A Delayed Morning and Earlier Evening Time-Restricted Feeding Protocol for Improving Glycemic Control and Dietary Adherence in Men with Overweight/Obesity: A Randomized Controlled Trial

Abstract

We determined the effects of time-restricted feeding (TRF; 8 h/d) versus extended feeding (EXF; 15 h/d) on 24-h and postprandial metabolism and subjective opinions of TRF in men with overweight/obesity. In a randomized crossover design, 11 sedentary males (age 38 ± 5 y; BMI: 32.2 ± 2.0 kg/m²) completed two isoenergetic diet protocols for 5 days, consuming meals at 1000, 1300 and 1700 h (TRF) or 0700, 1400 and 2100 h (EXF). On Day 5, participants remained in the laboratory for 24 h, and blood samples were collected at hourly (0700-2300 h) then 2-hourly (2300-0700 h) intervals for concentrations of glucose, insulin and appetite/incretin hormones. Structured qualitative interviews were conducted following completion of both dietary conditions and investigated thematically. Total 24-h area under the curve (AUC_total) [glucose] tended to be lower for TRF versus EXF (-5.5 ± 9.0 mmol/L/h, P = 0.09). Nocturnal glucose AUC was lower in TRF (-4.2 ± 5.8 mmol/L/h, P = 0.04), with no difference in waking glucose AUC or AUC_total for [insulin]. Attitudes towards TRF were positive with improved feelings of well-being. Barriers to TRF were work schedules, family commitments and social events. Compared to extended feeding, short-term TRF improved nocturnal glycemic control and was positively perceived in men with overweight/obesity.

Keywords: acceptability; appetite; diet; dietary patterns; fasting; glucose; insulin; metabolism; obesity.

Figure 1

Study design schematic. Participants visited the laboratory at Day 0 to have activity monitors attached, continuous glucose monitoring system (CGMS) inserted and pick up Days 1–4 of the diet (50% total energy intake (TEI) fat, 30% TEI carbohydrate and 20% TEI protein) to be consumed in a time-restricted feeding (TRF) (1000, 1300 and 1700 h) or extended feeding (EXF; 0700, 1400 and 2100 h) pattern, in a randomized order separated by a 10 day washout period (A), before returning at 0645 h on Day 5 for a 24-h laboratory trial (B).

Figure 2

Consolidated Standards of Reporting Trials (CONSORT) flow diagram of participant recruitment.

Figure 3

Venous glucose (A–C; n = 11), interstitial glucose (D–F) and venous insulin (G–I), non-esterified fatty acids (NEFA; J–L), triglyceride (M–O) concentrations, peak concentrations and total area under the curve (AUC) values, respectively, from participants with overweight/obesity (n = 10) throughout trial conditions of time-restricted feeding (TRF; black squares and lines) and extended feeding (EXF; white circles and dotted lines). Black triangles represent TRF mealtimes whereas grey triangles represent EXF mealtimes. Data are mean ± SD. p < 0.05 for * main effect of condition; # significantly different between conditions within time point; $ significantly different to baseline (0700 h; effect of time).

Figure 4

Three-hour postprandial meal peak and incremental area under the curve (iAUC) glucose (venous, A,B, and interstitial (CGMS), C,D), insulin (E,F), non-esterified fatty acids (NEFA, G,H) and triglyceride (I,J) concentrations for breakfast, lunch and dinner periods from participants with overweight/obesity (n = 10) throughout trial conditions of time-restricted feeding (TRF; black squares and bars) and extended feeding (EXF; white circles and bars). Black triangles represent TRF mealtimes whereas grey triangles represent EXF mealtimes. Data are mean ± SD. p < 0.05 for * main effect of condition.

Figure 5

Venous c-peptide (A,B), glucose-dependent insulinotropic polypeptide (GIP; C,D), glucagon-like peptide 1 (GLP-1; E,F), leptin (G,H), peptide tyrosine tyrosine (PYY; I,J) and cortisol (K,L) concentrations over time and AUC_total, respectively, from participants with overweight/obesity (n = 10) throughout trial conditions of time-restricted feeding (TRF; black squares and lines) and extended feeding (EXF; white circles and dotted lines). Black triangles represent TRF mealtimes whereas grey triangles represent EXF mealtimes. Data are mean ± SD. p < 0.05 for * main effect of condition; # significantly different between conditions within time point; $ significantly different to baseline (0700 h; effect of time).

Figure 6

Subjective hunger (A), appetite (B), fullness (C), satiety (D) and fatigue (E) responses to visual analogue scale questions (0–100 mm) from participants with overweight/obesity (n = 11) throughout trial conditions of time-restricted feeding (TRF; black bars) and extended feeding (EXF; white bars). Black triangles represent TRF mealtimes whereas grey triangles represent EXF mealtimes. Data are mean ± SD. p < 0.05 for # significantly different between conditions within time point; $ significantly different to baseline (0700 h; effect of time).