From your 'My Hub' page (please see below)
On the left hand side of your account, you will see the side menu in where you can select 'Nutrition'.
Here you can then select 'Custom Food/Drinks' from the 4 options at the top of your page which will then show any foods you have created already.
To delete the item you can simply hit the bin icon to the right
By clicking on the food item itself you will be able to view and edit all of the nutrient information