Beware the hidden fat foods which are normally those tasty party foods quiche, sausages, pork pie, salami, and dips are some examples. Of course biscuits, cakes and desserts should also be kept to a minimum and only eaten as a special treat.
When you buy yoghurt, go for low 'live bio' versions. These help to restore the 'good' bacteria that aid digestion.
Bread, potatoes and pasta are all carbohydrate foods that have received bad press in the past. On their own, these foods do not make you fat. However, if you have a big cheese sandwich, knob of butter on your potato (or have chips), or make a rich cream sauce for the pasta you will increase the amount of fat you are eating.
Alcohol taken in moderation can be beneficial to health, but if you are watching your weight, it is relevant to know that the calories from alcohol cannot be used as fuel for exercise, nor do they provide any vitamins, minerals or fibre.
The butter vs. margarine debate continues to rage. The best advice is not to eat a lot of either, but to eat a little of both. Extra Virgin Olive Oil is ideal for salads and Canola oil for cooking.
Dairy products are a high source of fat and cholesterol, BUT they do provide us with other beneficial nutrients. The best approach is to buy "low fat" versions of milk, cheese, yogurt etc. as they will provide you with all the nutrients without the fat element.
It is not necessary to cut meat out of your diet. Instead, buy the leaner cuts and trim off any fat. It is also recommended to eat oily fish (tuna, mackerel and herrings) at least 3 times a week as they contain the beneficial Omega 3 oil.
Finally, whoever said "a little of what you fancy does you good" was probably right - exercise moderation in all things and you cannot go too far wrong. It is not what you eat between Christmas and New Year that makes the difference but rather what you eat between New Year and Christmas.