The Elya Rabbah writes (170:11) that one should use utensils to eat with and refrain from using their hands. Additionally, one should refrain from taking large bites of food and make sure not to get any food particles caught in their beard or on their clothing. The Elya Rabbah concludes by stating all these guidelines should be followed even when one eats alone in his home.
The Piskei Teshuvos writes (170:11) that if it is accepted by the general public to eat a certain food with one's hands (i.e. jelly donuts, bagels, or pizza), there is nothing wrong with eating without utensils. However, the Piskei Teshuvos quotes others who say that it is best to be stringent in this area and always use a fork and knife.
Courtesy of Revach.net