Your first set of complete dentures can, at first, result in a curious sensation. While your teeth are essential for speech, and help to keep your jawbone and associated muscles in the correct configuration, what you might be most looking forward to is being able to eat a wider range of food. So why can eating be uncomfortable with your new dentures?
Firstly, did your dentist extract a few teeth to accommodate your new dentures? When there are only a few teeth remaining in the jaw (and they might be of questionable quality), your dentist may have opted to remove these. Complete dentures can be a more straightforward solution than partial dentures that must accommodate isolated teeth, with the end results far more effective from a patient's point of view.
Post-extraction, your dentist may have fitted you with immediate dentures. These will need to be modified after the soft tissues in your mouth have healed, but remember that these dentures can be sitting directly above an empty dental socket that's in the process of healing. This means that any bite pressure applied to the dentures will be directed toward your wound, which can be uncomfortable. This discomfort will ease as your dental sockets heal and close, and will soon fade entirely.
However, there may also be temporary discomfort even when no extractions were required. The acrylic denture plate that holds your prosthetic teeth sits atop your palate and gums. This means that bite pressure is absorbed by both your dentures and the underlying soft tissues. This differs from natural teeth, where the pressure is absorbed by the tooth, its periodontal ligaments, and your jaw. The pressure distribution arising from biting and chewing can be an unfamiliar experience at first, but your soft tissues will rapidly adapt and toughen.
The key is to not be overly ambitious at first. Your dentist can give you a list of recommended foods for the period immediately after your dentures are fitted, and it's just a case of starting with soft foods before progressively adding harder and chewier foods to your diet. Some chewy foods might be relatively soft (such as chewy sweets), but some excessively chewy foods can also be sticky, and have the potential to dislodge your dentures.
Some trial and error is to be expected as you experiment with different types of foods in the weeks after your dentures have been fitted. Please consult your dentist if any discomfort associated with chewing should linger, as the fit of your complete dentures may need to be adjusted.