The association of appetite and hormones (leptin, ghrelin, and Insulin) with resting metabolic rate in overweight/ obese women: a case-control study

No effect of circulating leptin on energy metabolism in normal weight or overweight/obese lactating mothers: The case-control Breastmilk and the Link to Overweight/Obesity and Maternal diet (BLOOM) study

BACKGROUND & AIMS

Pregnancy and lactation are associated with metabolic changes, including alterations in energy metabolism, which are closely linked to body mass and composition due to hormonal status. Therefore, the objective of this study was to investigate the energy metabolism in exclusively or predominantly breastfeeding mothers with normal weight (NW) and overweight/obesity (OW/OB) and evaluate its associations with fasting serum leptin.

METHODS

This cross-sectional BLOOM study was conducted among 39 mothers (n = 19 NW, n = 20 OW/OB) in 15.5 ± 1.2 weeks of lactation. The leptin was analyzed in a blood sample using an enzyme-linked immunosorbent assay, body composition was analyzed by dual-energy X-ray absorptiometry, and resting metabolic rate (RMR) was measured by indirect calorimetry method.

RESULTS

The average RMR for all groups was 1747.5 ± 281.9 kcal/d, with a statistically significant difference between groups (1932.7 ± 222.6 vs. 1550.5 ± 190.6, p < 0.001, respectively in the OW/OB and NW group). The OW/OB mothers had higher oxygen uptake (VO2) and exhaled carbon dioxide (VCO2), but not respiratory quotient (RQ), carbohydrate (CHO%) and lipid oxidation (FAT%). When analyzing correlations stratified by BMI category, we found that serum leptin was correlated with CHO% negatively, and with FAT% positively in the NW but not in OW/OB mothers. Additionally, serum leptin was a significant predictor of RMR, VCO2, VO2, CHO%, and RMR/kg of total body weight. However, after adjusting for confounders, the observed associations were no longer statistically significant (RMR: β = 0.113, 95% CI -0.354-0.319; VO2: β = 0.141, 95% CI -0.462-0.744; VCO2: β = 0.238, 95% CI -0.411-0.888; CHO%: β = -0.146, 95% CI -0.151-0.444; RMR/kg of total body weight: β = -0.294, 95% CI -0.831-0.244).

CONCLUSIONS

Our results did not support the hypothesis that leptin plays a role in regulating energy homeostasis during lactation.

Weight Loss Programs: Why Do They Fail? A Multidimensional Approach for Obesity Management

PURPOSE OF REVIEW

Despite the prevalence of weight loss programs, their success rates remain discouraging, with around half of individuals regaining lost weight within two years. The primary objective of this review is to explore the factors contributing to the failure of weight loss programs and to provide insights into effective weight management strategies.

RECENT FINDINGS

Factors contributing to the failure of weight loss programs include the impracticality of restrictive diets, potential metabolic impacts, limited focus on lifestyle changes, genetic predispositions, psychological influences, socioeconomic status, and medical conditions. A holistic approach considering these factors is crucial for safe and sustainable weight loss. Key findings indicate the importance of holistic approaches to weight management, including lifestyle modifications, medical interventions, and behavioral and psychological strategies. Effective weight loss strategies emphasize low-calorie, nutrient-rich diets, regular physical activity, and interventions tailored to individual needs. Combining multiple approaches offers the best chance of successful weight management and improved health outcomes. This review provides insights into the complexities of obesity management and the factors contributing to the failure of weight loss programs. It highlights the necessity of adopting a holistic approach that addresses dietary habits, physical activity, genetic factors, psychological well-being, and socioeconomic influences. Recommendations include implementing lifestyle modifications, medical interventions when necessary, and integrating behavioral and psychological support to achieve sustainable weight loss and mitigate the global health challenge posed by obesity.

Gestational Diabetes Mellitus and Colostral Appetite-Regulating Adipokines

Gestational diabetes mellitus (GDM) is a complex metabolic disorder that has short- and long-term effects on maternal and offspring health. This study aimed to assess the impact of maternal hyperglycemia severity, classified as GDM-G1 (diet treatment) and GDM-G2 (insulin treatment) on colostral appetite-regulating molecules. Colostrum samples were collected from hyperglycemic (N = 30) and normoglycemic (N = 21) mothers, and the concentrations of milk hormones were determined by immunoenzymatic assay. A difference was found for milk ghrelin, but not for molecules such as adiponectin, leptin, resistin, or IGF-I levels, in relation to maternal hyperglycemia. The colostral ghrelin in the GDM-G1 cohort (0.21 ng/mL) was significantly lower than for GDM-G2 (0.38 ng/mL) and non-GDM groups (0.36 ng/mL). However, colostral resistin was higher, but not significantly, for GDM-G1 (13.33 ng/mL) and GDM-G2 (12.81 ng/mL) cohorts than for normoglycemic mothers (7.89 ng/mL). The lack of difference in relation to hyperglycemia for milk leptin, adiponectin, leptin-adiponectin ratio, resistin, and IGF-I levels might be the outcome of effective treatment of GDM during pregnancy. The shift between ghrelin and other appetite-regulating hormones might translate into altered ability to regulate energy balance, affecting offspring's metabolic homeostasis.

Revisiting Resting Metabolic Rate: What is the Relation to Weight Fluctuations?

PURPOSE OF REVIEW

Despite the great progress in obesity-tackling strategies, a negative energy equilibrium between energy expenditure and energy intake remains the cornerstone in obesity management. The present review article aims to shed light on the complicated interrelations of resting metabolic rate to weight fluctuations.

RECENT FINDINGS

Energy expenditure depends on body composition and is highly affected by weight changes, exerting a significant role in subsequent weight regain and underlining the metabolic resistance that people with obesity face when dealing with weight maintenance. The main tissue involved in energy expenditure is fat-free mass, as opposed to fat mass, which exerts a substantially lower impact. Although people with obesity display higher energy expenditures than their lean counterparts, these decrease substantially in the setting of weight loss. Metabolic adaptation is the difference between measured and predicted RMR after weight loss, either via lifestyle modification or after obesity surgery. Plausible explanations for this include differences in body composition, with loss of fat-free mass playing a significant role. This becomes especially apparent in the setting of rapid and massive weight loss, as in the case of bariatric surgery. A better understanding of energy expenditure pathophysiology may aid in further enhancing weight loss and promoting weight maintenance in people with obesity.