If you're a fan of croissants, buttery grilled cheese sandwiches, and dairy-soaked mashed potatoes, you might want to think again. It could be time to give up butter and other dairy fats to promote better health.

A study published in JAMA Internal Medicine looked at 30 years' worth of data on 200,000 people and concluded that substituting canola, olive, and soybean oils for around a tablespoon of butter a day lowers the risk of death from cancer and cardiovascular disease by about 17%.

And just think what giving up all butter can do for your happy health span.

If that's not enough of an incentive, a recent lab study indicates that even a few days of eating a high-fat diet is enough to cause brain inflammation and memory problems (especially in older people).

You might not be aware of how fat-loaded foods are. For example, 60% of the calories in a McDonald's double smoky BLT quarter pounder with cheese or a Burger King double Whopper with cheese come from fat — a lot of it saturated fats.

But eating lots of foods fried in vegetable oils is not good for your health either. That can overload your system with inflammatory omega-6 fatty acids, and heated vegetable oils can form trans fats that increase your risk for heart disease, obesity, dementia, and diabetes.

To discover how eliminating saturated fats and fried foods from your diet can transform your tomorrows, check out the book "YOU: On a Diet."