Eating and drinking in Pakistan is a joy, most certainly, especially if you have a fondness for spicy food or Indian cuisine. Pakistani cuisine and Indian cuisine have a great many similarities between them, and a good number of the dishes you find in a typical Indian restaurant are also found in Pakistan as local delicacies. Perhaps the greatest similarities are with Pakistani cuisine and the cuisine of the more northern parts of India in particular: for example, that staple of Northern Indian cuisine, garam masala, is actually a staple of Pakistani food as well. That should tell you already what to expect from your food trips in the country.
There are a few differences, though. For one thing, Pakistani cuisine involves far more meat than the cuisines of its neighbours. Surveys are consistent in showing that Pakistanis eat more meat on average per annum than the average Indian. This should set you at ease if you happen to be fond of meat: the country boasts a marvellous array of kebab dishes and curries that involve a lot of protein and which should satisfy the most carnivorous traveller. Salads and greens are still strongly represented, though, and usually show up served with a variety of other dishes for the meal, with the carbohydrate portion being taken up by other flatbreads or rice. Most people are already familiar with the flatbreads of this region, from naan to roti. Keep an eye out for the bread they call paratha: most foreigners trying it for the first time discover it to be so filling that they treat it as a meal in itself, especially as paratha is so oily and often filled with savoury ingredients added to it.
Now when it comes to how to conduct yourself during a Pakistani meal, you just need to remember the basic courtesies. First of all, if you are eating at someone’s home, be courteous enough to sample a little of everything that has been prepared for you (unless you have an allergy to something, of course, in which case you should inform your host and ask if any dishes have the ingredient to which you are allergic). Second, be aware that most dishes here are eaten with the hands, especially those served with bread. Observe the people around you to figure out how to handle your meal and remember that the hand you use to bring food to your mouth must be the right, not the left. This goes for a good number of cultures in this part of the globe.
Finally, when it comes to your drink, it is advised to select bottled water or other safely packaged and sterile beverages as much as possible, especially if you have a sensitive stomach. If you have a hankering for liquor and feel that eating and drinking in Pakistan would be incomplete without it, rest assured that there are sufficient off-licenses (liquor stores) to see to your needs, as well as plenty of bars for non-Muslim foreigners in the hotels and a few (high-end) restaurants.