"This also highlights the variability of calorie counts for similar meals," Urban said.
David Levitsky, a professor of nutrition and psychology at Cornell University in Ithaca, N.Y., said preparing your own meals at home slashes calorie consumption by 20 percent to 35 percent, simply because there is a tendency to serve yourself smaller portion sizes than are put before you when eating out.
"The amount of food and calories you consume per dollar is one of the major reasons you go back to that place," he said. "Restaurants know they are competing with other restaurants based on value, so they tend to be less concerned with your health and more concerned that you come back."
When faced with larger portion sizes, Levitsky said you almost always eat more because your brain is programmed to eat what's in front of you. It's a primal behavior based on bygone days when most humans weren't sure when they'd be eating again.
If eating at home isn't an option, Levitsky recommended ordering half portions, splitting an entree or asking the server to doggie bag half of your meal before it hits your plate.
Scourboutakos said it's also wise to skimp on sauces, dressings and extras and to surf the web for calorie counts when they are available before heading out to eat.