How can you overcome these misconceptions about healthy eating? First, review your usual dietary habits. For a week, write down what you eat for every meal and snack, including the amount and the timing. "An honest evaluation can give you a clear idea of where you need to improve," says Fung. Next, adopt some small changes that can help fill in the gaps and expand your current good eating habits. Here are some suggestions.

Don’t be too ambitious. You don’t have to make multiple significant dietary changes at the same time to reap health benefits. "Change one thing in your diet for three to four weeks," says Fung. "Once it becomes a staple of your diet, move on to another area and repeat the process." For instance, if you drink soda three or four times per week, cut it back to twice a week, and drink a mixture of seltzer water and juice the other days. Eventually, drink soda once a week, and then try for none.

Adopt a vegetarian day. Once a week, go vegetarian for the entire day and eat nothing but fruits, vegetables, and whole grains (with perhaps a touch of low-fat dairy or eggs), and no processed foods. "This can help you recognize the types and amounts of foods you need to eat without the overwhelming pressure to do it all the time," says Fung. You may discover that vegetarian options are more appetizing than you expected. As you get more comfortable, increase it to twice a week, or even more often.