Try whole wheat-bread instead of white bread. Make all your grain foods whole-grain or wheat instead of white, which will cause spikes and crashes in blood sugar. You get the added benefits of filling fiber, which may also lower risk of heart disease and cholesterol.
Look for "partially hydrogenated oil" in your snacks and foods. Something can be labeled as "zero trans fat" as long as it's under .5g per serving. Even 1g trans fat a day has been shown to be hazardous to health. All beef has it naturally, so enjoy in moderation.
One of the easiest is switching from regular soda to diet- no, it's still not health food, but it is 0 calories versus 150 (per 12 oz can). Also, most diet sodas only have 1-2% sodium per serving. Diet energy drinks tend to be way higher (6-8% per serving! A can has 2-3 servings, yikes). Steer clear of fruit juices (110 cal per cup), have Crystal light instead (5 cal per cup). I'm not a huge fan of water unless I'm working out, so this one is a lifesaver.
Ease up on the creamy condiments and dressings! To put it in perspective- a 4 oz. serving of chicken breast has 110 calories, 1g of fat. 2 tbsp of ranch has 140 calories and 14g of fat- which will fill you up more? I don't think it's worth it! Try a bit of BBQ sauce, ketchup, mustard, hot sauce or honey mustard instead.
Stop snacking out of the bag- scoop a measured portion into a bowl. That way, there's no mystery on how much you really consumed.
Watch your booze intake. Stick to light beers (about 100 calories a bottle). Common mixed drinks have about 250-400 calories, some even more! Vodka sodas, about 100. You can even add crystal light to them for all the flavor of a girly mixed drink. Those little packets fit in the smallest of clutches!
Try baked or popped chips instead of potato chips or Cheetos.
Skim milk has about as much good nutrients as whole milk, without any of the fat and only half the calories. Anything you miss can be easily replenished with a vitamin supplement. So, have skim or light soy milk instead!
Good rule of thumb: Whole grains (carbs) before a workout, lean protein after.