In a culture that tells you that something is wrong with your body and needs to be fixed, diets and “lifestyle plans” can feel very tempting. But what does science really say about dieting to lose weight? Is it effective? Is it sustainable? Can it improve our overall health? We’ll dive into all of this and more in today’s article.
Content warning: Stigmatizing language referring to weight and weight loss numbers used in the study
With the start of a new year, the message of “new me” is prevalent, and with it comes the onslaught of New Year’s resolutions and full-scale marketing efforts from catering companies.
I’ve heard that January is called “National Diet Month” because this time of year there are so many diet/health/”lifestyle” companies (or whatever they call themselves nowadays) and many people are especially susceptible to their marketing News heading into the new year.
$77B What the diet industry doesn’t tell you is that all the research shows that diets don’t work in the long term. Because their bottom line relies on repeat customers—the same people trying their plans over and over again.
It’s helpful to know what’s in the scientific literature about dieting and weight loss, but more important than the research (IMO) is your lived experience. Has dieting worked for you in the past? How long have they been working? Did you end up gaining the weight back? Do you feel your diet/lifestyle plan is sustainable? Why or why not? You know your body best.
Dieting and Weight Loss Research
Mann et al. 2007 review of the scientific literature on dieting and weight loss. Only 14 studies were found that looked at weight loss outcomes after 4 years or longer. This means that all other literature on diet and weight loss has a very short-term follow-up (usually one year). These study designs benefit the diet industry because we know that diets work in the short term, but after a few to several years, most people gain the weight back.
The review found that in the studies they looked at, participants lost between 10 and 65 pounds. At the time of tracking, most of the weight had been regained. Results range from a net loss of 15 pounds to a net gain of 8 pounds compared to where you started.
30-64% of participants ended up at or above their pre-diet weight.
Only 9% of participants ended up with a body mass index below 35. Participants who lost more than 15% of their body weight actually doubled their risk of death.
A 2018 overall review of meta-analyses of weight loss interventions found that “across the many available interventions, there is no high-quality evidence to recommend specific non-surgical or non-pharmacological interventions to treat ‘obesity.'” That is to say. , we do not have sufficient evidence to recommend diet or lifestyle intervention for weight loss.
Naturalistic studies (observing people in natural settings and recording behavior) have concluded that dieting is actually a predictor of weight gain. So not only does dieting not work, but it can lead to weight gain. Several meta-analyses and comprehensive reviews report the same results—lifestyle interventions can actually lead to weight gain, especially over long-term follow-up.
Other reviews suggest that weight loss of 3-5% over several years is possible if all aspects of treatment are maintained. More specifically, for a 200-pound person, this means a weight loss of 6-10 pounds. The health benefits of this modest weight loss are unclear. Most people want to lose 30%, not 3-5%.
Are health risks related to weight due to weight cycling?
Research shows that weight cycling (weight loss, weight gain, weight loss and repeat) is a risk factor for diabetes, dyslipidemia, poor self-perception, insulin resistance, hypertension and visceral fat.
A 15-year study showed that the highest mortality rates were among people who lost weight, not those who gained weight or kept their weight stable. This study and others suggest that weight cycling may be worse for your health than maintaining/maintaining a higher weight.
What if the weight-related health risks we see are actually caused by repeated attempts to lose weight and the stress it puts on the body rather than the body’s actual size?
We know that health-promoting behaviors (exercise, eating more fruits and vegetables, getting enough sleep) can reduce the risk of death regardless of changes in weight. Well, that’s right. You can improve your health indicators without losing weight.
It’s also important to consider how weight stigma or anti-fat bias plays a role in the data we see between higher body weight and poorer health outcomes. The literature states that “prejudice may undermine people’s efforts to pursue a healthy lifestyle through negative emotional distress and unhealthy dietary patterns.”
It’s also worth noting that all studies on weight and health risks are correlational. One thing you always get stressed out about when you’re learning how to read and analyze research is that “correlation does not equal causation.” We cannot say that weight causes chronic disease—there is no literature to support this.
If you looked at all the data on smoking/tobacco use and lung cancer and found a correlation between people with yellow teeth and lung cancer, you would never say the yellow teeth caused the cancer, you would say it was a side effect of smoking. Yellowing teeth is not a behavior.
Just because weight is associated with chronic disease doesn’t mean it’s the cause. Weight is not a behavior either.
“Overweight” BMI has lowest risk of death
We have always believed that being overweight is bad for your health.What we don’t hear is research shows Being “overweight” has a lower risk of death than being “normal weight”. A BMI of 30-34.9, known in the medical field as “Grade 1 obesity,” has also been shown to carry no greater risk of death than “normal” weight.
Why is no one talking about the protective effects of being overweight? Because that doesn’t bode well for all the pharmaceutical companies selling weight-loss drugs and the diet industry selling lifestyle plans.
Anyway, BMI is complete bullshit, but I could write another entire blog post on the subject, so I’ll save that for another time.
refer to:
Solmi, M., Köhler, CA, Stubbs, B., Koyanagi, A., Bortolato, B., Monaco, F.…, and Carvalho, AF (2018). Environmental risk factors and nonpharmacological and nonsurgical interventions for obesity: a general review of meta-analyses of cohort studies and randomized controlled trials. European Journal of Clinical Investigation, 48(12), e12982.
Lissner, L., Odell, PM, D’Agostino, RB, Stokes, J., Kreger, BE, Belanger, AJ, & Brownell, KD (1991). Variability in weight and health outcomes in the Framingham population. New England Journal of Medicine, Chapter 324(26), 1839–1844. https://doi.org/10.1056/NEJM199106273242602
Tolvanen, L., Ghilotti, F., Adami, H.-O., Ye, W., Bonn, SE, Bellocco, R., & Lagerros, YT (2023). Prospective study of weight loss and all-cause, cardiovascular, and cancer mortality. scientific report, 13(1), 5669. https://doi.org/10.1038/s41598-023-32977-8
Mulligan, AA, Lentjes, MAH, Luben, RN, Wareham, NJ, & Khaw, KT (2018). Weight change and 15-year mortality: results from the European Prospective Investigation into Cancer-Norfolk (EPIC-Norfolk) cohort study. european journal of epidemiology, 33(1), 37–53. https://doi.org/10.1007/s10654-017-0343-y
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