This study found that obese women who were served three large meals instead of six small meals per day had much lower postprandial (after eating) levels of triglycerides in their blood, which may reduce the risk for cardiovascular disease.

One of the authors of the study (Heden) was quoted as saying "The mass media and many health care practitioners often advocate eating several small meals throughout the day. However, when we examined the literature, we didn't find many studies examining or supporting this popular claim. This lack of research led to our study, which is one of the first to examine how meal frequency affects insulin and blood-fat levels in obese women during an entire day of eating."

Our body needs to secrete bile from the liver/gallbladder, acid from the stomach, and digestive enzymes from the pancreas in order to properly digest food. Building up an "appetite" includes preparing all these digestive components. If your digestive tract is being constantly bombarded by small quantities of food; how can it know when to secrete, when to digest, and when to relax the sphincter at the bottom of the stomach and release the partially digested food into the intestines?

Grapefruit inhibits the ability of the body to break down some prescriptions drugs, which can increase the concentration of those medications in the body. There isn't much information out there about how long the effect of grapefruit juice lasts after it has been consumed. However, we do know that taking certain prescription drugs and grapefruit at the same time is a bad idea. (From the article below) "For example, simvastatin, when taken with about a 7-ounce glass of grapefruit juice once a day for three days, produced a 330% greater concentration of the drug compared to taking it with water"

http://www.medscape.com/viewarticle/775217?src=mpnews

Common prescription drugs that interact with grapefruit in this manner include:
-atorvastatin
-lovastatin
-simvastatin
-benzodiazepines
-cyclosporine
-estrogens
-sildenafil (viagra)
This is NOT an exhaustive list.   Additionally, grapefruit only has this effect on drugs that are taken orally.