When you only eat fruit, you're excluding a lot of valuable nutrients from your diet, says Marisa Moore, registered dietician and spokeswoman for the Academy of Nutrition and Dietetics.

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Laroche's study appeared in the Journal of the Academy of Nutrition and Dietetics.

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Rick Wilson, director of nutrition and dietetics at King's College Hospital London, said most cases of malnutrition were linked to other illnesses, which depressed patient's appetite.

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Marisa Moore, a registered dietitian with the Academy of Nutrition and Dietetics, says superfoods are healthy, but adding them to your plate won't simply melt the pounds away.

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"It can be really tricky if it's something with a background that's associated with livestock, " says Jacquelynn O'Palka, chair of the department of nutrition and dietetics at Indiana University-Purdue University Indianapolis.

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Studies in the Journal of the Academy of Nutrition and Dietetics and the American Journal of Preventive Medicine also support the benefits of journaling, although weight loss in both studies was modest.

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