Why your still hungry after some meals

If you're still hungry after some meals, blame this particular fat.

That fatty bacon cheeseburger may be loaded with calories, but at least it stomps out your hunger. Right?

Not necessarily. Compared to low-fat meals with the same number of calories, meals that are basically fat fiestas do an odd thing: The saturated fats in them make your body release less leptin, a hormone designed to turn off appetite. Saturated fats are the belly-bulgers and artery-agers found in fats that come from four-legged sources: high-fat red meats, butter, full-fat cheeses and other whole-milk products. (Trans fats are just as bad, by the way.) Sat fats are rarely found in plant foods, with two vital exceptions: palm and coconut oils.

To help your body release leptin, which is stored in fat cells (See? You knew they were good for something.), you need to eat healthful unsaturated fats. Find them in nuts (especially walnuts), seeds, olives, avocados, most vegetable oils (especially canola), many fish and even algae (or DHA omega-3 supplements made from algae). You don't want to avoid fat altogether: You need it to maintain your energy, absorb certain nutrients, and repair tissue. And moderate amounts of healthy fat are associated with a decreased risk of heart disease.

You also want to help leptin do its No. 1 job: Telling you, "You're not hungry anymore." So in addition to avoiding sat fat, adopt these waist protectors:

• Watch your alcohol intake. It inhibits leptin, even as it disinhibits dancing on the table or phoning your ex.

• Walk 30 minutes every day and build a little muscle. Sometimes, leptin doesn't work the way it's supposed to and your cells stop responding to its messages. When you trim down, your cells become more sensitive to leptin again.