Introduction
It is believed that the time of day of food intake has an effect on health. For example skipping breakfast is associated with an increased risk of obesity whereas regular meal patterns are associated with a reduced risk of obesity. However currently few studies have investigated when people consume food throughout the day. Here we use Latent Class Analysis (LCA) to investigate the hourly eating patterns of UK adults.

Method
Data from four daily food diaries for 1946 men and 2792 women from the 2008-2014 National Diet and Nutrition Survey (NDNS RP) were analyzed. For every hour of the day we calculated whether an Eating Occasion (EO) had occurred.  We defined an EO to have occurred if more than 210kJ had been eaten in a 15 minute period. LCA was used to separate people into three distinct eating classes and also to calculate the probability of an EO occurring for each class for every hour of the day. We then related eating pattern latent class to socio demographics.

Results
We identified three patterns of eating: a standard eating class, a later eating class who ate lunch and dinner slightly later than the standard class, and an irregular eating class who were less likely to eat meals at set times. Figure 1 shows the probability of eating in a particular hour of the day for individuals in each class. The proportion of men and women in each class is provided underneath figure 1.  Table 1 shows daily EO frequency, average time between eating occasion, and daily energy intake by eating pattern class. We found evidence for both men and women (p<0.0001 and p<0.0001) that older people eat earlier. We found evidence (men p=0.0001 and women p=0.0033) that single people are more likely to graze. We found evidence that being from a more advantaged socioeconomic background was associated with eating later (men p=0.0005 and women p=0.0314). And we found evidence that being more highly qualified was associated with eating later (men p=0.0003, women p=0.0001). 

Conclusion
Our results suggest that people fall into distinct eating classes and that later eating is associated with various socioeconomic factors. It would be interesting to next investigate how eating time patterns identified via LCA are associated to health outcomes.

Contact Information
Raoul.Mansukhani@lshtm.ac.uk

Investigating eating time patterns in UK adults from The 2008-2012 National Diet and Nutrition Survey