Brierley Wright, M.S., R.D.
June 07, 2010

I just finished booking a week-long summer vacation at the beach, and I can't wait! But a week at the beach also means a week in a bikini. I'm not sure which is going to be the bigger challenge-finding a week's worth of bikinis that I actually like or making my body bikini-worthy.

But with this diet trick, I'm thinking looking good in the bikini may not be that difficult.

As a registered dietitian and nutrition editor at EatingWell magazine, I know that I can prevent weight gain or even encourage weight loss-without dieting-just by eating more fiber, according to a recent study in The Journal of Nutrition. (Try these fiber-rich recipes to help you lose weight.)

Researchers followed the eating habits of women for nearly two years and found that those who increased their fiber intake generally lost weight. (Women who decreased the fiber in their diets gained.) Over the course of the study, the researchers found that boosting fiber by 8 grams for every 1,000 calories resulted in about 4½ pounds of weight loss.

Try it for yourself. If you're consuming 2,000 calories per day, aim to increase your fiber by 16 grams.

Here are 5 fresh summer foods that will help you get your fill:

Strawberries: A cup of halved strawberries offers 3 grams of fiber and about 50 calories. You'll also get more than a full day's recommended dose of vitamin C-an antioxidant that helps keep your skin looking younger. (Get luscious, sweet strawberry recipes here.)

Zucchini: You'll also get 3 grams of fiber in a cup of cooked zucchini, but only about 30 calories. Plus, zucchini contains lutein and zeaxanthin-two phytochemicals that accumulate in the eyes and help prevent age-related macular degeneration. AMD is a leading cause of blindness in older people, but much of the damage occurs decades earlier. Find delicious recipes for Zucchini-Walnut Bread and more zucchini and summer squash recipes here.

Green Beans: One cup of cooked green beans has 44 calories and boasts 4 grams of fiber. It's also an excellent source of vitamin K, a nutrient that research suggests is important for maintaining strong, healthy bones. (Find fresh recipe ideas for green beans here.)

Corn: You'll get 5 grams of fiber (and 177 calories) in a cup of cooked corn. Or in a large ear of corn, 3 grams and 127 calories. Like zucchini, corn provides the eye-health phytochemicals lutein and zeaxanthin. (Get easy, quick corn recipes here.)

Raspberries: A cup of raspberries has a whopping 8 grams of fiber-and for only 64 calories. Another boon: some of the fiber is soluble-in the form of pectin, which helps lower cholesterol. Savor them in low-cal, high-fiber Raspberry-Chocolate Chip Frozen Yogurt and more berry recipes.