Never deprive yourself- if you deprive yourself of the food that you have been used to eating, like bacon or a few bites of chocolate before sleeping at night, you will ultimately fail.
People feel angry and bored by not being able to eat the usual food they have been accustomed.
A note of warning though: do not indulge too much. If you have comfort food like a large bag of chips or a bucket of fried chicken when you feel down, it is time to drop the habit. Put salt away- we are not only talking about the stuff you sprinkle when cooking. Salt affects the body's capacity to retain and expel water. More salt in your diet means increase in body fluid retention.
Avoid fat- if you like cooking, it is time to avoid putting that layer of fat when it is unnecessary. Usually people do not notice the extra fat because the act of adding fat (in the form of margarine or butter) has been a family practice for so long.
If you feel that food will be incomplete without the usual smear of butter or margarine, try substitutions. Good and tasty substitutes include baked beans and other such toppings.