SAN ANTONIO EXPRESS-NEWS Midnight pizza pig-outs, frat parties, the freedom to play video games into the wee hours -- college students face a lot of temptations when they're on their own for the first time. Now's the time to talk to teens about making healthy choices once they've left the nest. Here are some of the top health issues for college students: Sexual health: There are approximately 19 million new cases of sexually transmitted diseases each year in the U.S., according to the Centers for Disease Control and Prevention (CDC), and nearly half of them are among people ages 15 to 24. If students are having sex, they should be prepared. They need to 'have condoms and know how to use them,' said Mark Macias, health education coordinator for the University of Texas at San Antonio. The CDC recommends that women 26 or younger get an HPV vaccine to help prevent cervical cancer. Sexually active men and women should also be tested routinely for STDs. Alcohol: Binge drinking remains a problem on many college campuses, but Macias says it's important for students to know that the 'Animal House' mentality isn't the norm, and it's possible to have fun without alcohol. Drinking excessively can cause alcohol poisoning, injuries, assaults and unsafe sex among college students. Underage students shouldn't be drinking at all, but even those who can drink legally should follow a few rules, according to the American Council on Alcoholism, including drinking in moderation and on a full stomach, not accepting drinks they haven't seen prepared and choosing a designated driver. Weight control: All-you-can-eat dining halls and late-night pizza-and-sub runs can pile on the pounds. Research published in Nutrition Journal shows 23 percent of freshmen gain at least five percent of their body weight, an average of about 10 pounds, during their first semester at school. The American Council on Exercise advises freshmen to stick to a regular meal schedule (no skipping breakfast), stock up on produce and other health snacks and limit alcohol, which often contain hundreds of empty calories and can trigger hunger. Students should take advantage of campus recreation centers and intramural sports offered through the school, say ACE experts, and consider enrolling in a nutrition class or fitness class for credit. Bonus: Hitting the gym helps relieve the stress brought on by loads of schoolwork and promotes better sleep. Sleep: Pulling all-nighters -- either to study or to party -- can take its toll. Adults need about seven to nine hours of sleep every night, according to the National Sleep Foundation; getting too little can make it harder to pay attention in class and remember new information. Students -- like anyone else -- should maintain a regular sleep schedule, even on weekends. Consuming caffeine, alcohol and food too close to bedtime can disrupt sleep. 