Food timing is a relevant factor in weight control. Eating at the “wrong” time could be a determining factor for the loss of synchrony between the circadian system and different metabolic processes affecting energy and adipose tissue metabolism and the obesity risk.
Recently, the team behind the current study, from the University of Murcia, Spain, demonstrated that the timing of eating may change the daily rhythms of diversity and abundance of microbiota, with opposite patterns between early or late eating.
They hypothesised that having a high-energy and high-sugar food such as chocolate during a short-term period of two weeks in the morning or in the evening, may affect energy balance and differentially impact body weight or body fat distribution due to changes in energy intake, substrate oxidation, sleep- and circadian-related variables, or microbiota composition and their metabolic activity.
A sample of 19 postmenopausal females (aged 52 ± 4 years) with healthy BMIs from Spain completed a randomised controlled cross-over trial. They were instructed to eat either 100 g of chocolate (~33% of their daily energy intake) in the morning (within 1 hr after waking time) or in the evening (within 1 h before bed time) or no chocolate at all, with a duration of two weeks for each intervention and washout periods in between, for a total duration of 9 weeks.
Participants abstained from eating any other chocolate and they recorded their daily dietary intake. Measurements included body weight, waist circumference, hunger/appetite assessments, body temperature and activity, sleep duration, and cortisol measurements from saliva. Volunteers also collected a stool sample in the morning on the first and penultimate day of each condition. Samples were analysed using 16S rRNA amplicon sequencing.
The resulting data indicates the participants did not gain significant body weight when eating chocolate but a reduced waist circumference was noted in the group eating chocolate in the morning (MC).
While the volunteers in the chocolate eating groups had an increase of energy intake (extra 542 kcal), they spontaneously reduced their ad libitum energy intake by 16% (296 ± 442 kcal/d) when eating chocolate, especially in the morning.
Participants were less hungry and appetite for sweets was greatly reduced when eating chocolate in the evening (EC) or the morning.
Volunteers increased physical activity +6.9% when consuming chocolate at evening/night, compared to control.
The MC group saw increased lipid oxidation. The authors suggest this be related to theobromine and other methylxanthines present in chocolate that have been shown to increase thermogenesis and lipid oxidation, or to the flavanols (epicatechin or catechin), as other foods with similar contents of epicatechin or catechin that have been shown to increase fat oxidation.
They ad: "As adipose tissue contributes to lipid oxidation, these differences in substrate oxidation may be accounting for the decrease in waist circumference when chocolate was eaten in the morning. Literature shows that good weight loss responders have higher lipid oxidation rates than those experiencing weight relapse."
Eating chocolate in the morning also appeared to decrease fasting glucose, which the authors hypothesise may be due to the cocoa reducing the rate of maronutrient digestion.
"Chocolate may improve glucose homeostasis by slowing carbohydrate digestion and absorption. Indeed, cocoa could reduce the rate and extent of macronutrient digestion by binding to and antagonizing digestive enzymes which may help explain the previously reported inverse relation between chocolate intake and Type 2 Diabetes Mellitus (T2DM) incidence."
When looking at changes in the microbiota of the different groups, the researchers found chocolate consumption during the evening significantly increased the production of SCFAs such as acetate and propionate and other minor fatty acids (isobutyrate, isovaleronate, and valeronate) as compared to no chocolate, while morning chocolate levels of SCFA were in between the two. The beneficial effect of chocolate intake was supported by the increased levels of Ruminococcus, which associated with higher acetate levels (P = .039), and the decreased levels of Lachnospiraceae genus, which associated with a reduction of acetate (P=0.026).
The authors suggest that increased SCFA production might be a good biomarker to explain, at least in part, the differences between the conditions. In addition to the effects on appetite, SCFAs have been associated with beneficial changes in intestinal permeability.
The authors note the small sample size and the lack of diversity in the sample means that larger scale studies are needed to further interrogate their results.
Source: The FASEB Journal
Hernández-González. T., González-Barrio. R., et al
"Timing of chocolate intake affects hunger, substrate oxidation, and microbiota: A randomized controlled trial"