Pretreatment Metabolic Status on Weight Loss Success in Interventions Applying Carbohydrate Control, Exercise, and Time Restricted Eating: A Scoping Review

OBJECTIVES: Despite ongoing disagreement among the obesity research community, we have seemed to arrive at a paramount conclusion: there is no one-size-fits-all approach for weight loss. Thus, it is imperative to identify individual and contextual factors affecting intervention response. Emerging data suggests that pretreatment metabolic status may influence weight loss success. The aim of this scoping review is to describe the current state of knowledge on the effects of pretreatment glycemia and insulinemia status on weight loss regimens prescribing varying amounts and types of carbohydrates, time restricted eating (TRE), and exercise. METHODS: Twelve studies met inclusion criteria. Databases searched included PubMed, Web of Science, EMABSE, and ERIC. Reference lists of identified articles were also examined for additional studies. Studies were included if they were original peer-reviewed research and weight change was analyzed based on pretreatment glycemia and/or insulinemia status. Articles were excluded if they did not specify weight loss prescription or report weight loss outcomes. RESULTS: People with high fasting plasma glucose (FPG) and type 2 diabetes at baseline tended to have greater weight loss carbohydrate-modified diets (e.g., high fiber, low glycemic load, and/or low carbohydrate). People with normoglycemia but elevated fasting insulin (FI) tended not to respond differently between diets. Thus, FPG and FI should be considered in combination for predicting weight loss outcomes among subgroups. TRE is efficacious for modest weight loss and ameliorating insulin resistance and may be especially useful for those with impaired glucose metabolism at baseline. We did not identify any studies investigating the effects of pretreatment glycemia and insulinemia status on weight loss achieved with exercise alone. CONCLUSIONS: Pretreatment glycemia and insulinemia may be a promising strategy for predicting weight loss success, especially with low carbohydrate diets in those with impaired glucose metabolism. However, most of the available evidence is derived from retrospective analyses. Future prospective studies should be designed to directly investigate these effects and may also consider utilizing adaptive treatment strategies to tailor interventions to baseline metabolic status. FUNDING SOURCES: Supported by the General Mills Bell Institute of Health and Nutrition.