Dieting can be a real challenge, especially if you're always on the go. But "Extra's" celebrity diet coach Jorge Cruise is sharing his ultimate diet secrets for people living in the fast food lane.

Celebrities like Britney Spears and even the Governator can't get enough of Tinseltown's quick fix: In-N-Out Burger. So Cruise explained to us that you can eat fast food and still stay fit, losing up to two pounds a week.

"Today you don't have to be a slave to high-fat, high-calorie foods," he insisted. "Eating small meals on the go every three hours, you do that and you're going to lose belly fat first."

With his 3-Hour Diet, Cruise provides an on-the-go guide to the Fit Choice versus the Fat Choice:

Breakfast
If you're in a rush in the a.m., you may pop by McDonalds, thinking that your diet is now out the window. But think again….

The Fit Choice for breakfast can be an Egg McMuffin, sliced apples and coffee, which amounts to less than 400 calories.

Compare that to the fat choice: Hotcakes, sausage, hash browns and orange juice, which comes out to almost 1,200 calories. The Fit Choice saves you about 800 calories.

Lunch
"Believe it not," Cruise told us. "You can stick to your diet and eat at Burger King."

For lunch, the Fit Choice is a Whopper Junior, a side salad and diet soda for a total of 380 calories.

The Fat Choice amounts to nearly 2,000 calories, including a Double Whopper with cheese, large fries and a large cola.

Dinner
"Dinner time is in the bag," Cruise insisted. "Subway has tons of no-guilt choices."

The Fit Choice includes a turkey sub, a side salad and diet soda, which is only 375 calories. The Fat Choice, however, can be around 1,020 calories with a chicken parmesan sub.

So now, thanks to Jorge, you can lose weight fast and still eat fast food!