At what age do we stop being so active?

I wondered, at what point in our lives have we shifted from running to walking? From moving a lot to moving only if we need to? Basically, when does our moderate-to-vigorous activity level shift from the tireless running allover the place to the more adult-like style of moving when we need to? A very interesting study, published in the July 16, 2008 issue of JAMA gave some insight. The authors analyzed the data of more than 1000 children, almost half of them were boys and the other half were girls. The researchers followed their patterns of moderate-to-vigorous physical activity from age 9 to age 15. They found that at 9, the average child engaged in good 3 hours of moderate-to-vigorous physical activity, which is well more than the recommended minimum of 60 minutes per day. By age 15 years, adolescents were active at that level for only 49 minutes per weekday and 35 minutes per weekend day. Boys were more active than girls. It is well-known that decreased physical activity is an important factor in childhood obesity.

I am not sure what exactly happens. Why at some point in our lives we start walking if we don't have to run, and sit if we don't have to walk? At any rate, knowing that the transition takes place between the ages of 9 and 15, we can target that time interval and aim at keeping children engaged in organized moderate-to-vigorous activities during that period, hoping that the habit continues with them for so many more years of their lives.

Reference:

Nader PR, Bradley RH, Houts RM, McRitchie SL, O’Brien M.
Moderate-to-Vigorous Physical Activity From Ages 9 to 15 Years.
JAMA. 2008;300(3):295-305. (Abstract)

Affiliations of the authors of the reference article: Department of Pediatrics, University of California San Diego, La Jolla; Center for Applied Studies in Education, University of Arkansas, Little Rock; Statistics and Epidemiology, RTI International, Research Triangle Park, North Carolina; and Department of Human Development and Family Studies, University of North Carolina, Greensboro.

Childhood and Adolescent Obesity - A Real Concern

Well, this is another blog entry that is not a bariatric surgery issue, but a real public health and epidemiology concern. The New England Journal of Medicine issue of December 6, 2007, has three excellent articles:

1. Childhood Obesity — The Shape of Things to Come by Dr. D.S. Ludwig (Link) from Harvard Medicalo School
2. Childhood Body-Mass Index and the Risk of Coronary Heart Disease in Adulthood by Dr. J.L. Baker and others (Link) from Copenhagen, Denmark
3. Adolescent Overweight and Future Adult Coronary Heart Disease by Dr. K. Bibbins-Domingo and Others (Link) from the University of California, San Francisco

The Journal is making the full text of those articles (not just the abstracts) available for free.

In the perspective article "Childhood Obesity — The Shape of Things to Come", Dr. David Ludwig (Director of the Optimal Weight for Life Program, Children's Hospital Boston, Harvard Medical School) views the obesity epidemic as consisting of four phases. The first phase (began in the early 1970s) witnessed a progressive increase of the average weight among children from all socioeconomic levels and geographic areas in the United States.

The second phase, which we are now entering, is characterized by the emergence of serious weight-related problems in adolescents, including type 2 diabetes, fatty liver, orthopedic problems, sleep apnea, social isolation, anxiety, and depression.

Phase 3 will signal opening the doors for the medical complications of obesity to lead to life-threatening or limb-threatening disease. There will be an increased risk of coronary heart disease in adulthood, a high risk for limb amputation, kidney failure requiring dialysis, and premature death. The article quotes that the risk of dying by middle age is already two to three times as high among obese adolescent girls as it is among those of normal weight. Dr. Ludwig has predicted that pediatric obesity may shorten life expectancy in the United States by 2 to 5 years by midcentury, which would be equal to that of all cancers combined.

Phase 4 of the epidemic, if allowed to take place, will lead to even higher obesity rates because of transgenerational mechanisms.

Those articles are a highly recommended reading for anyone who feels that childhood obesity is hitting home.

Can TV ads influence our kids' taste buds?

This is not exactly a bariatric surgery topic, but, nevertheless, a very interesting one. Does advertising/branding affect children's taste? Well, we know that TV ads do influence kids, who, as a consequence, keep begging and nagging for an advertised product. The pressuring will intensify, once other parents provided your kids friends with the product. What standing do you have when you stick to the hated "No", while the attractive TV ads say "yes", and peers' parents have given the sign of approval?

A very interesting study came from Stanford Prevention Research Center and Stanford University School of Medicine. It was published in the August, 2007, issue of the "Archives of Pediatrics & Adolescent Medicine." (1) Kids aged 3-5 years (yes, that young!) were entered into a food tasting game, where they were given 2 identical food items, one wrapped in a McDonald's typical wrapping, and the other wrapped in a plane white wrapping. Items included not only hamburgers, fries and chicken McNugget's, but also baby carrots, which are not even sold at McDonald's, but were placed on top of a McDonald's french fries bag and on top of a matched plain white bag. McDonald's was chosen because it is a good example of a well-branded and heavily marketed source. Guess what? There was a statistically significant higher taste preference for the foods associated with the branded wrappings. This study is remarkable for its hypothesis, and the results that came out of it.

The authors concluded that branding of foods and beverages influences young children's taste perceptions. The authors also suggested that branding may be a useful strategy for improving young children's eating behaviors.

No wonder, a report of a joint "WHO/FAO Expert Consultation" indicated that: "Heavy marketing of fast-food outlets and energy-dense, micronutrient-poor foods and beverages" is a "probable" cause of excess weight gain and obesity. There has been strong evidence of a relationships between television viewing and obesity in children. Could that be, at least partially, due to the food advertising to which they are exposed? You bet.

(1) Robinson TN, Borzekowski DL, Matheson DM, Kraemer HC. Effects of fast food branding on young children's taste preferences. Arch Pediatr Adolesc Med. 2007 Aug;161(8):792-7. PMID: 17679662