95% is a number that gets thrown around when talking about the percentage of people who lose weight through dieting and are able to maintain that loss for over five years. There aren’t many studies that actually follow for that long, so that number is not exact. Those that follow for two years find that 1/3 to 2/3 of participants have gained the weight back, which is pretty grim. Imagine someone selling an iOS app that only worked for a random 40 out of every 100 iOS users, and no one can figure out why or how to make it work for everyone. No one would buy it. But we keep buying into “eating less” as a solution for everyone. The studies that back up the numbers and results I mentioned are below.
Dieting Does Not Work, UCLA Researchers Report
“People on diets typically lose 5 to 10 percent of their starting weight in the first six months, the researchers found. However, at least one-third to two-thirds of people on diets regain more weight than they lost within four or five years, and the true number may well be significantly higher, they said.”
Widespread misconceptions about obesity
“Approximately two-thirds of people who lose weight will regain it within 1 year, and almost all of them will regain it within 5 years.(11) Although dieting (ie, caloric restriction) to lose weight is a difficult task, the maintenance of lost weight requires the patient to deploy even greater efforts. Rather than a simple lack of willpower, the relapse of most individuals to their previous weight after otherwise successful weight loss is largely driven by the coordinated actions of metabolic, neuroendocrine, autonomic, and behavioural changes that oppose the maintenance of reduced body weight.(12)”
“We drew a sample of individuals aged 20 years and older from the United Kingdom’s Clinical Practice Research Datalink from 2004 to 2014. We analyzed data for 76 704 obese men and 99 791 obese women…We estimated the probability of attaining normal weight or 5% reduction in body weight.
Results. During a maximum of 9 years’ follow-up, 1283 men and 2245 women attained normal body weight. In simple obesity (body mass index = 30.0–34.9 kg/m2), the annual probability of attaining normal weight was 1 in 210 for men and 1 in 124 for women, increasing to 1 in 1290 for men and 1 in 677 for women with morbid obesity (body mass index = 40.0–44.9 kg/m2). The annual probability of achieving a 5% weight reduction was 1 in 8 for men and 1 in 7 for women with morbid obesity.
Conclusions. The probability of attaining normal weight or maintaining weight loss is low.”
Low Calorie Dieting Increases Cortisol
“Prior research has demonstrated that dieting, or the restriction of caloric intake, does not lead to long-term weight loss. This study tested the hypothesis that dieting is ineffective because it increases chronic psychological stress and cortisol production — two factors that are known to cause weight gain.
Results. Restricting calories increased the total output of cortisol, and monitoring calories increased perceived stress.
Conclusions. Dieting may be deleterious to psychological well-being and biological functioning, and changes in clinical recommendations may be in order.”
I’ve collected more studies concerning obesity, exercise, and nutrition at FatScience.
