Bruce M. Wolfe

Global economic development has been associated with an increased prevalence of obesity and related health problems. Increased caloric intake and reduced energy expenditure are both cited as development-related contributors to the obesity crisis, but their relative importance remains unresolved. Here, we examine energy expenditure and two measures of obesity (body fat percentage and body mass index, BMI) for 4,213 adults from 34 populations across six continents and a wide range of lifestyles and economies, including hunter-gatherer, pastoralist, farming, and industrialized populations. Economic development was positively associated with greater body mass, BMI, and body fat, but also with greater total, basal, and activity energy expenditure. Body size–adjusted total and basal energy expenditures both decreased approximately 6 to 11% with increasing economic development, but were highly variable among populations and did not correspond closely with lifestyle. Body size–adjusted total energy expenditure was negatively, but weakly, associated with measures of obesity, accounting for roughly one-tenth of the elevated body fat percentage and BMI associated with economic development. In contrast, estimated energy intake was greater in economically developed populations, and in populations with available data (n = 25), the percentage of ultraprocessed food in the diet was associated with body fat percentage, suggesting that dietary intake plays a far greater role than reduced energy expenditure in obesity related to economic development.

Objective: This observational study investigated metabolomic changes in individuals with type 2 diabetes (T2D) after weight loss. We hypothesized that metabolite changes associated with T2D‐relevant phenotypes are signatures of improved health.Methods: Fasting plasma samples from individuals undergoing bariatric surgery (n = 71 Roux‐en‐Y gastric bypass [RYGB], n = 22 gastric banding), lifestyle intervention (n = 66), or usual care (n = 14) were profiled for 139 metabolites before and 2 years after weight loss. Principal component analysis grouped correlated metabolites into factors. Association of preintervention metabolites was tested with preintervention clinical features and changes in T2D markers. Association between change in metabolites/metabolite factors and change in T2D remission markers, homeostasis model assessment of β‐cell function, homeostasis model assessment of insulin resistance, and glycated hemoglobin (HbA1c) was assessed.Results: Branched‐chain amino acids (BCAAs) were associated with preintervention adiposity. Changes in BCAAs (valine, leucine/isoleucine) and branched‐chain ketoacids were positively associated with change in HbA1c (false discovery rate q value ≤ 0.001) that persisted after adjustment for percentage weight change and RYGB (p ≤ 0.02). In analyses stratified by RYGB or other weight loss method, some metabolites showed association with non‐RYGB weight loss.Conclusions: This study confirmed known metabolite associations with obesity/T2D and showed an association of BCAAs with HbA1c change after weight loss, independent of the method or magnitude of weight loss. image

Cancer is a principal cause of morbidity and mortality for persons living with obesity. Obesity increases the risk of developing at least 13 types of cancer. Meta-analyses of cohort studies observe that bariatric surgery is independently associated with a 44% lower relative risk of invasive cancer than non-surgical obesity care. Breast and endometrial cancers are associated with bariatric surgery's largest relative risk reductions. Emerging data also indicate that bariatric surgery may be associated with a lower risk of death from cancer. The anti-cancer mechanisms of bariatric surgery remain incompletely understood; hypothesized mechanisms relate to correcting the metabolic dysfunction caused by excess adipose tissue, including insulin resistance and insulin-like growth factors, inflammation, adipokine and lipid synthesis, oxidative stress, and sex steroid hormones. There exist tremendous research opportunities to advance our understanding of how bariatric surgery can be utilized as a modality for cancer prevention and control. Modern bariatric surgical procedures have strong evidence of safety and efficacy in reducing body weight and improving metabolic health. Patients and their physicians should engage in a shared decision-making conversation about surgical risk and potential benefits, including cancer risk reduction, compared with non-surgical care for obesity.

Breast cancer is the most common and second deadliest malignancy in women. With rising obesity rates and building evidence for a strong association with obesity, the incidence of breast cancer can be expected to increase. Weight loss reduces breast cancer risk, the mechanisms of which are still poorly understood. As an effective therapy for obesity, bariatric surgery may be a powerful tool in breast cancer prevention and treatment. This review details the potential physiologic mechanisms that may underlie this association, as well as recently published studies that reinforce the link between bariatric surgery and a reduction in incident breast cancer. The use of bariatric surgery as an adjunct therapy in endometrial cancer also raises the potential for similar use in select breast cancer patients. Despite the expanding potential applications of bariatric surgery in this field, publications to date have been strictly observational, highlighting a need for future clinical trials.

Objective: This study aimed to examine whether pregnancy following bariatric surgery affects long‐term maternal weight change and offspring birth weight.Methods: Using data from the Longitudinal Assessment of Bariatric Surgery (LABS)‐2 study, linear regression was used to evaluate percent change in total body weight over a 5‐year follow‐up period among reproductive‐aged women who underwent Roux‐en‐Y gastric bypass or laparoscopic adjustable gastric banding as well as evaluate the association of bariatric procedure type and offspring birth weight.Results: Of 727 women with preoperative age of 36.1 (6.3) years (mean [SD]) and BMI of 46.9 (7.0) kg/m², 80 (11%) reported at least one pregnancy. After adjusting for covariates, percent change in total body weight was not significantly different between women who became pregnant and those who did not during a 5‐year follow‐up period (β = 2.02; 95% CI: −1.03 to 5.07; P = 0.19). Additionally, mean birth weight was not significantly different between mothers who underwent Roux‐en‐Y gastric bypass versus laparoscopic adjustable gastric banding (P = 0.99).Conclusions: Postoperative pregnancy did not diminish long‐term weight loss in women in the LABS‐2 study. The finding of comparable weight loss is relevant for providers counseling women of reproductive age on weight‐loss expectations and family planning following bariatric surgery.

Objective: This study sought to determine improvements in mental and physical health–related quality of life (HRQOL) following bariatric surgery in Medicaid and commercially insured patients.Methods: Using data from the Longitudinal Assessment of Bariatric Surgery, an observational cohort study of adults undergoing bariatric surgery (2006‐2009), changes in Short Form 36 mental component summary (MCS) and physical component summary (PCS) scores were examined in 1,529 patients who underwent Roux‐en‐Y gastric bypass, laparoscopic adjustable band, or sleeve gastrectomy and were followed for 5 years. Piecewise linear mixed‐effects models estimated MCS and PCS scores as a function of insurance group (Medicaid, N = 177; commercial, N = 1,352) from 0 to 1 year and from 1 to 5 years after surgery, with interactions between insurance group and surgery type.Results: Patients with Medicaid had lower PCS and MCS scores at baseline. At 1 year after surgery, patients with Medicaid and commercial insurance experienced similar improvement in PCS scores (commercial‐Medicaid difference in PCS change [95% CI]: Roux‐en‐Y gastric bypass, 1.5 [−0.2, 3.3]; laparoscopic adjustable band, 1.9 [−2.2, 6.0]; sleeve gastrectomy, 6.4 [0.0, 12.8]). One‐year MCS score improvement was minimal and similar between insurance groups. In years 1 to 5, PCS and MCS scores were stable in all groups.Conclusions: Both insurance groups experienced improvements in physical HRQOL and minimal changes in mental HRQOL.

Objective: This study sought to examine weight change, postoperative adverse events, and related outcomes of interest among age‐qualified (AQ) and disability‐qualified (DQ) Medicare recipients compared with non‐Medicare (NM) patients undergoing an initial bariatric procedure.Methods: The Longitudinal Assessment of Bariatric Surgery (LABS‐2) is an observational cohort study of 2,458 adults who underwent Roux‐en‐Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB) bariatric surgery. Weight, percentage body fat, functional status, and comorbidities, as well as postoperative adverse events, were assessed at baseline and annually for 5 years. The 1,943 participants who reported insurance type were categorized into the following groups: AQ, DQ, or NM.Results: The median preoperative BMI ranged from 45 to 48 kg/m² across groups. For RYGB, 5‐year BMI loss was approximately 30% for all groups, and for LAGB, BMI loss was 12% to 15%. Diabetes remission after 5 years was also similar across groups within procedure types (RYGB: 33%‐40%; LAGB: 13%‐19%). The frequency of adverse events after RYGB ranged from 4.1% for NM participants to 6.7% for DQ participants. After LAGB, there were no adverse events for the AQ group, whereas 3% of DQ participants and 1.8% of NM participants had at least one adverse event.Conclusions: Medicare participants experienced substantial BMI loss and diabetes remission, with a frequency of adverse events similar to that of NM participants.