Remember the Grapefruit Diet from way back that had us eating the
citrus fruit at breakfast, lunch, and dinner? That plan may have been
just a kooky fad, but new research shows grapefruit is actually a
powerful diet food.
A review of data from 2003 to 2008 reveals that, on average, women
who consumed any amount of grapefruit or grapefruit juice weighed nearly
10 pounds less and had a 6 percent lower body mass index (BMI) than
their non-grapefruit-eating counterparts.
Researchers aren’t exactly sure what makes grapefruit lovers slimmer,
but study co-author Gail Rampersaud, RD, of the University of Florida,
says it could be the simplest of reasons: “Consuming fruits and
vegetables with a high water content, like grapefruit, helps you feel
fuller and more satisfied on fewer calories.” (Half of a medium
grapefruit or an 8-ounce glass of juice has fewer than 100 cals each.)
The fruit is also a source of vitamin C, potassium, and magnesium,
but Rampersaud says there’s no evidence revealing any magical
fat-burning ingredient at work, as proponents of the old Grapefruit Diet
have claimed.
To reap the benefits, Rampersaud suggests making the tart and tangy fruit or juice part of your daily diet.
Not a grapefruit lover? Based on this and other studies, starting
meals with water-rich foods, such as cucumber or watermelon, could have a
similar effect, says Christine Gerbstadt, MD, RD, spokesperson for the
Academy of Nutrition and Dietetics.........
source
Yeah, dairy has a bad rep for high calories, but
yogurt, both the low-fat and regular kinds, contains probiotics:
"friendly" bacteria that preliminary research suggests may actually help reduce the amount of fat your body absorbs. 
Again, the caffeine kicks your metabolism into
high gear. Caffeine also jump-starts lipolysis, the breakdown of fat.
One to two cups a day is ideal. 
