there are a couple of ways on how mealtime cultures and environment can be a barrier to meeting the nutritional needs of an individual with dementia.
People with dementia tend to have a difficulty to follow a specified timeline activity, therefore it would be hard for them to follow mealtime culture such as eating 3 times a day on their own
Normal eating environment such as restaurant could also be a problem for people with dementia since they will hear a lot of noises in their mind that would stress them out
hope this helps