The Effects of a Macronutrient-Based Diet and Time-Restricted Feeding (16:8) on Body Composition in Physically Active Individuals—A 14-Week Randomised Controlled Trial

Abstract

The number of people suffering from being overweight or obese has risen steadily in recent years. Consequently, new forms of nutrition and diets were developed as potential solutions. In the last years, the time-restricted feeding and continuous energy restriction via macronutrient-based diets were increasingly popular. Both diets were exclusively studied separately. A comparison of the two diets for people with a high body mass index despite regular physical activity has not yet been studied in detail. Therefore, this study aimed to compare the effects of these two diets on body composition and adherence. For this study, a total of 42 subjects (m = 21, f = 21) with a BMI above 25 were recruited from a local fitness gym. After a two-week familiarisation period, one of the two diets was followed over 14 weeks. Dietary behaviour was monitored throughout the period with a food diary. The primary measurement parameters were body weight, lean body mass, fat mass, body mass index, and waist and hip circumference. In addition, adherence was assessed and calculated by food diary and questionnaire. In total, the data of 35 participants (m = 14, f = 21) were analysed. Significant reductions in body weight, fat mass, body mass index, and waist and hip circumference were observed in both groups (p < 0.05). No significant change could be observed in lean body mass in either category. No group and gender differences were detected in any of the primary parameters. For the secondary parameters, a significantly higher adherence was observed in the time-restricted feeding group (p < 0.05). In addition, it can be assumed that an adherence of 60–70% cannot lead to positive changes in body composition. In conclusion, there were no differences between the two diets on the primary parameters. However, it seemed that time-restricted feeding can be better implemented in everyday life, and an adherence of more than 70% is required for both diets to prove effective.

Health effects of the time-restricted eating in adults with obesity: A systematic review and meta-analysis

“…Only the duration of the eating window differed between the TRE and control groups in the same study, the rest of the interventions (e.g., exercise and calorie restriction) were the same. Participants in three studies ( 26 , 29 , 30 ) were allowed to eat ad libitum . Participants in six studies ( 21 , 22 , 25 , 27 , 28 , 31 ) were advised to follow a calorie-restricted diet, one of which was to be combined with exercise ( 28 ).…”

“…All the studies included an intervention group with a TRE duration of 8 h ( 22 , 26 – 30 ), 10 h ( 25 , 31 ), and 12 h ( 21 ). For the control groups, the eating window was ≤12 h ( 22 , 28 , 31 ) or with no restriction ( 21 , 25 – 27 , 29 , 30 ). The duration of the intervention was 8 weeks ( 22 , 29 , 31 ), 12 weeks ( 26 , 30 ), 14 weeks ( 28 ), 39 weeks ( 25 ), and 12 months ( 21 , 27 ).…”

Is Intermittent Fasting Better Than Continuous Energy Restriction for Adults with Overweight and Obesity?

“…Irrespective of the duration of the intervention (short term [4–12 weeks] or long term [24–102 weeks]), weight loss with ADF and 5:2 fasting was comparable to that achieved by calorie restriction (CR). 10 , 14 , 15 , 25–34 Meanwhile, weight loss with TRE alone (1%–5% decrease from baseline over 8–12 weeks) 23 , 35 , 36 was not superior to that achieved with CR and was less than that observed with ADF or 5:2 fasting unless total calorie intake was restricted along with TRE. Thus, long-term TRE combined with an appropriate energy-restricted diet can enhance weight loss, but this is mainly attributed to CR.…”

“…In the long term, more people seem to have difficulty following IF than CR. CR (80% of the individual energy requirement) ↓5.1% at 12 weeks; ↓5.6% at 24 weeks; ↓4.9% at 50 weeks; ↓5.0% at 102 weeks; NA NA NA Control (no calorie restriction) NA NA NA NA TRE Lowe et al, 23 2020 USA N = 116 (m = 70, f = 46), ages 18~64 years, BMI 27 ~43kg/m 2 12 weeks 8-h TRE (12:00–20:00) ↓0.95% at 12 weeks NA NA NA No significant differences in weight loss, fat mass, fasting insulin, glucose, HbA1C, or blood lipids between two groups Control (no meal timing restrictions) ↓0.69% at 12 weeks NA NA NA Liu et al, 24 2022 China N = 118, ages 31.9 ± 9.1 years, BMI 28~45kg/m 2 12 months 8-h TRE (8:00–16:00) ↓10.6% at 6 months; ↓9.0% at 12 months ↓26.9% at 6 months; ↓21.3% at 12 months ↓22.4% at 6 months; ↓17.0% at 12 months ↓20.9% at 6 months; ↓17.9% at 12 months Similar reduction in body weight, body fat, or metabolic risk factors with IF and CR, TRE can lead to weight loss, mainly attributed to CR CR (man 1500~1800 kcal, women 1200~1500kcal) ↓10.1% at 6 months; ↓7.2% at 12 months ↓25.1% at 6 months; ↓16.9% at 12 months ↓16.2% at 6 months; ↓12.2% at 12 months ↓19.3% at 6 months; ↓13.6% at 12 months Isenmann et al, 35 2021 ...…”

Chrononutrition—When We Eat Is of the Essence in Tackling Obesity

“…However, due to the common mechanisms of an overall negative energy balance, which is involuntary in IF and TRF, they share certain molecular mechanisms that contribute to the overall energy homeostasis. Each of the above-mentioned strategies have challenges and potential barriers to adherence for a long-term weight-loss strategy, though the current view supports TRF as a promising tool with greater-than-ordinary adherence, a good safety profile, and socially acceptable flexible implementation [ 237 , 238 , 239 , 240 ]…”