Michelle Edelbaum

I think we all have one of these friends: she's thin and fit, yet when we go out to eat she packs away more food than a linebacker. Burger, fries and a shake? No problem. I'm often tempted to keep up: if she can eat it and look that good, I can too, right? (Look better in 4 weeks with our super-easy plan to slim down.)

Not so fast, I tell myself, remembering what I read in our latest issue of EatingWell Magazine. A recent study in the Journal of Consumer Research found that female college students who watched a film alongside a researcher who was thin ended up eating almost twice as much as when they ate alongside the same researcher wearing a fat suit to make her look obese. (Find 3 foods to eat when you overeat here.)

There are several reasons why I may not be able to keep up with my friend and expect the same results, according to the researcher, Brent McFerran, Ph.D.: metabolism, body size, genetics, activity level, age and gender all affect how much one can consume without gaining weight. (Get three simple tricks to outsmart your metabolism here.) Those factors aside, consider that my friend maybe didn't eat a large breakfast or for her this big meal is a rare treat. (Discover 5 "bad" foods you should be eating.)

So instead of telling the waiter, "I'll have what she's having," I'm going to remember to keep my eyes on my own plate, and order a meal that's healthy for me. Or better yet, I'll invite my favorite friends over for dinner and cook them a delicious, healthy meal we can all enjoy. (Get some easy dinner recipes ready in 30 minutes here.)

Michelle is the digital director for EatingWell. She puts her background in journalism to work at EatingWell.com to help deliver daily inspiration for eating healthy.