Background: Time restricted eating (TRE) is a dietary strategy that may improve metabolic health. However, no studies have compared TRE with current practice (CP) in dietetics.
Hypothesis: TRE will not be inferior to CP to improve glycaemic control in individuals at risk of type 2 diabetes (T2D).
Aim: This qualitative study aimed to explore the experiences of participants who were enrolled in 6-month controlled weight loss interventions with 2-month follow-up to better understand the process of behaviour change and maintenance.
Methods: Fifteen participants who completed or dropped out from either a daily energy restriction or intermittent fasting group were recruited using maximum variation purposive sampling. In-depth, semi-structured interviews were conducted at the 2-month follow-up phase.
Preclinical data show that autophagy delays age-related disease. It has been postulated that age-related disease is-at least in part-caused by an age-related decline in autophagy. However, autophagic flux has never been measured in humans across a spectrum of aging in a physiologically relevant context.
View Article and Find Full Text PDFIntermittent fasting appears an equivalent alternative to calorie restriction (CR) to improve health in humans. However, few trials have considered applying meal timing during the 'fasting' day, which may be a limitation. We developed a novel intermittent fasting plus early time-restricted eating (iTRE) approach.
View Article and Find Full Text PDFGrowth differentiation factor 15 (GDF15) increases with acute fast in animals, and high GDF15 reduces food intake in rodents. We explored whether GDF15 was altered following intermittent fasting (IF) versus caloric restriction (CR), and associations with energy intake. Females with obesity received all foods at 70% (IF70 and CR70) or 100% of energy requirements for 8 weeks.
View Article and Find Full Text PDFBackground: Autophagy is a cellular process that cleanses cells and is particularly important during ageing. Autophagy has been extensively studied in vitro and in animal models and is known to be sensitive to nutrition. However, human data are limited because autophagic flux (autophagic degradative activity) has been challenging to measure in humans.
View Article and Find Full Text PDFObesity (Silver Spring)
February 2023
Objective: Time-restricted eating (TRE) restores circadian rhythms in mice, but the evidence to support this in humans is limited. The objective of this study was to investigate the effects of TRE on 24-hour profiles of plasma metabolites, glucoregulatory hormones, and the subcutaneous adipose tissue (SAT) transcriptome in humans.
Methods: Men (n = 15, age = 63 [4] years, BMI 30.
Objectives: Intermittent fasting (IF) activates autophagy in cardiac muscle and pancreatic islets. We examined the effect of IF on markers of autophagy in liver and skeletal muscle in mice and in humans.
Methods: Ten-wk-old C57 BL/6 J male mice were ad libitum (AL) fed a high-fat diet (HFD) or chow diet for 8 wk, before randomization to AL or IF (24-h fast, 3 non-consecutive days per week) for 8 wk (8-16 per group).
Objective: We sought to examine the effects of 8 wk of time-restricted eating (TRE) on glucose metabolism and the adipose tissue transcriptome during a metabolic ward stay in men with obesity.
Methods: In a single-arm, pre-post trial, 15 men (ages 63 ± 4 y, body mass index = 30.5 ± 2.
Human trials that compare intermittent fasting (IF) to calorie restriction (CR) with psychological, behavioral and cognition outcomes are limited. We hypothesized that there would be no difference between CR and IF on perceived eating behaviors, mood, sleep quality, quality of life (QOL) and cognition in women with overweight and obesity. In this prespecified secondary analysis of an open-label, single center, parallel assignment, randomized controlled trial, healthy women with overweight or obesity (N = 46, mean [SD] age 50 [9] years, BMI 32.
View Article and Find Full Text PDFCurr Opin Clin Nutr Metab Care
July 2021
Purpose Of Review: Glucose metabolism is under circadian regulation, with insulin secretion and sensitivity being highest in the morning as compared to the evening. The present review will discuss the existing evidence for the role of meal and macronutrient timing to improve glucose metabolism and reset circadian clocks, with a focus on the evidence in humans.
Recent Findings: Shortening the daily eating window (also known as time-restricted eating), or skewing food intake towards breakfast and away from the evening meal both improve glucose control in people with impaired glucose metabolism.
Time-restricted feeding (TRF) initiated early during the dark phase prevents the metabolic consequences of a high-fat diet in rodent models. However, the metabolic consequences of delaying the initiation of TRF, akin to breakfast skipping in humans, is unclear. We assigned 8-week-old male C57BL/6J mice (n = 192) to chow or high-fat diet ad libitum (AL) for 4 weeks, before randomization to continue AL or 10 h of TRF, initiated at lights off (TRFe) or 4-h after lights off (TRFd) for a further 8 weeks.
View Article and Find Full Text PDFContext: Impaired lipid metabolism is linked with obesity-associated insulin resistance, which may be reversed by caloric restriction (CR).
Objective: In a secondary analysis of a randomized controlled trial, we compared the effects of intermittent fasting (IF) and CR on markers of lipid metabolism in muscle.
Design: Seventy-six women (body mass index, 25-40 kg/m2) were randomly assigned to 1 of 3 diets for 8 weeks and provided foods at 70% (CR70 and IF70) or 100% (IF100) of energy requirements.
Objective: This study aimed to examine the effects of intermittent fasting (IF) on mRNA levels of peripheral clock genes in skeletal muscle and subcutaneous adipose tissue (SAT) in women with obesity.
Methods: Women were randomized to one of two IF protocols and provided with all foods at 100% or 70% of calculated weekly energy requirements for 8 weeks. Breakfast was consumed before a 24-hour fast, which was initiated on three nonconsecutive days per week.
Background: Intermittent fasting (IF) is proposed as a viable alternative to moderate calorie restriction (CR) for weight loss and metabolic health, but few long term randomized trials have been conducted. This protocol paper describes the rationale and detailed protocol for DIRECT study (Daily versus Intermittent Restriction of Energy: Controlled Trial to Reduce Diabetes Risk), comparing long term effectiveness of IF versus CR on metabolic health in individuals who are at increased risk of developing type 2 diabetes.
Methods: Anticipated 260 non-diabetic men and women aged 35-75 years, BMI 25-50 kg/m with score ≥12 on the Australian Diabetes Risk (AUSDRISK) calculator will be recruited into this open-label, multi-arm, parallel group sequential randomized controlled trial.
This study determined the effects of increasing loads of whey protein on plasma amino acid (AA) concentrations, and their relationships with gastric emptying, blood glucose- and appetite-regulatory hormones, blood glucose and energy intake. Eighteen healthy lean men participated in a double-blinded study, in which they consumed, on 3 separate occasions, in randomised order, 450-mL drinks containing either 30 g (L) or 70 g (H) of pure whey protein isolate, or control with 0 g of protein (C). Gastric emptying, serum concentrations of AAs, ghrelin, cholecystokinin (CCK), glucagon-like-peptide 1 (GLP-1), insulin, glucagon and blood glucose were measured before and after the drinks over 180 min.
View Article and Find Full Text PDFUnbiased and sensitive quantification of low abundance small proteins in human plasma ( hormones, immune factors, metabolic regulators) remains an unmet need. These small protein factors are typically analyzed individually and using antibodies that can lack specificity. Mass spectrometry (MS)-based proteomics has the potential to address these problems, however the analysis of plasma by MS is plagued by the extremely large dynamic range of this body fluid, with protein abundances spanning at least 13 orders of magnitude.
View Article and Find Full Text PDFObjective: This study compared the effects of daily calorie restriction (DR) versus intermittent fasting (IF) on markers of inflammation and extracellular matrix deposition in adipose tissue and skeletal muscle in a controlled feeding trial in women with overweight or obesity.
Methods: Women (N = 76) were randomised to one of three diets and provided with all foods at 100% (IF100) or 70% (IF70 and DR70) of calculated energy requirements for 8 weeks. IF groups ate breakfast prior to fasting for 24-h on 3 non-consecutive days/week.
Objective: Intermittent fasting (IF) may limit metabolic adaptations that reduce energy expenditure, potentially by stimulating white adipose tissue (WAT) browning. The aim of this study was to examine the effects of 8 wk of IF on energy metabolism and markers of WAT browning in lean and diet-induced obese mice and in women who were overweight or obese.
Methods: Male C57 BL/6 J mice were fed chow or a high-fat diet (HFD; 43%) for 8 wk before undergoing IF (3 non-consecutive d/wk) for an additional 8 wk.
Objective: This study aimed to assess the effects of 9-hour time-restricted feeding (TRF), early (TRFe) or delayed (TRFd), on glucose tolerance in men at risk for type 2 diabetes.
Methods: Fifteen men (age 55 ± 3 years, BMI 33.9 ± 0.
Intermittent fasting (IF) increases lifespan and decreases metabolic disease phenotypes and cancer risk in model organisms, but the health benefits of IF in humans are less clear. Human plasma derived from clinical trials is one of the most difficult sample sets to analyze using mass spectrometry-based proteomics due to the extensive sample preparation required and the need to process many samples to achieve statistical significance. Here, we describe an optimized and accessible device (Spin96) to accommodate up to 96 StageTips, a widely used sample preparation medium enabling efficient and consistent processing of samples prior to LC-MS/MS.
View Article and Find Full Text PDFObjective: This study aimed to compare intermittent fasting (IF) versus continuous energy intakes at 100% or 70% of calculated energy requirements on insulin sensitivity, cardiometabolic risk, body weight, and composition.
Methods: Women with overweight (n = 88; 50 ± 1 years, BMI 32.3 ± 0.
Background/objectives: Protein supplements, usually drinks rich in whey protein, are used widely for weight loss purposes in overweight adults. Information comparing the effects of whey protein on appetite and energy intake in men and women is limited. The objective was to compare the acute effects of whey-protein intake on energy intake, appetite, gastric emptying and gut hormones in healthy young men and women.
View Article and Find Full Text PDFProtein-rich supplements are used widely for the prevention and management of malnutrition in older people. We have reported that healthy older, compared to younger, adults have less suppression of energy intake by whey-protein-effects on appetite-related hormones are unknown. The objective was to determine the effects of intraduodenally administered whey-protein on glucose, gut hormone, and amino acid concentrations, and their relation to subsequent energy intake at a buffet meal, in healthy older and younger men.
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