Robert F. Kushner

Overweight and obesity is the most common medical problem seen in primary care practice, affecting over 60% of adults and 15% of adolescents. ^{1 , 2} Obesity, along with diet and physical inactivity, is estimated to be responsible for approximately 400,000 preventable deaths per year and is expected to soon rival cigarette smoking as the most important public health concern. ³ The etiology of obesity is multifactorial, brought about by an interaction between predisposing genetic and metabolic factors and a rapidly changing environment. Interactive influences include social, behavioral, physiological, metabolic, cellular, and molecular factors. The most exciting breakthroughs in obesity research over the past decade have come from our understanding of the metabolic processes that control body-weight regulation. It appears that multiple feedback loops exist between the central and autonomic nervous systems, the endocrine glands, and adipose tissue, which operate to adjust hunger, satiety, and energy expenditure. Weight maintenance is now considered to be governed by a combination of short-term mechanisms originating in the gastrointestinal (GI) tract and longer-term processes, which monitor total adipose mass involving feedback to the central nervous system (CNS). ⁴ Signals that provide short-term information about hunger and satiety include gut hormones, such as cholecystokinin (CCK), ghrelin, and peptide YY_3-36 (PYY), and signals from the vagus afferent neurons within the GI tract that respond to mechanical deformation, macronutrients, pH, tonicity, and hormones. ⁵ Whereas ghrelin stimulates food intake, PYY produces satiety. Several recent reviews on the metabolic regulation of body weight and appetite control have been published. ^6–8

Objective: Obesity is a significant public health problem that is affecting people and their pets. The human‐companion animal bond and the role of pets in providing social support provides a rationale framework for studying the effectiveness of a combined people and pets (PP) exercising together (PPET) weight loss program.Research Methods and Procedures: Thirty‐six pairs of overweight or obese people with an obese pet (PP) and 56 overweight or obese people only (PO) participated in a 1‐year prospective controlled weight loss study. In a group format, people received dietary and physical activity counseling, and dogs were fed a calorie‐controlled prescription diet. Physical activity was recorded using the physical activity recall questionnaire.Results: Completion rates at 1 year were 61% for the PP group and 58% for the PO group. Mean weight losses at 12 months using last observation carried forward were 4.7% (PP) and 5.2% (PO). Mean weight loss among the dogs was 15%. Time spent in physical activity increased in both groups to 3.9 (PP) and 3.5 (PO) h/wk. Two‐thirds of total physical activity in the PP group was spent with the dogs.Discussion: The PPET study is the first program to demonstrate the effectiveness of a combined PP weight loss program. This fresh approach to the dual obesity epidemic builds on the human‐companion animal bond. Consideration of social support for weight loss of family members, friends, and coworkers should be extended to include pets.

Purpose of review Bariatric surgery is associated with the development of several micronutrient deficiencies that are predictable, preventable and treatable based on the surgically altered anatomy and imposed dietary changes. With an increasing number of severely obese patients undergoing bariatric surgery, clinicians need to become familiar with the surgical procedures and associated nutritional deficiencies. This article will review the pathophysiology, clinical presentation, screening tests, and treatment for selected micronutrient deficiencies. Recent findings The three restrictive malabsorptive procedures – Roux-en-Y gastric bypass, biliopancreatic diversion and biliopancreatic diversion with duodenal switch – pose a greater risk for micronutrient malabsorption and deficiency than the purely restrictive laparoscopic adjustable silicone gastric banding. Although other micronutrients have been reported, the metabolic and clinical deficiencies of two minerals (iron and calcium) and four vitamins (thiamine, folate, vitamin B₁₂ and vitamin D) have been most frequently described in the literature. Subclinical and clinical presentation of deficiencies can occur from weeks to years following the surgical procedures. Metabolic bone disease is the most concerning long-term nutritional complication. Summary All patients undergoing restrictive–malabsorptive procedures must be evaluated for development of micronutrient deficiencies. With careful monitoring and adequate supplementation, these deficiencies are largely avoidable and treatable.

Low‐carbohydrate diets are based on an alternative theory of obesity where dietary carbohydrate, particularly unprocessed sugars, causes hyperinsulinemia, leading to insulin resistance, obesity, and cardiovascular disease. In this model, carbohydrate is viewed as a “metabolic poison” and therefore is limited in the diet. This article systematically reviews and refutes the 6 major physiologic claims made by proponents of low‐carbohydrate diets. Any benefits or advantages resulting from these diets must therefore be derived from factors other than those stated by the alternative theory.