fat, high-calorie “comfort” foods,” writes Science Mag. Many diets fail because they don’t fundamentally change how our bodies process the food that we take in. And, our innate ability to become accustomed to dietary changes makes diets less effective over time. 

Stress may be a significant contributing factor, said University of Pennsylvania neuroscientist Tracy Bale. “Stress causes the body to release the hormone cortisol, which fuels the blood with energy in the form of sugar, enabling us to flee from potential dangers.” Over time, Science Mag added, stress-related boosts to our cortisol levels can lead to an increase in our appetite and, as a result, weight gain. 

Along with a team of researchers, Bale put her hypothesis that diet-induced stress leads to weight gain to the test using mice. Researchers cut the food intake of mice by 25% for three weeks, causing the mice to shed 10 to 15% of their body weight. Then, the mice were subjected to mild forms of stress like loud noises. 

As a result of stress, the slightly skinnier mice had higher levels of cortisol in their blood. After being allowed to return to their pre-study weight, the mice were again subject to stress tests and found that cortisol levels were still higher, long after they stopped dieting. 

The study reveals that “ex-dieters remained more sensitive to stress than non-dieters and were more likely to eat large amounts of high-fat mouse chow when under pressure.”

“Dieting is tough because your brain is working against you,” Bale says. 

She believes that learning how to cope with stress in healthier ways could be the answer to longer-term, sustained weight loss that diets have been unable to provide.