Combating Obesity: A Look Into The Future

The rising prevalence of obesity represents an important public health concern and is quickly becoming a major global health and economic burden. Obesity currently affects around 40% of adults and 20% of youths in the United States.1 Obesity is a condition where excess adipose or fat tissue accumulates in the body, so much so that it has numerous adverse effects on a person’s overall health, including placing individuals at risk for chronic diseases such as cancer, cardiovascular disease, and diabetes. It is defined as having a body mass index (BMI) of ≥30 kg/m².2

Classification and Causes
Currently, any person with a BMI ≥30 is considered obese, and a BMI of over 40 is considered morbidly obese. However, these classifications are not always accurate: bodybuilders often have a very high BMI and are technically obese, although they do not suffer from the same health risks. Other factors like body fat percentage, waist-to-hip ratio, and total cardiovascular risk factors can be calculated for a more comprehensive diagnosis of obesity.3 Fat accumulation depends on several factors, including diet and exercise. Individuals who maintain a caloric limit on their food intake and exercise regularly have significantly lower rates of obesity than individuals with a larger caloric intake and less exercise.4 Certain genetic factors, while rare, also have been linked to obesity, including several syndromes like Prader-Willi Syndrome, Cushing’s Syndrome, Bardet-Biehl Syndrome, and Cohen Syndrome. Individuals with these genetic conditions are often at high risk of obesity and related conditions from a young age.5

Emerging Causes of Obesity
Obesity in adults and children has been attributed to a number of factors, including physical inactivity, nutritional intake, and maternal BMI. An emerging potential cause of pediatric obesity are disruptions to the gut microbiome, or the microorganisms that are natural to and live in our digestive systems. Exposure to infection and subsequent antibiotic use may be associated with an increased risk of obesity in childhood.6 Some research shows that antibiotic use is associated with higher weight gain, while other studies have shown that an increased number of infections is associated with an increased risk of obesity.7 Because this is a fairly new area of research, there remain many questions about the relationships among infection, antibiotic use, and obesity. Untangling these relationships could support new kinds of efforts to prevent childhood obesity.

Novel Obesity Interventions
In addition to research into new causes of obesity, researchers are also investigating new kinds of solutions. Because obesity is associated with unbalanced gut bacteria, one such approach uses probiotics to combat obesity. Recent studies have found that the administration of probiotics resulted in a larger decrease in body weight and fat percentage compared to the placebo. There are several potential mechanisms for how probiotics can aid in fat loss. By-products from fermentation in the gut may decrease appetite and increase feelings of fullness. Gut bacteria could also change an individual’s tastes and dietary preferences.8 While the mechanisms and effects of probiotics on obesity are still being studied, probiotics seem to have a valuable role in the treatment and prevention of obesity.

Despite the clear impact medical and surgical treatments can have on obesity, there is still a great deal of variability in individual responses to these treatments. Previously, these individual variations were attributed to psychosocial, cultural, and economic factors. However, more recent evidence supports a larger impact of genetic differences on these variations. A better understanding of the genetics behind obesity has enabled the development of more novel and precise approaches, part of the precision medicine model.9 In the context of obesity prevention and treatment, precision medicine seeks to develop a standardized set of diagnostic tools that includes biosamples for genetic analysis; patient-reported measures; wearable devices that objectively monitor stress, physical activity, and sleep; and behavioral tasks. Doctors could then use these tools to guide therapeutic recommendations.10 These novel methods hold the potential to better align diagnoses with the most effective treatment for a particular patient at a given time. When combined with efforts to improve population health, precision medicine has the potential to substantially reduce the burden of illness and disability due to obesity.

References
  1. Hales CM, Carroll MD, Fryar CD, Ogden CL. Prevalence of Obesity Among Adults and Youth: United States, 2015–2016. Hyattsville, MD. US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics 2017. 288:1-8.
  2. World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Geneva, Switzerland. World Health Organization 2000.
  3. Williamson DA, Newton RL, Walden HM. Obesity. In: Formulation and Treatment in Clinical Health Psychology. New York, NY: Routledge; 2006:42-59.
  4. Fock KM, Khoo J. Diet and exercise in management of obesity and overweight. Journal of Gastroenterology and Hepatology. 2013;28:59-63. doi:10.1111/jgh.12407.
  5. Farooqi IS, O’Rahilly S. Genetics of Obesity in Humans. Endocrine Reviews. 2006;27(7):710-718. doi:10.1210/er.2006-0040.
  6. Forrest, Christopher B., et al. “Antibiotics, Infections, and Childhood Obesity.” The Lancet. Diabetes & Endocrinology, vol. 5, no. 1, Jan. 2017, pp. 2–3. PubMed Central, doi:10.1016/S2213-8587(16)30314-X
  7. Li, De-Kun, et al. “Infection and Antibiotic Use in Infancy and Risk of Childhood Obesity: A Longitudinal Birth Cohort Study.” The Lancet. Diabetes & Endocrinology, vol. 5, no. 1, Jan. 2017, pp. 18–25. PubMed, doi:10.1016/S2213-8587(16)30281-9.
  8. Borgeraas H., et al. Effects of probiotics on body weight, body mass index, fat mass and fat percentage in subjects with overweight or obesity: a systematic review and meta-analysis of randomized clinical trials. Obesity Reviews. 2018; 2(19):219-232. https://doi.org/10.1111/obr.12626
  9. National Research Council (US) Committee on a Framework for Developing a New Taxonomy of Disease. Toward precision medicine: building a knowledge network for biomedical research and a new taxonomy of disease. National Academies Press 2011.
  10. Yanovski SZ and Yanovski JA. Viewpoint: Toward Precision Approaches for the Prevention and Treatment of Obesity. JAMA 2018. 3193: 223-224.

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