Obesity: Understanding and Achieving a Healthy Weight

Abstract

Increased body weight, expressed in the body mass index [BW (kg)/Ht (m)²], is one of the most widely used methods to assess the degree of overweight or obesity. Using this measure, the prevalence of obesity has been rising steadily as the epidemic of obesity has spread over the past 40 years (Lancet 388:759–601, 2016). Although obesity results from an imbalance between energy intake and expenditure, it is the connection between these two components of the first law of thermodynamics that can provide the clues about how we should understand, prevent, and treat this problem (Lancet 388:759–601, 2016). While nutrition is, of course, the ultimate “source” of a positive energy balance, many other factors impinge on whether an individual develops obesity.

The pathology of obesity can best be understood as an enlargement of fat cells, and in some individuals an increased number of fat cells (A guide to obesity and the metabolic syndrome, Boca Raton, 2011; Endocrinol Metab 89:2583–2589, 2004). These enlarged fat cells release less adiponectin as well as more fatty acids and a variety of cytokines, including leptin, and tumor necrosis factor-a that can provide a basis for understanding how obesity produces insulin resistance and changes in the inflammatory, thrombotic, and coagulation systems.

There is a large industry offering various forms of treatment. Although we can treat obesity with some success, we rarely cure it, and a plateau in body weight during treatment with subsequent relapse when treatment is terminated is the common experience. Surgical intervention with gastric bypass, sleeve gastrectomy, or gastric banding is the most effective treatment but at an increased risk of mortality and with substantial morbidity. There are five pharmacologic agents currently approved for long-term use but they produce only modest weight loss.

Let us start with the premise that all of us want to have a healthy weight. Interest in obesity has taken a sharp upturn in recent years as its prevalence has increased. Obesity can be viewed as a chronic, stigmatized, neurochemical disease (Int J Obes Relat Metab Disord 28:34–84, 2004). In this context, the goal is to return weight to a healthy level and to remove the stigma associated with the use of the word “obesity.” To consider it in the context of a neurochemical derangement has the advantage of focusing on the underlying mechanisms that produce the distortion in energy balance resulting in an unhealthy state (Int J Obes Relat Metab Disord 28:34–84, 2004).