One quick thing I really liked about the parent is that they considered themselves a 2,500 calories/day kind of guy, whereas many people think 2,000 calories/day is standard. Cutting calories definitely works for most people(Rule of thumb: 3.5k calories = 1 lb), but a lot of people don't realize that they can differ from the 2000/day standard by quite a large margin. There are two main factors in determining the number of calories you should consume in a day: basal metabolic rate(BMR), and your level of exercise. You can search for some online calculators to give estimates of these, but the best method would be to find out what kind of diet(as in eating habits, not the cessation of eating) maintains your current weight steadily, and assume +/- some number, say 250. There's always wiggle room.
Just as a comparison, if someone tries to cut their diet down to 1500/day as the parent did, they may have very little change(if their metabolism burns at less than 2000/day on average), or they may be putting themselves at risk for malnutrition AND kick their metabolism into a much lower gear(if they're closer to 4-5k/day). And like it's been suggested, one of the hugely easy ways to cut down on unnecessary intake is to cut out raw sugars like soda or candy. An average banana will have about 100 calories in it, whereas a smaller chocolate bar will have 200 or more. Not to mention, the higher spike in blood sugar from the quickly digested chocolate will leave you much hungrier an hour later!
Of course, YMMV. Everyone is different, and pushing your intake far in either direction will get reducing gains and widely varied effects.