From a list of ten possible causes of weight gain – ones experts feel play a role in the obesiy epidemic – I asked the teens to chec off the five main reasons for their weight gain. At least 75% cited the first three causes; each of the other causes was checked by at least 25% of the teens. No teen gave just one reason for weight gain; some checked them all. Here’s how the reasons rank, according to how often they were checked.

Reason #1: Too much snacking. Molly S feels that oversnacking was the number one cause of her weight gain. Now, her mother says, “we have nothing very snack food related in the cupboard. Ice cream, cookies, chips, et cetera, have been replaced by fruits.”

Reason #2: Portion sizes too large. Erin D says that her portions were three times larger when she was overweight than they are today. “Now,” she says, “when I go to fast-food restaurants, I can’t eat a whole value meal. I’m satisfied with a kid’s meal.”

Reason #3: Not enough exercise. Victor F was able to lose 50 pounds by exercising four or five times a week, as well as by learning about and practicing good nutrition. Three years later, he still finds time to exercise regularly, even though he’s in medical school.

Reason #4: Ate too many sweets and desserts: Wes G, who feels that his number one reason for gaining weight was eating too many sugary foods, says that a major difference for him now is cutting out his nightly “giant bowl of ice cream.” (He still eats occasionally.)

Reason #5: Emotional causes (eating when lonely, bored, or sad). Sari M became overweight when her father left the family. Now when she feels like eating for emotional reasons, she usually goes to a coffee house, “where the drinks are all fairly low calorie and I can be around people and friends who will hopefully cheer me up.”

Reason #6: Spent too much time in front of the TF, computer, and/or video games. Christine F says that too much TV and computer time were the major culprits in her weight gain. The most important thing she did to lose weight was “exercised! It took a while to get motivated, but as soon as there were visible results, I was hooked.”

Reason #7: At too much fast food. Mick J told me, “Throughout middle school, I have memories of my mom bringing me a McDonald’s dinner every day after school.” Now he eats “very little fast food” and says, “I haven’t set foot in a McDonald’s since 1999.”

Reason #8: It runs in my family. With two parents and several other family members who were obese, Victoria H feels that genetics were the number once cause of her weight problem. She once weighed close to 500 pounds but has been able to lose and keep off at least 250 pounds for about 7 years. Although she is still heavier than she’d like to be, Victoria is realistic about her weight goal because of her family history.

Reason #9: Drank too much soda. Ally S sees this as the number one cause of her weight problem. When asked to describe the most important thing she did to lose weight, she replied, “I stopped drinking soda and sugar beverages. Now I only drink milk and water.”

Reason #10: Too many fattening foods served at home. This was on Sandra D’s list of culprits. She says, “My parents struggle with their own weight, so their examples were not in my best interest. I’ve lost a lot of weight because of the choices I’ve made, not because of their influence. However, they do drive me to the gym and buy healthy foods for me.”