Mindful eating for weight loss in women with obesity: a randomised controlled trial.

Mindful eating (ME) has been linked to improvement in binge eating disorder, but this approach in obesity management has shown conflicting results. Our aim was to assess the effect of ME associated with moderate energy restriction (MER) on weight loss in women with obesity. Metabolic parameters, dietary assessment, eating behaviour, depression, anxiety and stress were also evaluated. A total of 138 women with obesity were randomly assigned to three intervention groups: ME associated with MER (ME + MER), MER and ME, and they were followed up monthly for 6 months. ME + MER joined seven monthly mindfulness-based intervention group sessions each lasting 90 min and received an individualised food plan with MER (deficit of 2092 kJ/d - 500 kcal/d). MER received an individualised food plan with MER (deficit of 2092 kJ/d - 500 kcal/d), and ME joined seven monthly mindfulness-based intervention group sessions each lasting 90 min. Seventy patients completed the intervention. Weight loss was significant, but no statistically significant difference was found between the groups. There was a greater reduction in uncontrolled eating in the ME group than in the MER group and a greater reduction in emotional eating in the ME group than in both the MER and the ME + MER groups. No statistically significant differences were found in the other variables evaluated between groups. The association between ME with energy restriction did not promote greater weight loss than ME or MER.

Differences in the gut microbiota of women according to ultra-processed food consumption.

BACKGROUND AND AIMS: High consumption of ultra-processed food (UPF) has been associated with increased risk of obesity and other metabolic diseases, and this dietary pattern seems to be responsible for chronic changes in the gut microbiota. The aim of this study was to assess the associations of UPF with the gut microbiota and obesity-associated biometrics in women. METHODS AND RESULTS: This cross-sectional study examined 59 women. The following parameters were evaluated: food consumption using NOVA classification, anthropometric and metabolic parameters, and gut microbiome by next-generation sequencing. The mean age was 28.0 ± 6.6 years. The mean caloric intake was 1624 ± 531 kcal, of which unprocessed or minimally processed food (G1) accounted for 52.4 ± 13.5%, and UPF accounted for 31.4 ± 13.6%. Leptin levels adjusted for fat mass were negatively associated with G1 and positively associated with UPF. We found 15 species in the gut microbiota that correlated with G1 (3 positively and 12 negatively) and 9 species associated with UPF (5 positively and 4 negatively). CONCLUSION: Higher consumption of UPF was directly associated with leptin resistance, and this study suggests that the consumption of UPF or G1 may affect the composition of the gut microbiota.

Post-acute sequelae of SARS-CoV-2 infection: relationship of central nervous system manifestations with physical disability and systemic inflammation.

BACKGROUND: Despite the multitude of clinical manifestations of post-acute sequelae of SARS-CoV-2 infection (PASC), studies applying statistical methods to directly investigate patterns of symptom co-occurrence and their biological correlates are scarce. METHODS: We assessed 30 symptoms pertaining to different organ systems in 749 adults (age = 55 ± 14 years; 47% female) during in-person visits conducted at 6-11 months after hospitalization due to coronavirus disease 2019 (COVID-19), including six psychiatric and cognitive manifestations. Symptom co-occurrence was initially investigated using exploratory factor analysis (EFA), and latent variable modeling was then conducted using Item Response Theory (IRT). We investigated associations of latent variable severity with objective indices of persistent physical disability, pulmonary and kidney dysfunction, and C-reactive protein and D-dimer blood levels, measured at the same follow-up assessment. RESULTS: The EFA extracted one factor, explaining 64.8% of variance; loadings were positive for all symptoms, and above 0.35 for 16 of them. The latent trait generated using IRT placed fatigue, psychiatric, and cognitive manifestations as the most discriminative symptoms (coefficients > 1.5, p < 0.001). Latent trait severity was associated with decreased body weight and poorer physical performance (coefficients > 0.240; p ⩽ 0.003), and elevated blood levels of C-reactive protein (coefficient = 0.378; 95% CI 0.215-0.541; p < 0.001) and D-dimer (coefficient = 0.412; 95% CI 0.123-0.702; p = 0.005). Results were similar after excluding subjects with pro-inflammatory comorbidities. CONCLUSIONS: Different symptoms that persist for several months after moderate or severe COVID-19 may unite within one latent trait of PASC. This trait is dominated by fatigue and psychiatric symptoms, and is associated with objective signs of physical disability and persistent systemic inflammation.

Effects of clomiphene citrate on male obesity-associated hypogonadism: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Obesity causes secondary hypogonadism (HG) in men. Standard testosterone (T) replacement therapy improves metabolic parameters but leads to infertility. OBJECTIVE: To evaluate clomiphene citrate (CC) treatment of adult men with male obesity-associated secondary hypogonadism (MOSH). DESIGN: Single-center, randomized, double-blind, placebo-controlled trial. PARTICIPANTS: Seventy-eight men aged 36.5 ± 7.8 years with a body mass index (BMI) > 30 kg/m2, total testosterone (TT) ≤ 300 ng/dL, and symptoms in the ADAM questionnaire. INTERVENTION: Random allocation to receive 50 mg CC or placebo (PLB) for 12 weeks. OUTCOMES: (1) Clinical features: ADAM and sexual behavior questionnaires; (2) hormonal profile: serum TT, free T, estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and sex hormone-binding globulin (SHBG); (3) body composition: BMI, waist circumference, and bioelectric impedance analysis; (4) metabolic profile: blood pressure, fasting blood glucose, HbA1c, insulin, HOMA-IR, and lipid profile; (5) endothelial function: flow-mediated dilation of the brachial artery, quantitative assessment of endothelial progenitor cells and serum sICAM-1, sVCAM-1, and selectin-sE levels; (6) safety aspects: hematocrit, serum prostate-specific antigen, International Prostate Symptom Score, and self-reported adverse effects. RESULTS: There was an improvement in one sexual complaint (weaker erections; P < 0.001); increases (P < 0.001) in TT, free T, E2, LH, FSH, and SHBG; and improvements in lean mass (P < 0.001), fat-free mass (P = 0.004), and muscle mass (P < 0.001) in the CC group. CC reduced HDL (P < 0.001). No statistically significant differences were seen in endothelial function. CONCLUSIONS: CC appeared to effectively improve the hormonal profile and body composition. CC may be an alternative treatment for MOSH in adult men.

The Role of Exercise in a Weight-Loss Program on Clinical Control in Obese Adults with Asthma. A Randomized Controlled Trial.

RATIONALE: Clinical control is difficult to achieve in obese patients with asthma. Bariatric surgery has been recommended for weight loss and to improve asthma control; however, the benefits of nonsurgical interventions have been poorly investigated. OBJECTIVES: To examine the effect of exercise training in a weight-loss program on asthma control, quality of life, inflammatory biomarkers, and lung function. METHODS: Fifty-five obese patients with asthma were randomly assigned to either a weight-loss program plus exercise (WL + E group, n = 28) or a weight-loss program plus sham (WL + S group, n = 27), where the weight-loss program included nutrition (caloric restriction) and psychological therapies. The WL + E group incorporated aerobic and resistance muscle training, whereas the WL + S group incorporated breathing and stretching exercises. MEASUREMENTS AND MAIN RESULTS: The primary outcome was clinical improvement in asthma control over 3 months. Secondary outcomes included quality of life, lung function, body composition, aerobic capacity, muscle strength, and inflammatory/antiinflammatory biomarkers. After 3 months, 51 patients were analyzed. Compared with the WL + S group, the WL + E group demonstrated improved clinical control scores (median [25th to 75th percentile], -0.7 [-1.3 to -0.3] vs. -0.3 [-0.9 to 0.4]; P = 0.01) and greater weight loss (mean ± SD, -6.8% ± 3.5 vs. -3.1% ± 2.6; P < 0.001) and aerobic capacity (median [25th to 75th percentile], 3.0 [2.4 to 4.0] vs. 0.9 [-0.3 to 1.3] ml O2 × kg-1 × min-1; P < 0.001). These improvements in the WL + E group were also accompanied by improvements in lung function, antiinflammatory biomarkers, and vitamin D levels, as well as reductions in airway and systemic inflammation. CONCLUSIONS: Adding exercise to a short-term weight-loss program should be considered as a useful strategy for achieving clinical control of asthma in obese patients. Clinical trial registered with www.clinicaltrials.gov (NCT 02188940).

The effects of exercise training in a weight loss lifestyle intervention on asthma control, quality of life and psychosocial symptoms in adult obese asthmatics: protocol of a randomized controlled trial.

BACKGROUND: Asthma and obesity are public health problems with increasing prevalence worldwide. Clinical and epidemiologic studies have demonstrated that obese asthmatics have worse clinical control and health related quality of life (HRQL) despite an optimized medical treatment. Bariatric surgery is successful to weight-loss and improves asthma control; however, the benefits of nonsurgical interventions remain unknown. METHODS/DESIGN: This is a randomized controlled trial with 2-arms parallel. Fifty-five moderate or severe asthmatics with grade II obesity (BMI ≥ 35 kg/m(2)) under optimized medication will be randomly assigned into either weight-loss program + sham (WL + S group) or weight-loss program + exercise (WL + E group). The weight loss program will be the same for both groups including nutrition and psychological therapies (every 15 days, total of 6 sessions, 60 min each). Exercise program will include aerobic and resistance muscle training while sham treatment will include a breathing and stretching program (both programs twice a week, 3 months, 60 min each session). The primary outcome variable will be asthma clinical control. Secondary outcomes include HRQL, levels of depression and anxiety, lung function, daily life physical activity, body composition, maximal aerobic capacity, strength muscle and sleep disorders. Potential mechanism (changes in lung mechanical and airway/systemic inflammation) will also be examined to explain the benefits in both groups. DISCUSSION: This study will bring a significant contribution to the literature evaluating the effects of exercise conditioning in a weight loss intervention in obese asthmatics as well as will evaluate possible involved mechanisms. TRIAL REGISTRATION: NCT02188940.

The impact of obesity in hospitalized patients with COVID-19: a retrospective cohort study.

BACKGROUND: Obesity is believed to be a risk factor for COVID-19 and unfavorable outcomes, although data on this remains to be better elucidated. OBJECTIVE: To evaluate the impact of obesity on the endpoints of patients hospitalized due to SARS-CoV-2. METHODS: This retrospective cohort study evaluated patients hospitalized at a tertiary hospital (Hospital das Clínicas da Faculdade de Medicina da USP) from March to December 2020. Only patients positive for COVID-19 (real-time PCR or serology) were included. Data were collected from medical records and included clinical and demographic information, weight and height, SAPS-3 score, comorbidities, and patient-centered outcomes (mortality, and need for mechanical ventilation, renal replacement therapy, or vasoactive drugs). Patients were divided into categories according to their BMI (underweight, eutrophic, overweight and obesity) for comparison porpoise. RESULTS: A total of 2547 patients were included. The mean age was 60.3 years, 56.2% were men, 65.2% were white and the mean BMI was 28.1 kg/m2. SAPS-3 score was a risk factor for all patient-centered outcomes (HR 1.032 for mortality, OR 1.03 for dialysis, OR 1.07 for vasoactive drug use, and OR 1.08 for intubation, p < 0.05). Male sex increased the risk of death (HR 1.175, p = 0.027) and dialysis (OR 1.64, p < 0.001), and underweight was protective for vasoactive drug use (OR 0.45, p = 0.027) and intubation (OR 0.31, p < 0.003). CONCLUSION: Obesity itself was not an independent factor for worse patient-centered outcomes. Critical clinical state (indirectly evaluated by SAPS-3) appears to be the most important variable related to hard outcomes in patients infected with COVID-19.

Down the rabbit hole: reviewing the evidence for primary prevention of cardiovascular disease in people with obesity.

Obesity is a prevalent chronic disorder and a well-known risk factor for cardiovascular disease. However, the evidence of treating obesity for primary prevention of major cardiovascular events is still scarce and controversial. In this review, we provided a comprehensive description of the current evidence in treating obesity regarding cardiovascular protection. Bariatric surgery appears to be the most robust method to reduce events in people without established cardiovascular disease. High compliance to lifestyle interventions can further reduce cardiovascular risk. Concerning pharmacological therapies, a post hoc analysis from SUSTAIN-6 and a meta-analysis from STEP trials suggest that semaglutide, a GLP-1 receptor agonist, could reduce cardiovascular events in people without established cardiovascular disease. The first study addressed specifically a high-risk population with diabetes and, the second, low- or intermediary-risk individuals without diabetes. Tirzepatide, a novel dual GIP/GLP-1 agonist, although not yet tested in specific cardiovascular outcomes trials, could be an alternative since it induces loss in weight similar to the achieved by bariatric surgery. Therefore, extrapolated data in distinct baseline cardiovascular risk populations suggest that these two drugs could be used in primary prevention with the aim of preventing cardiovascular events, but the grade of this evidence is still low. Specifically designed studies are needed to address this specific topic.

"Anti-obesity medications" or "medications to treat obesity" instead of "weight loss drugs" - why language matters - an official statement of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM).

Obesity is largely undertreated, in part because of the stigma surrounding the disease and its treatment. The use of the term "weight loss drugs" to refer to medications for the treatment of obesity may contribute to this stigma, leading to the idea that anyone who wants to lose weight could use them and that short-term use, only in the active weight loss phase would be enough. On the contrary, the use of terms such as "medications to treat obesity" or "anti-obesity medications" conveys the idea that the treatment is directed at the disease rather than the symptom. This joint statement by the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) and the Brazilian Society of Endocrinology and Metabolism (SBEM) intends to alert the press, healthcare professionals and scientific community about the importance of the appropriate use of language, with the aim of improving obesity care.

Treatment with Antiobesity Drugs in Weight Regain After Bariatric Surgery: a Retrospective Cohort Study.

BACKGROUND: Bariatric surgery is the most efficient treatment for obesity. However, in some cases, weight regain can occur. Currently, it is unknown the best antiobesity medication (AOM) for such clinical situation. This study aims to evaluate the effect of AOM in patients with weight regain after bariatric surgery. METHODS: A retrospective cohort study from December 2010 to July 2019 with patients submitted to bariatric surgery that had weight regain and received AOM for at least 2 years. RESULTS: Of 96 patients that had weight regain in the analyzed period and received AOM, 16 were excluded from the analysis due to non-compliance (n = 7), treatment failure (n = 5), intolerable side effects with all available AOM (n = 2), or interaction with other medications (n = 2). Eighty patients were included in the analysis. The mean age was 59.0 ± 10.1 years, 88.8% were female, 91.2% white, and most of them were submitted to gastric bypass (87.6%). The mean preoperative and nadir weight after surgery were 127.9 ± 25.5 kg and 84.7 ± 22.8 kg, respectively. At the initiation of AOM, the mean baseline weight was 99.4 ± 23.1 kg. After 2 years of follow-up, there was significant weight loss in the groups treated with topiramate-alone (- 3.2 kg), topiramate plus sibutramine (- 6.1kg), and orlistat-alone or in combination (- 3.9kg). No statistical difference was observed in the sibutramine-alone group. CONCLUSION: Topiramate (alone or associated with sibutramine) and orlistat (alone or in combination) promoted significant weight loss after 2 years of use in patients submitted to bariatric surgery with weight regain.

Fecal microbiota transplantation in patients with metabolic syndrome and obesity: A randomized controlled trial.

BACKGROUND: Metabolic syndrome is a multifactorial disease, and the gut microbiota may play a role in its pathogenesis. Obesity, especially abdominal obesity, is associated with insulin resistance, often increasing the risk of type two diabetes mellitus, vascular endothelial dysfunction, an abnormal lipid profile, hypertension, and vascular inflammation, all of which promote the development of atherosclerotic cardiovascular disease. AIM: To evaluate the outcomes of fecal microbiota transplantation (FMT) in patients with metabolic syndrome. METHODS: This was a randomized, single-blind placebo-controlled trial comparing FMT and a sham procedure in patients with metabolic syndrome. We selected 32 female patients, who were divided into eight groups of four patients each. All of the patients were submitted to upper gastrointestinal endoscopy. In each group, two patients were randomly allocated to undergo FMT, and the other two patients received saline infusion. The patients were followed for one year after the procedures, during which time anthropometric, bioimpedance, and biochemical data were collected. The patients also had periodic consultations with a nutritionist and an endocrinologist. The primary end point was a change in the gut microbiota. RESULTS: There was evidence of a postprocedural change in microbiota composition in the patients who underwent FMT in relation to that observed in those who underwent the sham procedure. However, we found no difference between the two groups in terms of the clinical parameters evaluated. CONCLUSION: There were no significant differences in biochemical or anthropometric parameters, between the two groups evaluated. Nevertheless, there were significant postprocedural differences in the microbiota composition between the placebo group. To date, clinical outcomes related to FMT remain uncertain.

Proposal of an obesity classification based on weight history: an official document by the Brazilian Society of Endocrinology and Metabolism (SBEM) and the Brazilian Society for the Study of Obesity and Metabolic Syndrome (ABESO).

Obesity is a chronic disease associated with impaired physical and mental health. A widespread view in the treatment of obesity is that the goal is to normalize the individual's body mass index (BMI). However, a modest weight loss (usually above 5%) is already associated with clinical improvement, while weight losses of 10%-15% bring even further benefits, independent from the final BMI. The percentage of weight reduction is accepted as a treatment goal since a greater decrease in weight is frequently difficult to achieve due to metabolic adaptation along with environmental and lifestyle factors. In this document, the Brazilian Society of Endocrinology and Metabolism (SBEM) and the Brazilian Society for the Study of Obesity and Metabolic Syndrome (ABESO) propose a new obesity classification based on the maximum weight attained in life (MWAL). In this classification, individuals losing a specific proportion of weight are classified as having "reduced" or "controlled" obesity. This simple classification - which is not intended to replace others but to serve as an adjuvant tool - could help disseminate the concept of clinical benefits derived from modest weight loss, allowing individuals with obesity and their health care professionals to focus on strategies for weight maintenance instead of further weight reduction. In future studies, this proposed classification can also be an important tool to evaluate possible differences in therapeutic outcomes between individuals with similar BMIs but different weight trajectories.

Evaluation of fecal microbiota and its correlation with inflammatory, hormonal, and nutritional profiles in women.

The present study evaluated the gut microbiota profiles of 40 women and correlated them with their nutritional, inflammatory, and hormonal profiles. Stool and blood samples were collected, and anthropometric measurements were obtained from 20 women diagnosed with obesity ("case" group) and 20 women with weight in the normal range ("control" group). Bacteria belonging to two phyla, Firmicutes and Bacteroidetes, one class, Mollicutes, and four genera were evaluated by real-time polymerase chain reaction. Levels of 18 inflammatory cytokines were measured using the Luminex assay, and ghrelin and leptin levels were measured using enzymatic immunoadsorption assay. Mollicutes proportion differed significantly between the case and control groups, and a significant positive association was detected between the presence of Mollicutes and obesity. Statistically significant differences were observed between the proportions of Firmicutes and Bacteroidetes in the two groups, with a higher proportion of Firmicutes/Bacteroidetes ratio among the gut microbiota of women in the case group compared to those of the control group. Higher counts of Escherichia coli and Clostridium spp. were observed in the control group than in the case group, whereas higher counts of Lactobacillus spp. and Bacteroides spp. were detected in the case group than in the control group. There was a positive correlation between interleukin-6 (IL-6) and interferon-γ (IFN-γ) levels and the anthropometric variables and a negative correlation between IL-10 and these variables. Leptin and ghrelin concentrations differed significantly between the two groups and showed positive and negative correlation with obesity predictors, respectively. Therefore, gut microbiota was associated with obesity in women from this study group. Moreover, this microbiota was associated with inflammatory profiles and alterations in ghrelin and leptin levels.

Type 2 diabetes and metabolic surgery guidelines and recommendations should urgently be unified.

Metabolic surgery has been studied in the last decades as an effective and safe treatment for type 2 diabetes (T2D), and randomized controlled trials generally found surgery superior when compared with medical treatment. In 2016, the DSS-II Joint Statement recognized the importance of metabolic surgery in the treatment of T2D and urged clinicians to discuss, recommend, or at least consider this procedure for their patients. Diabetes societies also cogitate metabolic surgery as an option for T2D patients in their guidelines. However, there are some differences in recommendations that could lead a careful reader to some confusion. This was potentialized in a recent document published by the same DSS-II group concerning prioritization for surgery after the COVID-19 pandemic, in which the criteria suggested for an expedited recommendation that is not exactly evidence-based, and collided substantially with several clinical guidelines worldwide, especially with regard to secondary prevention of cardiovascular disease. A more harmonious discussion and unified guidelines between clinicians and surgeons are needed in order to provide the same message for those who read different articles.

Pharmacokinetics of oral levonorgestrel and ethinylestradiol in women after Roux-en-Y gastric bypass surgery.

BACKGROUND: Most patients undergoing Roux-en-Y gastric bypass (RYGB) are women in reproductive age. It is not known if bariatric surgery affects the pharmacokinetics of oral contraceptives. OBJECTIVES: The primary objective was to evaluate ethinylestradiol (EE) and levonorgestrel (LNG) absorption in women undergoing RYGB, compared with nonoperated controls matched by age and body mass index (BMI). A secondary objective was to assess whether the time since surgery and BMI in the postoperative period influenced the absorption parameters. SETTING: University hospital, Brazil. METHODS: This study was designed to compare the maximum plasma concentration (Cmax), the time to the peak plasma level (Tmax), the area under the curve (AUC0-8 and AUC0-∞) after a single dose of a combined oral contraceptive with 0.03 mg EE and 0.15 mg LNG among 20 women after RYGB and 20 controls. Blood samples were obtained for 8 hours. RESULTS: The mean LNG AUC0-8 and LNG AUC0-∞ were higher in RYGB group (P = .048 and P = .004, respectively). We found a positive correlation for LNG AUC0-8 (P = .045) and AUC0-∞ (P = .004) and the time since surgery, and we found a negative correlation for LNG Cmax (P = .018), AUC0-8 (P = .003), and AUC0-∞ (P = .001) and BMI. CONCLUSION: No significant differences were found in oral EE pharmacokinetics. The operated group showed higher mean LNG AUC0-8 and AUC0-∞ but it was not considered clinically significant. The present study suggests that RYGB may not affect EE and LNG absorption.

Should the Same Safety Scrutiny of Antiobesity Medications be Applied to Other Chronic Usage Drugs?

Obesity treatment is highly stigmatized, mainly because of the stigma of obesity itself. The frequent withdrawal of medications, lorcaserin being the last example, contributes to this stigma, but it is also probably a reflection of it, as data suggest that the threshold for a withdrawal is lower than with other classes of drugs. Safety should always be an absolute priority for every new medication, especially when used on a chronic basis; however, the safety scrutiny given to antiobesity medications is not given for other medications, such as postmenopausal hormone therapy and central nervous system drugs for psychiatric use. The withdrawal of medications for obesity can also impact future research in the area, so we need transparency and equality. Transparency in knowing exactly what reason led to a drug being discontinued and equality in long-term safety should be a concern with any medication prescribed for chronic diseases.

Melatonin deficiency decreases brown adipose tissue acute thermogenic capacity of in rats measured by 18F-FDG PET.

OBJECTIVE: Melatonin has been shown to increase brown adipose tissue (BAT) mass, which can lead to important metabolic effects, such as bodyweight reduction and glycemic improvement. However, BAT mass can only be measured invasively and. The gold standard for non-invasive measurement of BAT activity is positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-d-glucose (18F-FDG PET). There is no study, to our knowledge, that has evaluated if melatonin influences BAT activity, measured by this imaging technique in animals. METHODS: Three experimental groups of Wistar rats (control, pinealectomy, and pinealectomy replaced with melatonin) had an 18F-FDG PET performed at room temperature and after acute cold exposure. The ratio of increased BAT activity after cold exposure/room temperature was called "acute thermogenic capacity" (ATC) We also measured UCP-1 mRNA expression to correlate with the 18F-FDG PET results. RESULTS: Pinealectomy led to reduced acute thermogenic capacity, compared with the other groups, as well as reduced UCP1 mRNA expression. CONCLUSION: Melatonin deficiency impairs BAT response when exposed to acute cold exposure. These results can lead to future studies of the influence of melatonin on BAT, in animals and humans, without needing an invasive evaluation of BAT.

Melatonin Increases Brown Adipose Tissue Volume and Activity in Patients With Melatonin Deficiency: A Proof-of-Concept Study.

Melatonin, a pineal hormone synthesized at night, is critical for the synchronization of circadian and seasonal rhythms, being a key regulator of energy metabolism in many animal species. Although studies in humans are lacking, several reports, mainly on hibernating animals, demonstrated that melatonin supplementation and a short photoperiod increase brown adipose tissue (BAT) mass. The present proof-of-concept study is the first, to our knowledge, to evaluate BAT in patients with melatonin deficiency (radiotherapy or surgical removal of pineal gland) before and after daily melatonin (3 mg) replacement for 3 months. All four studied patients presented increased BAT volume and activity measured by positron emission tomography-MRI. We also found an improvement in total cholesterol and triglyceride blood levels without significant effects on body weight, liver fat, and HDL and LDL levels. Albeit not statistically significant, fasting insulin levels and HOMA of insulin resistance decreased in all four patients. The present results show that oral melatonin replacement increases BAT volume and activity and improves blood lipid levels in patients with melatonin deficiency, suggesting that melatonin is a possible BAT activator. Future studies are warranted because hypomelatoninemia is usually present in aging and appears as a result of light-at-night exposure and/or the use of ß-blocker drugs.