Does when we eat influence what we eat?

By Dr. Ananya Mandal, MDAug 31 2020

A new study from the researchers at the Nutrition Innovation Centre for Food and Health (NICHE), Biomedical Sciences Research Institute, Ulster University, and Centre for Exercise Medicine, Physical Activity and Health Sports and Exercise Sciences Research Institute, Ulster University, Northern Ireland, looked at the effect of timing of food intake on metabolism and weight gain. The study titled, “Does when we eat influence what we eat? A secondary analysis of the UK National Diet and Nutrition Survey” is to be presented as a poster at the European and International Conference on Obesity (ECOICO 2020), held online this year (1-4 September 2020).

Image Credit: Dejan Dundjerski / Shutterstock

What was the study about?

The researchers explained that there had been recent studies that show that the timing of eating could play a role in metabolism and other physiological processes. They write that feelings of hunger often have a diurnal rhythm and increase in the latter part of the day. This could also increase the amount of food taken by individuals in the evening. They also added that both quality of diet, as well as quantity, could play a role in the prevention of non-communicable diseases. There have been studies showing an increased amount of food or energy intake (EI) in the diet in the evening could raise the risk of obesity.

The purpose of this study was to look at the association of evening EI with total EI as well as with the quality of diet followed.

What was done in this study?

For this study, the team of researchers used data from the UK National Diet and Nutrition Survey between 2012 and 2017 (Years 5 to 7). For 1,177 adult participants, the team used 4-day food diaries to gather the EI data. The participants were aged between 19 and 64 years. Some of the under reporters (1349 participants) were removed from the final analysis.

From the analyzed participants’ EI data a quartile grouping was made depending on percentage EI consumed after evening:

• Q1 lowest evening EI - <31.4 percent
• Q2 evening EI - >31.4 to 40.4 percent
• Q3 evening EI - >40.4 to 48.6 percent
• Q4 - highest evening EI - = >48.6 percent

Along with this, the Nutrient Rich Food Index (NRF) 9.3 was also used to assess the quality of diet based on the UK diet. Statistical tests were used to assess the differences in total daily EI between evening EI quartiles. Other factors, such as age and gender, were also taken into account to assess different diet quality scores between evening EI quartiles. Some of the disqualifying nutrients were free sugar, saturated fats, and sodium, and the qualifying nutrients were proteins, fibers, vitamins A, C, and D, minerals such as calcium, iron, magnesium, and potassium.

What was found

From the participants surveyed, the researchers noted that the average amount of energy consumed in the evening after 6 pm was almost 40 percent of the total EI (39.8 percent). Total EI was significantly different across the evening EI quartiles Q1, 2, 3, and 4. The group with the lowest EI Q1 consumed 8,437 ± 2,332.9 kJ per day. Those in the Q2, Q3, and Q4 consumed 9,284±2,538.8 kJ per day, 9,108± 2,114.7 kJ per day, and 9,156±2,208.8 kJ per day, respectively. Diet quality was also different across evening E1 quartiles. Those who consumed the greatest proportion of EI in the evening (i.e., those in Q4) significantly lower NRF 9.3 score at 438 compared to those in Q1 at 459, Q2 at 465, and Q3 at 463.

After 6 pm hours, the percentage of total sugars consumed decreased from Q1 to Q4. Consumption of fat and alcohol after 6 pm hours, however, increased.

Future plans and conclusions

The researchers concluded that the timing of food intake could play a role in metabolism. They called for more analysis to see if the EI distribution around the day and the types of foods consumed in the evening could be associated with measures of body composition and cardiometabolic health.

The team wrote, “Future research should explore the mechanisms involved in the effect of timing of EI on diet quality and overall energy intake, particularly in regards to the role feelings of hunger and satiety may play.” They explained that this could be a modifiable behavior that could be part of nutritional interventions. They concluded, “consuming a greater proportion of EI in the evening may be associated with a lower diet quality score.” They added that these findings could play a role in “measures of body composition and cardiometabolic health.”