The primary reason elderly people should decrease their caloric intake is that they spend most of the day at rest, and their food will quickly turn to fat.
Elder people have lower caloric intake because of low involvement in activities and mostly remains at resting condition. We know more energy is needed when a person perform more activities.
So we can conclude that the primary reason elderly people should decrease their caloric intake is that they spend most of the day at rest, and their food will quickly turn to fat.
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