Trans fat is out, but good fats are in

“‘Fat-free' used to mean healthy, but now we know that's totally wrong” said Minh-Hai Tran, a registered dietitian in private practice in Seattle.

While certain lipids, such as trans fats, are still known to be bad for us (and probably always will be), it’s not a good idea to lump all fats together into one group, Tran said. Numerous studies have shown that the omega-3 fatty acids found in fish and fish oil supplements promote heart and brain health, and a 2009 study in the journal BMC Cancer found they also lower the risk of breast cancer in post-menopausal women.

Omega-3s, which also have been found to improve conditions such as arthritis, high cholesterol and attention disorders, are found in many grains, seeds and nuts as well.