Screen time includes TV viewing, recreational use of the computer, videos, video games and any other device used for sedentary games or entertainment. There is widespread agreement that too much screen time leads to increases in body fat ^1-5 and reducing screen time leads to fat loss.^6,7 Most studies of this issue have found positive associations—the more screen time, the higher the weight, body mass index (BMI) or body fat. Is it because food intake is increased, physical activity is decreased, or both? To better understand the mechanism by which screen time is linked to obesity, scientists have hypothesized that increased body fatness occurs in one or more ways:

1. Displacement of physical activity.¹ As screen viewing time increases, less time is left in the day to be active, so total daily physical activity is reduced.
2. Reduction of outdoor play. ⁸ Screen time viewing occurs indoors. Since being outdoors is associated with increased physical activity, excessive screen time leads to reduced physical activity, a consequence of remaining indoors for too long.
3. Increased food consumption.^9-12 Food advertising on TV and other media leads to eating more food during or after TV viewing.
4. Increased consumption of energy dense or "junk" foods. ^4,13-16 Food advertising in the media is predominantly for energy dense foods, meaning foods that are low in fiber and high in calories, sugar and fat. The ads stimulate demand for more energy dense foods, which leads to excess calorie intake.
5. Distraction from internal cues that promote self-monitoring.^13,17-19 Internal physiological cues that regulate food intake are either not sensed or are ignored. The screen distracts you from being mindful of these cues and leads to mindless eating or snacking.
6. Emotional reactivity that elicits an eating response.^12,15,20 Program content that is either negative (sad or scary) or positive (heart warming) creates an emotional state that is accompanied by or followed by eating. This responsiveness may vary with body weight, obesity or dietary restraint* status.

The quality of evidence supporting these possible explanations, including the duration of the studies, participants' weight status, age, gender, and prior experience eating with or without the TV on varied widely, so none of these effects of screen time on obesity can be ruled out at this time.

In this field of very active research, one study stands out because the researchers used state-of-the-art techniques to measure total daily energy expenditure (doubly labeled water), body composition including body fat (dual-energy X-ray absorptiometry) and physical activity (accelerometry).²¹ In this Scottish study of 2 to 6 year olds, each extra hour a child spent watching TV was associated with an increase of about 1 kilogram (2.2 pounds) in body fatness. In an analysis of the data, the authors concluded that the increased body fatness was explained by increased food intake rather than by decreased physical activity. These findings do not agree with another study in the same age group, which concluded that TV viewing and physical activity, and not diet, predicted BMI over time.²² However, the methodology used by the former study to measure energy expenditure, physical activity and body composition is preferable.

In conclusion, screen time has been linked to increased body fatness in children and adults. In adults, time spent watching TV has been associated with an increased occurrence of type 2 diabetes.⁵ One group of researchers concluded that in women, restricting TV watching to less than 10 hours per week and increasing brisk walking to 30 minutes or more each day would reduce new cases of obesity by about one-third and new cases of type 2 diabetes by up to one-half.⁵ So for good health and a trimmer waistline, turn off the TV. Limit recreational screen time to no more than two hours a day, and aim to go screen free two or more days each week.

*Dietary restraint is a measure of the extent to which an individual consciously restricts or limits food intake. Individuals are classified as either restrained or unrestrained eaters.

Core exercises are not complicated and don't require the use of specialized equipment. But if you are interested in developing overall strength, muscle tone, and endurance in these various muscle groups, it is important to target several muscles. Many people perform basic abdominal exercises that only focus on strengthening the rectus abdominus—the long, flat muscle in the front of your abdominal region.

One exercise for developing the rectus abdominus is the bicycle crunch exercise. To perform, lie on the ground with your back pressed into the floor. Place your fingertips beside your ears, bringing your knees up and moving in a bicycle pedaling motion, trying to touch your right elbow to left knee, and alternating sides, breathing evenly throughout the movement. Aim for three sets of 10 to 20 repetitions.

Though an important muscle, focusing only on development of the rectus abdominus places too much emphasis on the "six pack" development and not enough on the "weight belt" of the abdominal wall, the transverse abdominus. Though a "six pack" looks great, it doesn't improve body alignment or enhance movement.

Including exercise that develops the transverse abdominus ensures movement safety when you perform activities on a stable surface. This dominant muscle assists the body in maintaining stability during activities such as trunk rotation during lifting, and it helps to safely support the body during movement. One simple abdominal exercise for developing the transverse abdominus is to sit on a bench and place one hand on your belly button. Keeping your spine in a neutral position, concentrate on contracting your transverse abdominus by internally pulling your belly button up into your spine. Work up to three sets of 10 to 20 repetitions. You can practice this exercise in many everyday situations, fitting in some quality muscle development while doing other things. By training this muscular belt on the inside, you will be tightening your belt on the outside!

It is important to develop back strength in order to balance strength development of the core in the front and back of the body. An important group of muscles in the back of your core is the erector spinae muscles, which support your back from your neck to your lower back. A great exercise for developing strength in these three muscles is the back extension. To do this exercise, lie face down on the floor with fingertips behind the ears. Contract your abdominal muscles and lift your chest a few inches off the floor, slowly returning to the start position. You may need to start out by doing far less, but aim to work up slowly (over a period of weeks or even months) to the goal of repeating this exercise for three sets of 10 to 20 repetitions.

Incorporating training of these three muscle groups into your regular exercise regimen will enhance core muscle development and ensure your safety during many types of dynamic movement.

Pre-registration is required. Location details, meeting time and fee can be found here. Or call (212) 305-3334.

The Summit will consist of two distinct programs: The two-day Clinical Practice-Focused Program will discuss evidence-based research findings, prevention approaches, and management strategies for obesity. Topics will include childhood obesity, women's obesity issues, pharmacologic strategies, and new nonsurgical procedures. The half-day Industry-Focused Program will discuss innovations and new directions for therapeutic modalities. More information is available at here.

Bok Choy with Portobello and Tofu
Makes 2 servings

INGREDIENTS:

• 1 Tbsp. canola or sesame oil
• ½ package of firm tofu, cubed
• 2 stalks celery, chopped
• 1½ cups (1/2 pound) Portobello mushrooms, chopped
• 3 cups bok choy, chopped
• 1 Tbsp. miso
• ½ cup low sodium vegetable stock
• 1 tsp. fresh ginger, grated
• 1 garlic clove, minced
• 1 Tbsp. low sodium soy sauce
• 3 green onions, chopped
• 2 cups fresh spinach, chopped
• 2 cups cooked rice

DIRECTIONS:

1. Heat oil over medium heat. Add tofu, celery and mushrooms. Sauté until tofu begins to color, about 5 minutes.
2. Place the bok choy on top. Lower heat to medium-low and cover. Cook about 10 minutes.
3. Whisk together miso, vegetable stock, ginger, garlic and soy sauce. Pour over bok choy and stir.
4. Add onions and spinach on top. Cover again and cook for about 5 minutes.
5. Stir well and serve with rice.

Nutritional analysis per serving (including rice): 400 calories, 9 grams total fat, 0.5 gram saturated fat, 58 grams carbohydrate, 12 grams protein, 7 grams dietary fiber, 770 milligrams sodium.

Source: American Institute for Cancer Research