Dieting has long been championed as a means to achieve not only smaller bodies but also improved health. The pervasive message from the $75 billion U.S. weight loss industry suggests that adhering to the right diet is the key to sustained weight loss. However, the emergence of new weight loss drugs, such as Wegovy and Zepbound, has raised questions about the effectiveness of conventional dieting for the millions who have tried it. In a 2021 clinical trial of semaglutide, the active ingredient in Wegovy, participants experienced a weight loss of about 15 percent, contrasting significantly with those relying solely on diet and exercise, who saw only a 2 percent reduction.
Despite the rising popularity of weight loss medications, there remains a significant population for whom such drugs are not the preferred option. For those individuals, the question persists: Is old-fashioned dieting a viable solution?
We turned to experts to gain insights into what dieting can achieve and its limitations.
Can a diet help you lose weight?
In the short term, various diets appear to assist most individuals in shedding at least a modest amount of weight, whether it’s a low-fat, low-carbohydrate regimen, or straightforward calorie restriction, according to Dr. Ellen Schur, the director of the University of Washington Nutrition and Obesity Research Center.
However, individual outcomes can vary significantly. A 2018 clinical trial, involving 600 participants following either a low-fat or low-carb diet for a year, demonstrated an average weight loss of 5 to 6 percent of body weight. Nevertheless, around 15 percent of participants gained weight during the study, highlighting the diverse responses to different diet approaches.
Dr. Maria Collazo-Clavell, an endocrinologist at the Mayo Clinic, notes that it is common for individuals to experience a plateau in weight loss at approximately six to eight months, after which there is a risk of regaining lost weight. Research suggests that most people revert to their initial weight within four years.
Why doesn’t the weight stay off?
When individuals lose weight, the body responds by intensifying appetite and reducing the number of calories burned, explains Dr. Kevin Hall, a nutrition and metabolism scientist at the National Institutes of Health. For every two pounds lost, metabolism slows by approximately 25 calories per day, and appetite increases by about 95 calories per day. Thus, after losing 20 pounds, the body burns roughly 250 calories less each day while craving around 950 calories more.
Sustaining weight loss through dieting demands continued calorie restriction and resistance to a heightened appetite and slower metabolism. However, maintaining this regimen becomes “increasingly difficult,” remarks Dr. Schur.
The intense drive to consume more calories is linked to the brain’s perception that energy stores are depleting, constituting a potential threat to survival.
Are there health risks associated with dieting for weight loss?
Dieting often results in cycles of weight loss and regain, with some studies suggesting potential harm. Kendrin Sonneville, an associate professor of nutritional sciences at the University of Michigan School of Public Health, highlights research indicating associations between weight fluctuation and earlier death, cardiovascular disease, Type 2 diabetes, and depression. However, there is ongoing debate about the conclusiveness of this evidence, with some studies including individuals who lost and regained weight due to health issues rather than dieting.
Dr. Schur acknowledges the debate surrounding the potential harm of weight fluctuations but stresses that conclusive evidence is lacking.
Concerns also extend to the possibility of developing eating disorders as a result of dieting. Dr. Sonneville notes anecdotal evidence linking eating disorders to dieting, although clinical weight loss trials have not consistently supported this. More research is needed to fully understand how dieting affects individuals’ long-term relationships with food and their bodies.
In conclusion, while dieting may yield short-term weight loss, its long-term efficacy remains a subject of debate. The challenges of sustained calorie restriction and the body’s natural responses to weight loss pose hurdles for many individuals. Moreover, potential health risks and the impact on mental well-being warrant careful consideration when embarking on a weight loss journey through traditional dieting methods.