Yes there is a reason for this 3PM naptime syndrome. It all has to do with your exercise and diet. If you start exercising say about 3-5 times a week and change your diet this will not occur. The key to avoiding the 3PM naptime feeling is to eat about 5-6 small meals a day. Healthy snacks and foods in moderation help to keep your metabolism going. What happens is if you dont eat breakfast and then have coffee, you get a sugar rush which usually lasts you to lunch. Then at lunch you eat and feel good for a couple or hours, but if you overeat your body actually does not know what to do with all the extra fat and sugars you intake and so it stores them and does not use them for energy. The key basically is to keep your body going on food at all times of the day so you do not starve your body. Just changing your eating habits will help combat the problem. Try one day with skippng breakfast, eating a big lunch, and then dinner later on that night. The next day start with a small breakfast, a snack around 10am, then a small lunch around 12 or 1230, then another snack at around 3 then dinner say around 7. You will not believe how much energy you will have! Breakfast is the most important meal and HEALTHY snakcs not chocolate bars and potato chips are best! Hope that helps