Effects of weight-neutral approaches compared with traditional weight-loss approaches on behavioral, physical, and psychological health outcomes: a systematic review and meta-analysis.

CONTEXT: Weight-neutral approaches for health are emerging therapeutic alternatives to traditional weight-loss approaches. The existing literature base comparing these approaches has not yet been systematically evaluated by a meta-analysis. OBJECTIVE: This review aims to determine if weight-neutral approaches are valid alternatives to weight-loss approaches for improving physical, psychological, and behavioral health outcomes. DATA SOURCES: Embase, Scopus, PsycINFO, PubMed, CINAHL, and the University of Queensland Library databases were searched. STUDY SELECTION: Peer-reviewed, experimental, or quasi-experimental studies that included weight-neutral and weight-loss arms and reported physical, psychological, or behavioral outcomes were eligible. A total of 525 studies were identified through initial database searches, with 10 included in the final analysis after exclusion criteria were applied. DATA EXTRACTION: Screening and eligibility assessment of studies followed the PRISMA protocol. The following outcomes were extracted: weight, body mass index, lipid and glucose variables, blood pressure, eating behavior, self-esteem, depression, quality of life, physical activity, and diet quality. DATA ANALYSIS: Studies were graded per the National Health and Medical Research Council (NHMRC) level-of-evidence tool and the Academy of Nutrition and Dietetics quality-evaluation tool. Effect sizes were examined as a meta-analysis of standardized and mean differences using a random-effects inverse-variance model with 95%CIs. Practice recommendations for each outcome were graded per NHMRC body-of-evidence guidelines. CONCLUSIONS: Weight-neutral approaches resulted in greater improvement in bulimia (P = 0.02), but no significant differences were observed for any other outcome. Weight-neutral approaches may be as effective as weight-loss methods for improving physical, psychological, and behavioral outcomes. Limitations include inconsistent definitions of both approaches and variable time frames of follow-up.

Is the Impact of Starvation on the Gut Microbiota Specific or Unspecific to Anorexia Nervosa? A Narrative Review Based on a Systematic Literature Search.

BACKGROUND: The role of the gut microbiota in Anorexia Nervosa (AN) has long been neglected by researchers, although the fact that the former is known to play an important role in health, disease and weight regulation. Cycles of overweight and underweight due to natural states of starvation and refeeding are normal in many vertebrates in their ecological niches. OBJECTIVE: The aim of this review was to compare the similarities and differences of the gut microbiota in eating disorders with conditions of fasting and refeeding in other vertebrates. METHOD: A systematic literature search was conducted in Pubmed and Web of Science to find all relevant studies examining the gut microbiota in eating disorders and different states of fasting in vertebrates for this narrative review. RESULTS: Gut microbiota appears to differ in AN versus normal-weight individuals. Induced fasting conditions in other vertebrates resulted in heterogeneous effects on gut microbiota with respect to their richness, diversity and community structures. The findings for hibernating animals were generally consistent. A decrease in microbial richness and diversity was observed in the hibernating animal compared to the active animal, and the community structures were linked to these conditions. Some similarities and differences between AN and different states of fasting in other vertebrates were found. CONCLUSION: The complexity of the relationship between fasting and gut microbiota is difficult to interprete. A deeper biological understanding is necessary to identify promising approaches for the modulation of the AN gut microbiota to support established psychotherapies.