Some people still eat the same portion sizes they ate when they were younger. But most people need fewer calories as they reach middle age and beyond. Maybe you could get by with just one or two slices of pizza instead of three or four. If you're still hungry, have an apple, a salad, or some other fruit or vegetable. Don't deny yourself.
Food is one of life's pleasures.
If you can't face the day without your favorite fattening foods, eat just a very small portion. If you don't deny yourself, you might not feel compelled to cheat. Think before you drink. Don't forget that soft drinks, fruit drinks, alcoholic beverages, Frappucinos and other fancy coffee drinks, and even healthy beverages like orange juice and low-fat milk usually have somewhere between 100 and 200 calories per serving. Water, seltzer, coffee, and tea are essentially calorie-free.