Adherence to Diet and Meal Timing in a Randomized Controlled Feeding Study of Time-Restricted Feeding

Abstract

Adherence is critical in feeding studies to determine the efficacy of dietary interventions. This time-restricted intake of meals (TRIM) investigation was a controlled feeding study that randomized 41 participants to follow 12 weeks of time-restricted feeding (TRF) or a usual feeding pattern (UFP). Adherence was optimized through careful screening and participant orientation, flexibility in beverages and seasonings, and frequent contact between participants and staff. Adherence was measured daily using a self-administered diary form. We calculated the percentage of participant-days with perfect adherence to meal timing (ate all meals within their designated time window) and to food consumption (ate all study food and no non-study food). Adherence was compared between study arms, days of the week, and weeks of the study period using generalized estimating equations (GEE) regression. There was perfect adherence to meal timing on 87% of participant-days and to food consumption on 94% of participant-days, with no significant difference by arm. In UFP, but not TRF, participants had lower adherence to meal timing over the weekend (p-value = 0.002) and during the first two weeks of intervention (p-value = 0.03). A controlled feeding study randomizing free-living individuals to different meal timings achieved a high degree of adherence to meal timing and food consumption, utilizing multiple strategies.

Obesity and Overweight: Probing Causes, Consequences, and Novel Therapeutic Approaches Through the American Heart Association's Strategically Focused Research Network

“…Note that a full list of the articles supported through this center is included within the reference section. 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 Figure 2 summarizes the center's key accomplishments.…”

Time-restricted eating improves health because of energy deficit and circadian rhythm: A systematic review and meta-analysis

“…Some research suggested that the threshold for the effect of TRE strategies was around 12 weeks when the intervention effect was likely to be the best with the highest dietary adherence, after which the effectiveness might decrease as the adherence rate lowered. 11 , 50 Therefore, the relevance of energy balance, the eating window, and body weight need to be rigorously assessed, and more objective measurements of daily energy intake and compliance are needed. 51 Although the weight loss magnitude was modest, subgroup analysis indeed showed the advantage of eating time-of-day in TRE.…”

“…Most were 8 and 12 weeks and lacked follow-up on the long-term effects of TRE strategies. Some studies 11 , 51 suggested that the intervention effect of TRE showed an inverted U-shaped curve that increased initially and then decreased with the intervention duration. However, in this meta-analysis, we were not able to perform a nonlinear meta-regression to test this hypothesis due to the limitations of the intervention duration lengths in the included studies.…”

“…Moreover, self-reported measures of adherence, such as remote video by Skype or daily adherence logs, rely on participants’ honesty and may be affected by social desirability bias. 11 , 62 In addition to using adherence to predict long-term weight maintenance, the distribution of protein and carbohydrate intake is crucial for understanding the full benefit of TRE as these macronutrients are vital to modifying body composition and glycemic levels. 63 , 64 Biological hunger and satiety can result in urges to eat and are related to TRE eating time.…”

“…As a subset of the CR strategy, TRE is superior to continuous CR and other types of intermittent fasting due to the alignment of the eating window with the time of day. 9 The concomitant reduction in energy intake 10 and considerable adherence 11 may facilitate long-term weight loss and metabolic improvements. 12 , 13 The earliest studies on time-restricted feeding (TRF) demonstrated benefits to metabolic health and lifespan in animals, 7 , 14 , 15 , 16 but the extent to which these findings from animal models are translatable to humans has not been determined.…”