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Soft drinks contribute to obesity problems

Question: I am a nurse and I work in a local hospital. Many of the nurses I work with buy the super-size soft drinks and drink from them most of the day. Many of these same nurses have a weight problem. Is there a relationship between drinking soft drinks and being overweight?

Answer: Soft drinks contain about 10 kilocalories (Kcals) to 12 Kcals per ounce, so a 48-ounce container would provide around 500 Kcals of energy. Since it takes only 3,500 Kcals to gain a pound of fat, drinking a 48-ounce soft drink would theoretically cause a one-pound increase in fat every seven days, or 52 pounds of fat every year.

Of course, in real life, very few people gain 52 pounds of fat a year, but the caloric load of drinking these large containers of pop is significant and could surely account for at least some of the weight gain experienced by those who drink lots of soda.

An interesting article related to soft drinks recently appeared in the medical journal Lancet. Researchers tracked 548 children ages 11 and 12 from public schools across Massachusetts for two school years. They found that an extra soft drink a day gave children a 60 percent greater chance of becoming obese, even when the type of food they ate, the amount of television they watched and physical activity were controlled.

The study also found that each sugared soft drink the children consumed each day increased their body mass index (a measurement of fatness) by 0.18 points.

Based on the theoretical caloric load and the research in this new study, I would cut out soft drinks if I were trying to lose extra body fat.

Question: Do the nose strips used by some athletes really help performance significantly? Some of my friends have begun to wear them when they exercise, and we decided to ask you if they really help. Thank you.

Answer: The idea of nose strips to help open the nasal passages sounds good because we all know how important oxygen is to the performance of aerobic activities such as jogging, cycling and cross-country skiing. However, science has not been able to prove that they help.

The February issue of Running&Fit News reported on a study in which 15 men and women were randomly assigned to either a placebo nose strip or an active nose strip and exercised to exhaustion on a bicycle ergometer. Measurements of performance, perception of effort and ventilation showed no advantage from the use of nose strips.

Although nasal dilator strips are known to decrease resistance to airflow and have been shown to help people with breathing while they sleep, athletic performance is a different matter. At rest you normally breathe mostly through your nose. But when you run (or work hard in any other activity), your air supply is delivered mostly through your mouth. Even more important, the lungs are not usually the limiting factor in aerobic work. Usually we are limited by either blood flow or the ability to use the oxygen at the muscle.

If you want to increase performance, you have to train more effectively to change the real limiting factors rather than use some crutch. Hope that helps.


Garth Fisher is director of the Human Performance Research Center at Brigham Young University.