Crononutrição, ingestão alimentar e controle do peso corporal: evidências de estudos populacionais e meta-análises

Abstract

Chrononutrition is an emerging field that investigates the impact of meal timing on health outcomes. This thesis explored the relationship between chrononutritional patterns, dietary intake, and overweight, resulting in two scientific articles. The first analyzes, at the population level, the trend toward delayed meal times among the Brazilian population over a decade and its relationship with energy and macronutrient intake. The second synthesizes, through a systematic review with meta-analysis, the available evidence on the effects of time-restricted eating in adults with overweight or obesity, highlighting the differences between isocaloric and non-isocaloric strategies. The first study had a cross-sectional design and was conducted using data from the 2008–2009 and 2017–2018 Household Budget Surveys (POF), analyzing 34,003 and 46,123 individuals, respectively. In both periods, dietary intake was assessed on two non-consecutive days using food records (2008–2009) and 24-hour recalls (2017–2018). Variables included the first and last intake time, eating midpoint, caloric midpoint, eating window, and distribution of calories throughout the day. Between 2008–09 and 2017–18, the last intake time was significantly delayed across all age groups, with the general population showing an average delay of 65 minutes (p < 0.005). Among the different age groups, adolescents showed the greatest changes, with a 48-minute delay in the eating midpoint (p < 0.005) and an impressive 138-minute delay in the caloric midpoint (p < 0.005). Additionally, the eating window increased by an average of 59 minutes in the general population (p < 0.005), with similar trends observed across all age groups. On the other hand, a significant reduction in the fasting windows of the Brazilian population was observed. The total fasting window decreased by an average of 64 minutes (p < 0.005), with specific reductions of 40 minutes among adolescents, 69 minutes among adults, and 75 minutes among older adults. Nighttime fasting (defined as the period between 7:00 p.m. and 7:00 a.m.) also showed a significant drop, with an average reduction of 55 minutes (p < 0.005), including 54 minutes among adolescents, 55 minutes among adults, and 59 minutes among older adults. In 2017–2018, first intake time showed a consistent association with lower energy and macronutrient intake across all age groups. Conversely, later eating windows and later last meal times were positively associated with higher energy and macronutrient intake across all age groups. In 2008–2009, both the eating midpoint and caloric midpoint showed positive associations with intake at all ages. However, in 2017–2018, these associations were not significant among adolescents. The second article is a systematic review with meta-analyses aimed at comparing the effects of time-restricted eating with isocaloric diet controls (analysis 1) and non-isocaloric controls (analysis 2) on anthropometric and body composition parameters in adults with overweight or obesity. Two authors independently conducted searches in Medline, Lilacs, EMBASE, and Central using MeSH terms; disagreements were resolved by a third reviewer. The main findings were that, in studies using non-isocaloric controls, the time-restricted eating group showed significant reductions in body weight [MD: -2.82 kg (95% CI: -3.49; -2.15)], fat mass [MD: -1.36 kg (95% CI: -2.09; -0.63)], and fat-free mass [MD: -0.86 kg (95% CI: -1.23; -0.49)]. In studies employing isocaloric control strategies, the time-restricted eating group showed significant reductions in body weight [MD: -1.46 kg (95% CI: -2.65; -0.26)], fat mass [MD: -1.50 kg (95% CI: -2.77; -0.24)], and fat-free mass [MD: -0.41 kg (95% CI: -0.79; -0.03)]. We conclude that meal timing over the decade showed a significant delay, with later food intake associated with higher energy and macronutrient consumption in both analyzed periods. Additionally, time-restricted eating demonstrated favorable anthropometric and clinical outcomes, even when caloric intake was isocaloric between intervention and control groups, suggesting that circadian effects may enhance the impact of caloric restriction on overweight.