I recently got a call from my sister, Erica. Her question was, “do I have to lose weight to be healthy?” Erica, despite being the athlete of the family (and recently running a 10k as she’d like pointed out), has always struggled with her mental health, her body image, and her weight. In fact, excess fat is something my whole family has struggled with for as long as I can remember. Looking back, I can hardly remember a period of my childhood during which my father was not actively trying to lose weight. Weight loss itself was regularly a dinner table discussion for us. My sister and I would pose questions to our father like,  “How do we lose weight? What are the best diets? Will this detox make me skinny?, etc…” the only question missing from these dinner table discussions was, “should I lose weight?” or “is weight loss the best thing to focus on for my goals?” These questions were never even considerations. It was always just assumed that beginning a weight-loss intervention was the best thing for our health, social status, and performance goals, but is that true? Is weight loss always the best thing for those with excess fat? With the goal of answering this question, we will dive into the current research on the risks associated with obesity and excess fat, as well as some of the pitfalls of weight loss interventions.

Obesity is an Immense Global Burden

On the population level, excess fat is a major burden on the world. A study in 2009 by Finkelstein et al. found that the annual cost of obesity in the United States had risen to $147 billion in 2008.¹ This is in comparison to $214 billion for heart disease in 2017, $249 billion due to excessive alcohol consumption in 2015, $170 billion dollars due to cigarette smoking in 2014, and an estimated $174 billion due to cancer in 2020.² Further, in 2009, the WHO published a report that put obesity as the fifth leading global risk factor for death behind high blood pressure, tobacco use, high blood sugar, and physical inactivity.³ Since then, obesity rates have only continued to increase. In fact, in the United States, the Centers for Disease Control and Prevention estimated the prevalence of obesity, defined by a Body Mass Index (BMI) ≥ 30, to have increased from 35.7% in the 2009-2010 survey year to 42.4% in the 2017-2018 survey year.⁴ Similarly, the prevalence of severe obesity (BMI ≥ 40) increased from 6.3% to 9.2% in the same time period.⁴ This trend is expected to continue. Recently, in December of 2019, an article was published in the New England Journal of Medicine that estimated the prevalence of obesity in the United States to increase to approximately 50% by 2030.⁵

On top of being a leading risk factor for death, obesity is also a large contributor to chronic disease and disability. Obesity increases the risk for the development of high blood pressure, type II diabetes, osteoarthritis, high cholesterol, and depression, among others.⁶ It is such a major contributor to these chronic conditions that, for many of these, weight loss of 5-15% of body weight can result in disease remission.⁶ For that reason, weight loss interventions, including lifestyle, pharmacologic, and surgical types, are recommended in not only the prevention, but also in the treatment of these conditions.⁶

The Pitfalls of Weight-loss

Given the prevalence of obesity and its association with these aforementioned outcomes, it is easy to see how weight loss could be viewed and portrayed by many as a panacea of health. However, this portrayal fails to take into account the potential for harm in weight loss interventions, the difficulty with which weight loss is attained and retained, the small absolute increase in risk attributable to obesity (defined as BMI>30), and the ability to control risk through alternate means.

Potential for Harm

While the potential for benefit in a weight loss intervention is substantial, weight loss is not entirely risk free. The risk of weight loss for which we have the most robust data is the potential for weight cycling- a phenomenon whereby individuals who lose weight often regain that weight and then continuously cycle through periods of weight gain and weight loss, leading them to be worse off than when they started. In fact, this phenomenon has been associated with higher BMI, decreased glucose tolerance, lower self-esteem, and a higher prevalence of binge eating. However, results are mixed, probably due, in part, to the lack of a universal definition of what exactly constitutes weight cycling.⁷ Further, a reduction in weight regain (and, therefore, cycling) is seen in individuals undergoing long-term pharmacologic interventions and bariatric surgery.⁶

It is also important to note that obesity may have paradoxical protective effects in various conditions including in heart disease and type II diabetes such that obesity at the time of diagnosis of these conditions results in better prognosis even though obesity increases risk for their development.⁷ However, weight loss in these individuals after diagnosis, and especially, fat mass loss, are generally associated with a lowering of disease markers. For example, in the case of type II diabetes, it has been determined with a high level of confidence that weight loss to a targeted drop in A1C, a diabetes-specific disease marker, is beneficial⁶. However, this same review by the American Association of Clinical Endocrinologists (AACE), was unable to recommend weight loss for prevention of heart disease or extension of life in either those with or those without type II diabetes. That said, AACE adds the caveat that “the degree of weight loss achieved by bariatric surgery can reduce mortality.”⁶ This suggests that the lack of benefit seen from weight loss in certain studies of these populations is due to the small magnitude of weight loss, and that larger amounts of weight loss may extend life.

Further, there is also a subset of obesity for which weight loss may provide no benefit. This has been termed metabolically healthy obesity.8 According to Brown and Kuk, these individuals are “typically defined as having excess body fat, but are insulin sensitive, normotensive, have a favorable lipid profile and have less visceral fat than the typical individual with obesity‐related comorbidities.” These individuals are generally highly physically active, and eat better diets in comparison to similar weight individuals.⁷ Trials attempting to study this subset of individuals have ended in mixed results, some showing benefit to weight loss, while others show no benefit. This stark contrast in findings may be due to differences in defining this subpopulation, with some studies allowing individuals with one of the metabolic abnormalities listed above. Regardless, this group of individuals appears to be a very small subset of those with obesity, with current estimates putting the prevalence at about 3-6% of obese individuals, although some experts question the existence of this group at all. ⁷

Lastly, it is important to address potential effects of weight loss interventions on disordered eating and mental health. Many of those who struggle with eating disorders and disordered eating engage in dieting behaviors prior to diagnosis, and dieting behavior is considered a risk factor for certain eating disorders.⁸ However, according to Jones et. al., there is currently not enough evidence to assess the impact of weight loss interventions on binge eating, emotional eating, or body image.⁹ This means, that as the evidence stands right now, we can say that those with eating disorders often engage in dieting behaviors, but we cannot say that dieting behaviors lead to eating disorders. In fact, in the same study, Jones et. al. found an overall beneficial effect of weight loss on depression, overall self-efficacy, and mental health-related quality of life while finding no evidence that weight loss interventions had a negative effect on mental health. ⁹

Difficulty in Attaining and Retaining Weight Loss

While the above effects are important critiques of weight loss interventions, the loudest critique of these interventions is the characterization of body composition as a non-modifiable risk factor. Proponents of this critique cite the low average amount of weight lost in various interventions, and the high rate of weight regain before the completion of 12 months.¹⁰ That said, in a recent lifestyle intervention involving non-clinical staff support, 30% of participants in the intervention group achieved a clinically significant weight loss (> 5% bodyweight) at 12 months.¹¹ Further, this argument neglects to mention the stunning average weight loss of those undergoing pharmacologic (10-15% bodyweight)⁶ or surgical weight loss interventions (up to 35% body weight)⁷ for whom weight loss is generally maintained as long as the medicine or surgical change is present.⁶ To draw an analogy to another disorder, many with high blood pressure struggle to control it with dietary intervention alone; however, with adequate support, most can achieve clinically significant reductions.¹² The difficulty with which controlled blood pressure is attained does not stop us from trying to control it. Like reductions in blood pressure, weight loss is absolutely possible and sustainable even if it can be difficult and require medical support. 

Absolute Risk Increase

Also of note in any conversation regarding the risks and benefits of weight loss is the increase in the risk of death due to obesity. According to data published by Adams et al., in a population of men aged 50 through 71 at enrollment in 1995-1996, the absolute risk increase in all-cause mortality attributable to a BMI ≥ 30 as compared to a BMI between 18.5 and 24.9 was only 1.62%. However, there is a positive correlation between BMI and mortality in obesity, such that a BMI ≥ 40 yields a risk increase of over 9%.¹³  So, overall, obesity does increase our risk of dying; however, even within obese populations, risk exists on a spectrum. Generally, being younger, male, and having greater fat mass increases the additional risk of death due to obesity. This additional risk should be a major consideration in any decision to undergo a weight-loss intervention.

Alternate Means

Lastly, the AACE clinical guidelines on obesity state that weight loss should be used as a means to treat weight-related complications.⁶ In other words, we don’t want those with obesity to lose weight for sake of the weight loss, but rather, for the associated benefit this weight loss has on comorbid conditions. If weight loss is not our primary goal, but rather improvement in weight-related issues, then we can choose to focus on other ways to improve these issues. For example, type II diabetes is tightly linked to obesity, but it is also modified by physical activity, diet, and sleep, among others.¹⁴ If we can achieve acceptable control of the diabetes through measures unrelated to weight loss, then the loss of weight, in itself, may not be necessary. However, it is important to note that those with greater amounts of body fat initially stand to gain more from a weight-loss intervention with respect to these complications⁶, and weight-loss interventions should be weighted more heavily as a treatment option in these individuals.

Can we Be Healthy without Weight Loss?

So, can we be healthy without weight loss? Health, in many ways, is a somewhat nebulous term. While everyone knows intuitively what health is, the actual definition of health is hard to nail down. For the purposes of this discussion, though, we will utilize Huber et al.’s definition of health as “the ability to adapt and to self-manage.”¹⁵ Based on this definition, the answer is a resounding yes. Many individuals with obesity choose to adapt and self-manage by focusing not on weight loss, but on physical activity, the non-energetic aspects of their diets, their sleep patterns, and their consumption of alcohol, tobacco, and other substances. Focusing on these aspects of their health allows them to remain highly adaptable, and to reduce their risk of death and morbidity associated with their condition. Further, this definition correctly takes into account the fact that those with higher socioeconomic status will be more likely to be healthy at any given BMI given their greater ability to adapt to and self-manage their disease. However, regardless of socioeconomic status or any other resiliency factor, there is a point at which the ability of those with obesity to self-manage and to adapt is restricted by their fat mass, and, in these cases, it is necessary for a weight loss intervention to be employed with the help of medical professionals. In this case it is recommended that weight loss be used as a method to return this individual to a point where self-managing is possible, improving the complications associated with the weight, rather than focusing on the weight itself. 

So, while it is possible to both have obesity and be healthy, weight-loss is beneficial for almost all those carrying excess fat. However, weight loss is difficult, may be more beneficial for some than others, and improvement in markers of health can be attained through other means. Knowing this, we recognize that many people may choose to direct their attention elsewhere in the maintenance of their health. While we think this is a good option for some, we suggest weight loss for the majority of those with excess fat, noting that there are many methods by which weight loss can be made easier, including through medication and surgery.

References

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