Dieting? Don't fear the fat.

If you're watching your weight and hoping it will go down, the best thing to do is not avoid fat. Fats actually help with weight loss because of satiety.

So is everything we've learned about fats for the past 30 years wrong? Well, kind of. Sophisticated fat analyzing technology has shown that what we once thought were good fats - like margarine, a hydrogenated trans fat made from vegetable oil - are actually bad. Conversely, fats we thought were "bad," namely, lard, dairy fats, and palm oil, are actually good.

The thinking now is that you should include a reasonable amount of healthy saturated fats at each meal because they supply the building blocks for how we function as humans, make up the structure of our cells, carry essential vitamins, help fabricate hormones, and provide protective padding for our organs. The brain and body require fat to develop and grow optimally, even in adulthood. Fats also improve the immune system and contribute to bone health.

And they provide satiety. You might feel quite satisfied, for instance, if you crumble two slices of crisp bacon and one ounce of cheese on your salad or eat that delectable golden skin on your broiled chicken. No one is advising you to eat mountains of fries or other foods made with commercially processed fats. The suggestion is a judicious amount (about 1 tablespoon per meal) of naturally occurring fats. Think of butter, cheese, chicken or duck fat, even well-marbled steaks, as a taste-enhancing complement to a meal.

Some experts say otherwise. The USDA dietary guidelines recommend Americans reduce fat in their diet, especially saturated fat. And health magazines, especially this time of year, encourage readers to limit their intake of fats from dairy products and meat.

But a 2008 study from the Albert Einstein College of Medicine published in the American Journal of Preventive Medicine argues that widespread guidelines against dietary fat may have led to our current obesity epidemic. The report evaluates 30 years of US dietary habits and concludes that as Americans followed recommended fat-reduction guidelines, they ate more calories from sugar and carbs and gained weight.

New knowledge also reveals animal fats may be beneficial to our health. "We make use of and metabolize animal fats in ways not previously understood," says Dale E. Bauman, a professor of nutritional biochemistry at Cornell University. Bauman is convinced today's science supports the concept that fats from a ruminant (cow, goat, sheep) provide valuable nutrients that help maintain health and prevent disease.

Enjoying fat and feeling OK about it may seem like a new idea, but humans have been eating fat for a lot longer than they've been abstaining. Animal fat has passed evolution's test.

Science may just be catching up.