I do not really diet per se... I do monitor what I eat, and also try to burn off more calories than I take in. But I will indulge in my sweet tooth.
I do now measure and weigh my food. I am surprised at the amounts I was eating before, and the measured portions do not leave me hungrier. For example, I now eat no more than 1/2 cup of rice at a meal. For meat I keep it to below 6 ounces. I try to have half my plate taken up by salad, and I use my own homemade salad dressing (60% malt vinegar, 20% olive oil, 20% lemon or lime juice) that tastes great to me and is healthier than any store bought dressings. Eating out now, I find that most meals become 2 for me (eating half fills me up, I'll take home the other half for the next evening's dinner).
I have been able to transition my snacks to predominantly fruits (oranges, apples, pineapples, strawberries, blueberries, raspberries bananas) instead of candy. I also snack a lot on peanuts (high fat but, according to my DNA test fat is not a factor for me regarding weight gain) home popped popcorn, and greek yogurt (at last a yogurt that I like) that has high protein and almost no added sugar. I will make smoothies with the above fruits and protein powder, with a zero sugar drink mixed in for flavoring. I still indulge in chocolate, but mainly dark chocolate with higher cocoa content and lower added sugars.
Speaking of sugar, over the years I have cut WAY down on my sugar consumption. I do now track the "added" sugars I eat in a day. I have gone from 3-4 teaspoons of sugar in my tea ("would you like a little tea with your sugar?" people would ask me) to none (I use erythritol, the first "natural" sweetener that does not give me an aftertaste, and some cream w/o added sugar, since the fat content I am not concerned about). Since I now look at soda and fruit drinks as drinking sugar, I try to avoid or worse case, measure out what I drink to keep below the daily sugar limit. I more now drink my homemade concoction of decaffeinated ice tea and lemonade. It has some sugar but only enough so that a 3 liter pitcher totals 300 calories, I make it sweeter with erythritol.
With this I am managing to keep my weight on the low end of my 175-185 desired weight range. In fact, I am going to lower my range to stay below 180. This is down from 200 lbs 5 years ago. Along with lower weight, by blood pressure, resting heart rate, and stamina has improved. But, I still allow myself treats when I am at the low end or below. A Five Guys meal once a month (though that fills me up so much I do not need to eat anything else for that day). A jar of M&M peanuts from Costco that I take a month to eat. Dominos Pizza once a month (a single large one is 3 lunches or dinners for me). A slice of cake at social events. But when I do indulge, I try to balance it off somehow, if I can.