Snack quality and snack timing are associated with cardiometabolic blood markers: the ZOE PREDICT study

Background Snacking is a common diet behaviour which accounts for a large proportion of daily energy intake, making it a key determinant of diet quality. However, the relationship between snacking frequency, quality and timing with cardiometabolic health remains unclear. Design Demography, diet, health (fasting and postprandial cardiometabolic blood and anthropometrics markers) and stool metagenomics data were assessed in the UK PREDICT 1 cohort ( N = 1002) (NCT03479866). Snacks (foods or drinks consumed between main meals) were self-reported (weighed records) across 2–4 days. Average snacking frequency and quality [snack diet index (SDI)] were determined ( N = 854 after exclusions). Associations between snacking frequency, quality and timing with cardiometabolic blood and anthropometric markers were assessed using regression models (adjusted for age, sex, BMI, education, physical activity level and main meal quality). Results Participants were aged (mean, SD) 46.1 ± 11.9 years, had a mean BMI of 25.6 ± 4.88 kg/m 2 and were predominantly female (73%). 95% of participants were snackers (≥ 1 snack/day; n = 813); mean daily snack intake was 2.28 snacks/day (24 ± 16% of daily calories; 203 ± 170 kcal); and 44% of participants were discordant for meal and snack quality. In snackers, overall snacking frequency and quantity of snack energy were not associated with cardiometabolic risk markers. However, lower snack quality (SDI range 1–11) was associated with higher blood markers, including elevated fasting triglycerides (TG (mmol/L) β ; – 0.02, P = 0.02), postprandial TGs (6hiAUC (mmol/L.s); β ; – 400, P = 0.01), fasting insulin (mIU/L) ( β ; – 0.15, P = 0.04), insulin resistance (HOMA-IR; β ; – 0.04, P = 0.04) and hunger (scale 0–100) ( β ; – 0.52, P = 0.02) ( P values non-significant after multiple testing adjustments). Late-evening snacking (≥ 9 pm; 31%) was associated with lower blood markers (HbA1c; 5.54 ± 0.42% vs 5.46 ± 0.28%, glucose 2hiAUC; 8212 ± 5559 vs 7321 ± 4928 mmol/L.s, P = 0.01 and TG 6hiAUC; 11,638 ± 8166 vs 9781 ± 6997 mmol/L.s, P = 0.01) compared to all other snacking times (HbA1c remained significant after multiple testing). Conclusion Snack quality and timing of consumption are simple diet features which may be targeted to improve diet quality, with potential health benefits. Clinical trial registry number and website NCT03479866, https://clinicaltrials.gov/ct2/show/NCT03479866?term=NCT03479866&draw=2&rank=1