Bad news, ladies: According to a new report from the U.S. Centers for Disease Control and Prevention, 42 percent of Americans will be obese by 2030, meaning you could look (and feel) very different 18 years from now.About two-thirds of Americans are currently overweight and about 34 percent of adults are obese — and fitting into their skinny jeans is the least of their problems. Obesity has been linked to an increased risk of cardiovascular disease, diabetes and certain types of cancer, among other health issues. Plus, the report also predicts that in 2030, 11 percent of Americans will be severely obese, defined as more than 100 pounds overweight.MORE FROM SELF: The Top 10 Best SuperfoodsSo what can you do NOW to make sure this doesn’t happen to you? We asked SELF contributing editors Stephanie Clarke and Willow Jarosh, registered dietitians and co-founders of C&J Nutrition, how you can stay healthy, slim and sexy well into 2030 and beyond. Here are four of their super-easy tips:1. Do something — anything — now. Often, the enormity of changing habits that we’ve acquired over a long period of time can be so daunting that we put off doing anything at all.  Pick one small change that you can make today, and continue doing it until it’s a habit. Then, move on to the next thing.2. Don’t drink your calories. Research shows that liquid calories don’t make us feel satisfied the way that calories from solid foods do. If you’re a regular soda drinker, drinking a 12 oz can of soda each day in addition to your regular diet is the equivalent of 14 pounds over the course of a year. Think of soda, as well as sweetened teas and lemonades, as a treat. Use water (flat or sparkling) as your daily thirst-quenching drink. To help make the transition easier, start by replacing half of your daily soda intake with sparkling water mixed with 1-2 ounces of fruit juice.  Then, gradually work your way toward replacing all of it with water.MORE FROM SELF: Drop 10 Pounds (or More!)3. Create a network of friends and family members who value living a healthy lifestyle. Arrange many of your social gatherings around active events like charity runs/walks; group hikes, walks, runs and bikes; intramural sporting events; and/or group exercise classes. By doing this, you will meet and surround yourself with people who are also interested in staying healthy, making you more likely to do the same in the long term.4. Learn to cook. You don’t have to be a Le Cordon Bleu-trained chef, but knowing how to prepare basic healthful meals at home is key to eating right on a regular basis. Restaurant portions are typically much too large; packed with excess calories, fat and sodium; and pricey, too. Learning to cook is not only important for you, it can also help prevent obesity in your whole household (your roommate/boyfriend/spouse/child will thank you). Plus, it’s fun!MORE FROM SELF: 5 Minutes to Flat Abs