Maybe a little, if you substitute it for other vegetable oils. This new cooking and salad oil is a blend of heart-healthy canola and soybean oils, which have been chemically altered. While other oils are made mostly of fat molecules called triglycerides, Enova oil consists primarily of diglycerides. The oil is "generally recognized as safe" by the FDA and has been used in Japan since 1999 with no known problems. It may soon be used in some processed foods, including spreads, mayonnaise, and baked goods.

Not a fat substitute like olestra, Enova oil has a taste and nutritional profile (120 calories, 14 grams of fat per tablespoon) similar to regular vegetable oils, and is absorbed and broken down in the body just like other fats. But because of its structural difference, more of it is burned in the liver as energy; less is stored as fat.

Research, however, is limited. In a six-month study from the Chicago Center for Clinical Research of 79 obese men and women on reduced-calorie diets, those who consumed 15% of their calories from Enova oil (two to three tablespoons a day) lost about two more pounds than people consuming an equivalent amount of regular oils. Some research suggests that Enova oil may also help control appetite and temporarily lower triglycerides in the blood.

Bottom line: Enova oil may have a small effect on body weight--but only if you use it in place of other vegetable oils, not in addition to them, and only if you reduce your overall calories. Eat too much of this or any oil and you'll gain weight. Enova oil costs more than most other vegetable oils--about $5 for 20 ounces.