Coming off of a stimulant, such as caffeine, can take your body a little while to readjust. If you have been doing stimulants for awhile, then it's normal to feel lethargic and lack motivation when coming off of them. Eating fruit, an apple, or even, honey before working out are good suggestions, but they won't do the trick for you until your body gets back to normal, which may take several weeks to months.
Caffeine stimulates the central nervous system. Your CNS has been used to riding a high for so long that when you come off of it and return to baseline you feel lethargic. No amount of fruit or food will help recharge your CNS, only time will.
Top 10 Caffeine Withdrawal Symptoms
Headache- A caffeine headache usually starts behind the eyes and then moves up the front of the head.
Sleepiness- This just isn’t your normal tiredness, this is sitting up straight but still can’t keep your eyes open tiredness.
Irritability- Everyone and everything gets on your last nerve. It’s best just to lock yourself in your room during this stage.
Lethargy- Forget about productivity at this stage because you’ll be unmotivated to do anything.
Constipation- Caffeine stimulates the bowel, so without its daily does the colon gets a little cranky too.
Depression- Caffeine withdrawal can take away all hope for living. Temporary blues are one thing, but if you already struggle with depression this could be a big issue.
Muscle Pain/Stiffness- If you normally have some caffeine prior to exercise then during caffeine withdrawal you could feel as though your muscles have weights strapped to them.
Lack of Concentration- Forget school, studying, brain surgery, or jet engine repair during this stage of withdrawal.
Flu-like symptoms- Stuffy nose, blocked sinuses and even vomiting have been reported by people withdrawing from caffeine.
Insomnia- Some people are strange and actually can’t sleep when going through caffeine withdrawal. http://www.energyfiend.com/caffeine-withdrawal-symptoms-top-ten