From webmd: Here are some common diet mistakes that even food-savvy consumers make:
Healthy Eating Mistake No. 1: Buying Fresh Produce for the Entire Week
Once fruits and vegetables are harvested, they start losing some of their vitamins, minerals, and phytochemicals. So keeping them in the crisper all week long can mean robbing yourself of nutrition.
Healthy Eating Mistake No. 2: Buying Too Much Processed Food
Processed foods tend to have more sodium and saturated fat, and less fiber and nutrients. Instead, start with fresh, whole foods as much as possible. When you do choose convenience products, look for those that contain whole grains (like whole-wheat bread and hot dog buns, whole-grain tortillas, and whole-grain blend pasta), have no trans fat, and are low in saturated fat (like bottled marinara made with olive oil, light salad dressing made with canola or olive oil, and some broth- or tomato-based soups.)
Healthy Eating Mistake No. 3: Eating Out or Ordering Takeout More Often Than Not
“According to our research, the average American adult purchases a meal or snack from a restaurant 5.8 times per week,” says Annika Stensson, director of media relations for the National Restaurant Association.
Healthy Eating Mistake No. 4: Not Taking Advantage of Food Synergy
Do you peel your apples or tomatoes? Do you eat your veggie-rich green salad with fat-free dressing? Do you like to peel and chop your garlic right before adding it into your stir-fry or sauce? If you answered “yes” to any of the above, you are decreasing the availability to your body of important nutrients found in these foods.
That’s because there are all sorts of relationships between the various components within certain foods and between certain foods, a concept called “food synergy.” For example, certain phytochemicals in apple peel account for most of apples’ healthy antioxidant activity, so peeling apples isn’t the healthiest way to go.
Also, it’s a good idea to let your minced or chopped garlic rest for 15 minutes before proceeding with cooking, according to the American Institute for Cancer Research. This helps ensure that the enzymatic reaction that begins when garlic is chopped releases as much of the antioxidant allyl sulfur as possible — and thus maximizes the cancer-fighting benefits.
Healthy Eating Mistake No. 5: Avoiding High-Fat Plant Foods
The three foods that come to mind are avocados, nuts, and olives, which are relatively high in calories and fat but low in saturated fat. These foods contribute smart fats to our diet, and they come with fiber and phytochemicals, too.
Moderation is the key here. So enjoy a quarter of an avocado on sandwiches and in salads, or a handful of nuts as a snack or added to your salad, cereal, or pasta. Use a light drizzle of olive oil in cooking. And add olives to salads, sandwiches, and casseroles, or eat them as a snack.