A better approach is to make a few small changes at a time. Keeping your goals modest can help you achieve more in the long term without feeling deprived or overwhelmed by a major diet overhaul. Think of planning a healthy diet as a number of small, manageable steps—like adding a salad to your diet once a day. As your small changes become habit, you can continue to add more healthy choices.
Going gluten-free may be a popular trend, but unless you're actually gluten-intolerant or have celiac disease, plenty of reasons exist to continue eating whole grains. They're a tasty way to fill up on both soluble and insoluble fiber, which help you feel full for longer and keep bowel movements regular (oats, barley, and bulgur are especially high sources). Whole grains can also help prevent weight gain: in one study, women who ate whole grains like wheat germ and dark bread had a 49% lower risk of "major" weight gain over time.
For a 2,000-calorie daily diet, aim for 2½ cups of vegetables and 2 cups of fruit a day. If you consume more calories, aim for more produce; if you consume fewer calories, you can eat less. Include green, orange, red, blue/purple, and yellow vegetables and fruits. In addition to the fiber, the nutrients and phytochemicals in these foods may help protect against certain types of cancer and other diseases. Legumes, rich in fiber, can count as vegetables (though they have more calories than most vegetables). For more fiber, choose whole fruits over juice.