As neurologist David Perlmutter examines patient Lauren Essex, it's hard to believe her now smiling eyes were once blinded by crippling migraines.
Perlmutter put Essex on a diet that's now made him a best selling author. His books call for more of something most people try to avoid -- Fat!
"We're desperate for fat, our immune systems require fat, every cell in your body is made up of a lot of fat, and your brain is more than 60 percent fat," Perlmutter said.
So Essex cranked up her fat intake and the migraines went away. But the headaches weren't the only thing that disappeared.
Essex said you start losing your belly fat almost immediately.
"It is a high fat diet that will only work if you cut the carbs," Perlmutter said. "So as long as you're eating high fat and still have a lot of carbs in your diet, you're going to stimulate insulin which signals your body to retain fat, and generate new fat and locks up your current fat and doesn't allow you break it down to use as calories."
As for eggs, known for their saturated fat and cholesterol content, the doctor says eat up -- especially the yokes.
"When you eat cholesterol it turns down the mechanism in you body that makes cholesterol, so eat eggs. But they should be pasture raised eggs," Perlmutter said.
Essex said the changes to her diet have changed her health and her life.
Perlmutter promises it can be just as exciting for you -- to let that three letter word to work its magic.
"When you eat fat, again, it tells your body calorie sources are plentiful, it means you've got good sources of food and it sends a signal to your body we don't need to store fat," he said.
Another tip -- don't overdo it on fruit. Perlmutter said fruit is pure carbs, and too much can lead to weight gain.