Reference
Mazri FH, Manaf ZA, Shahar S, et al. Do temporal eating patterns differ in healthy versus unhealthy overweight/obese individuals? Nutrients. 2021;13(11):4121.
Key Take-Away
Higher energy intake earlier in the day and lower energy intake later in the day are more metabolically beneficial and reduce the risks of moving to metabolically unhealthy status.
Design
Cross-sectional, single-clinic, observational study
Participants
This study recruited 299 volunteers (73.6% women) in the Klang Valley region of Malaysia. All participants were government workers who did not work a swing shift (to control for circadian disruption as a confounder). Otherwise, the inclusion criteria included a body mass index (BMI) of 25.0 kg/m2 or greater (overweight/obese) and an age between 20 to 59 years (age: 40.3±6.9 years).
After investigators applied the study criteria, the 299 participants were divided into 126 (42%) metabolically unhealthy obese (MUO) participants and 173 (58%) metabolically healthy obese (MHO) participants.
Participants were excluded if they were pregnant or lactating, they had undergone bariatric surgery, or had a diagnosis of chronic disease including liver, heart, kidney disease, or cancer.
Intervention
Trained dietitians and nutritionists administered a 7-day retrospective Dietary History Questionnaire (DHQ).
Investigators analyzed the food measurements using Nutritionist ProTM software.
They averaged the times of the participants’ meals and calculated the midpoints to arrive at the temporal patterns of energy and macronutrient intakes. They classified these temporal patterns into early- and late-eating windows.
Meals eaten before the midpoint were considered the early-eating window, and meals after the midpoint were considered the late-eating window.
Study Parameters Assessed
Investigators conducted the study for 6 months (August 2019–January 2020).
The early- versus late-eating window was defined by determining the midpoint between the first and last meals for each subject, and then calculating if the majority of calories were eaten before (early-eating window) or after (late-eating window) this midpoint.
Laboratory values included fasting blood glucose, insulin levels. HbA1c, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, non-HDL cholesterol, triglycerides, and uric acid levels.
Investigators also measured waist circumference, height and weight, and blood pressure for metabolic health status parameters. To calculate body composition, they used a bioelectrical impedance analyzer (BIA).
Participants were classified as metabolically unhealthy obese (MUO) subjects if they met 3 or more of the 5 following criteria:
- Fasting blood glucose (FBG) greater than 5.6 mmol/L or drug treatment to control glucose
- Fasting triglycerides (TG) greater than 1.7 mmol/L or drug treatment to control lipids
- Fasting HDL-C less than 1.29 mmol/L for women; fasting HDL-C less than 1.03 mmol/L for men
- Systolic blood pressure of greater than 130 mmHg and diastolic blood pressure greater than mmHg or drug treatment to control hypertension
- Waist circumference (WC) greater than 80 cm for women; waist circumference greater than 90 cm for men
Metabolically healthy obese (MHO) participants were those who met 2 or less of the above parameters.
Investigators conducted a Night Eating Questionnaire (NEQ) to look for the presence of night-eating syndrome; they used 13 of the 17 items in this study, questions 1 to 12 and question 14. The scores ranged from 0 to 52, with values greater than 25 indicating night-eating syndrome.
In the Klang Valley area of Malaysia, 20% of the population has a split sleep schedule due to morning prayers. Investigators used the Munich Chronotype Questionnaire (MCTQ) to adjust for participants who had a split sleep schedule; this takes their midpoint of sleep to correct for sleep debt and create chronotypes of morning or evening.
Investigators administered the Global Physical Activity Questionnaire, (Malaysian version) to assess the physical activity of participants.
Primary Outcome
The study was designed to assess whether the time of day of energy and macronutrient intake is associated with metabolically healthy or unhealthy adiposity in overweight/obese individuals, as designated by an a priori criteria.
Key Findings
There were no significant differences in sleep traits, physical activity, lifestyle traits, or night-eating scores between the MHO and MUO participants.
Both the MHO and MUO participants were similar in mean age. There was no significant inherent difference in morning and evening chronotypes between the 2 groups.
When the investigators corrected for all lifestyle parameters such as sleep, physical activities, and lifestyles, they found that MHO participants consumed more than 60% of their energy during the early window. MUO participants consumed less than 60% of energy intake during the early window. Instead, the MUO participants consumed more than 40% of their energy during the late window.
MUO participants consumed a lower proportion of energy during the early window: 59.0% (P=0.008); carbohydrate: 30.6%, (P=0.021); protein: 9.7% (P=0.049).
MUO participants consumed a higher proportion of energy during the late window: 41% (P=0.008); carbohydrate, 18.1% (P=0.019); fat 13.1% (P=0.024).
Additional findings noted that the MUO group had significantly higher male participants, at 53% compared to 46.8% male participants in the MHO group (P=0.021).
The MUO participants had higher adiposity and both systolic and diastolic blood pressures higher than the MHO. The biochemical parameters for MUO participants were poorer than MHO participants, with the exception of total cholesterol, LDL cholesterol, and uric acid levels.
This research suggests eating higher energy intakes earlier in the day and lower energy intakes later in the day are metabolically beneficial. This was shown to be beneficial for morning and evening chronotypes. An additional prospective study needs to be conducted to understand if chrono-nutrition can metabolically delay the progression from metabolically healthy obesity to metabolically unhealthy obesity.
Transparency
The research for this study was funded by the Ministry of Higher Education. The authors did not make any disclosures.
Practice Implications
This study suggests that eating higher caloric intakes earlier in the day and reducing those caloric intakes later in the evening may be metabolically beneficial compared to eating later in the day.
The metabolic health status parameters that were used to define the “metabolically unhealthy” are also those that determine the presence of metabolic syndrome.1 Metabolic syndrome increases the risk for chronic diseases: heart disease, diabetes, and stroke.
This has strong eating implications when teaching people about healthy eating patterns with respect to the best times to eat meals and the composition of the meals.
This study may prove especially helpful when explaining the ramifications of eating during the day instead of skipping meals and eating larger meals in the evening. The increased risk of metabolic syndrome symptoms and obesity when eating higher energy amounts later in the evening was also noted in a small study by Gu C et al.2
With the rise in popularity of intermittent fasting, many people have taken to changing the times of their meals to later in the day, with the objective of losing weight and creating a healthier metabolic status.
While intermittent fasting can be a very successful approach to reducing metabolic syndrome parameters when applied correctly, this current study suggests that eating high-energy meals later in the day correlates with metabolic syndrome, which raises the risk for more serious chronic illnesses.
When teaching or speaking to patients about intermittent fasting, it is best to share information about timing windows and calorie-intake measurements, emphasizing that patients should aim for the early energy intake window and reduce high-energy intake later in the day. It is also helpful to run labs and repeat labs to make sure that metabolic parameters are improving with nutritional guidance.3
There is another interesting aspect of this study. Despite the fact that the overall population of this study was female (73.6%), there were significantly more men in the MUO group than in the MHO group. As we continue to look at educating people about healthy eating habits, perhaps there needs to be a specific emphasis on educating men about temporal eating habits to reduce their risks of metabolic syndrome and chronic disease related to eating habits.
