Compared to 10 years ago, has your screen time - the time you spend watching TV, using a computer, and checking your smartphone - increased?

Unless you're a hermit, how do you answer "no" to that? Take my case, for example. My TV cannot digitally record or even play DVD's, I don't own a smartphone, yet by doing so much more referencing, researching, shopping, and bill paying on my laptop via the Internet, I've probably increased my screen time in the last decade by 30 percent.I have, however, managed to avoid a second increase linked to increased screen time: an increased waistline.Maybe you haven't been so fortunate. At least, that's the national trend.Dr. Graham A. Colditz and Lin Yang, of the Washington University School of Medicine in St. Louis, have crunched the numbers provided from the last five-year National Health and Nutrition Examination Survey and determined that the nation's collective weight has increased since the last such survey about 20 years ago.Based on the body mass index of more than 15,000 Americans aged 25 and above, Colditz and Yang estimate that two out of every three adult American females and three out of every four adult American males are now overweight or obese.As you well know, a big belly does more than detract from your appearance. It also increases the likelihood that you'll develop an abundance of afflictions, with type 2 diabetes, heart disease, and stroke being three of the worst.But what you may not know as well is the extra weight stresses the health care system. In 2013, for instance, the American Heart Association calculated the cost of weight-related medical bills in the United States at $190 billion a year.Something else you may not know as well: an effective way to "whittle" away your waistline.The word "whittle" is used in this article intentionally for it connotes more than just "reducing." It suggests more of a hands-on action, like paring, trimming, shaping, or carving.Since you can't really spot reduce fat, you might feel that this word choice is inappropriate, but consider this: if you do nothing more than diet to reduce your body weight, you won't change your shape. You'll just reduce your dimensions.That's why it's best to "whittle" away while losing weight, and that's why today's column will begin a three-point plan to do that:1) Eat in such a way to burn body fat;2) Exercise intensely enough to burn body fat;3) Lift weights.Eat in such a way to burn body fatWhether you want your "whittling" to eventually carve out six-pack abs or pare down a less-than-pleasing paunch, you have to eat fewer calories than you're eating presently. But there's far more to the process of optimally burning body fat than following the typical bestsellers' list diet.The composition of the calories you do eat, the times you choose to eat them, and the degree of your caloric cutback commingle and ultimately determine to what degree you burn body fat.Your body prefers to run on energy that comes from carbohydrates, which is why you often crave simple ones. It's your body's fuel of choice found in a form that energizes fast, since the fewer chemical bonds found in simple carbohydrates like table sugar, sugar-sweetened beverages, white bread, and typical pasta allow for quick digestion.But quick digestion of carbs counteracts the burning of body fat.Only when your body lacks or perceives a lack of carbs (called glucose in the blood stream and glycogen when stored in muscles), does it burn an appreciable amount of body fat. That's why first-thing-in the morning exercise does a better job of tapping into the fat stores than the same dose of exercise after breakfast, lunch or supper.And it's also why so many athletes avoid eating three hours before a competition or an important workout. After eating, it takes three hours for blood sugar to drop to fasting levels. Because of a relative lack of blood sugar at this time, your body burns a higher percentage of fat to fuel exercise.Yet too dramatic a cutback in overall calories keeps the body from burning body fat. Instead, the body shifts into survival mode, and you catabolize muscle and conserve body fat to.That shift to survival mode is why diets that limit you to 1000 or 800 or even 600 calories create both an immediate weight-loss and an eventual weight gain. A body stripped of 10 pounds of fat at the expense of five pounds of muscle becomes a body that requires significantly fewer calories per day.To be sure to keep your body from shifting into survival mode while dieting, reduce your calories by about 350 per day. That's really not much: about a can of sugar-sweetened soda, a dozen potato chips, and a big bite of bakery-made chocolate chip cookie.While this moderate reduction promotes body fat loss rather than overall body weight loss, it does so at a slower rate than the typical bestsellers' list diet book.The focus of next week's column, the second and third points in the whittle-away-your-waistline plan, however, can accelerate the rate, so that you'll see an appreciable difference in a month or so.