It is well known that we are in the midst of an obesity epidemic and it's widely accepted that unhealthy eating behaviours are the biggest reason. Recently, the government has focussed on inverventions involving foods and drinks that are high in fat, salt and/or sugar (HFSS). However, this does not take into account the amount of processing that foods undergo - several recent studies have shown that increased consumption of ultra-processed foods (UPFs) are related to weight gain. As part of a wider grant, this proposal is specifically to use ALSPAC data collected from dietary diaries in childhood to examine dietary patterns associated with both HFSS and UPFs in the development of obesity.