Instead, the AHA advises dieters to drop pounds in the traditional way -- by reducing fat intake and aiming for a weight loss of two to four pounds each month.

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In combination with properly balanced nutrition and caloric intake, increased physical activity can help with weight loss.

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Living in a zero-gravity environment poses risk of nutrient deficiency and bone loss, so keeping close tabs on food intake in space is crucial.

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This is because they rely on static models of weight loss rather than dynamic models that account for the way the body adjusts to reducing food intake by reducing energy expenditure.

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Nutritionists say that limiting caloric intake in a compressed time frame can lead to nutrient deficiencies, causing decreased immune function, dry skin and loss of muscle or bone density, for starters.

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