Breakfast time is the best time to eat fruits. While you sleep, your liver burns up its glycogen to supply needed glucose to the brain during your nightly fast. When liver glycogen levels begin to dip a signal is sent to the brain to start breaking down muscle protein to convert amino acids into glucose for the brain. When you wake in the morning you are a muscle-burning machine. At this time of day you will not have to worry about fructose being converted to fat, so eat up. The fructose will be put to good use for restocking the liver glycogen levels and switching off the signal to burn muscle protein.
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If you eat fruit on an empty stomach, it will not mix with other foods and cause fermentation and rot. If you eat a piece of fruit before a meal then you are taking up space in your stomach that a higher calorie piece of food would have occupied. If you do not have a stomach problem, then eat fruit before a meal will give the best results. This will make the nutrients in the fruit will be more absorbed by the body...!