Self explanatory. What types of food did the average person living in this time period eat on a regular basis?
The American diet had largely been creolized by the mid-eighteenth century. That is to say, colonists were combining ingredients and techniques from two or more cultures to create 'hybridized' dishes. Different regions of the US already had different regional foods (think of Tex Mex, soul food, and so on in the modern era).
I cannot tell you about Philadelphia or Boston specifically, but I can tell you about the Northeast more generally. In 1796 a woman named Amelia Simmons living in New Haven used pumpkin in a pastry shell to make what we would probably call pumpkin pie today. Her recipe described the use of eggs, sugar, mace, nutmeg, and ginger. The heavy use of spices here shows how the Columbian exchange had altered American recipes. More specific to the question you asked, eastern spices had a significant role in Northeastern cooking.
Other than regional differentiation, the French, English, and Spanish colonists who claimed various parts of the US had different ways of eating. And even though that sort of experimentation - creolization - was evident, so too were familiar culinary traditions. Settlers from southern England, for instance, ate a great deal of soup, meat and vegetable stews, porridges with grains and beans, bread, and dairy products; the latter in particular was widely available along the East Coast. The diets of British colonists living in the Northeast during the latter half of the eighteenth century, then, would more likely than not have included both familiar dishes such as the ones I highlighted above, and the creolized ones I described earlier.