Archive for September, 2012

Obesity is a Military Readiness Problem

September 28th, 2012

Mission: Readiness, a non-profit organization of some 200 former senior military officers, has issued its report, “Still Too Fat to Fight,” an update of its 2010 report.  The report notes that 1 in 4 American adults of military service age are ineligible because of body weight. The report calls for additional efforts to remove junk food from schools. See http://missionreadiness.s3.amazonaws.com/wp-content/uploads/Still-Too-Fat-To-Fight-Report.pdf

Additional ammo for appreciating the gravity of the obesity epidemic for the US military comes from two papers by John Cawley and Johanna Catherine MacLean,  of Cornell University and University of Pennsylvania, respectively.

In their article, “Unfit for Service: the implications of rising obesity for US military recruitment,” the authors document the fraction of age-eligible civilians exceeding the weight and body fat standards for the US Army.  They find that the percentage of military age adults ineligible for enlistment because they are overweight or over-fat more than doubled for men and tripled for women from 1959 to 2008. They further estimate that a rise of just 1% in weight and body fat would further reduce eligibility by over 850,000 men and 1.3 million women, posing a major challenge for defense policy-makers. PubMed: Unfit for Serivce

In another article coming out in December 2012 issue of the journal, Applied Economic Perspectives and Policy, they address the consequences of rising youth obesity for US military academy admissions. They found that the fraction of age-eligible civilians exceeding the standards for admission to the US Military Academy at West Point, the US Naval Academy at Annapolis and the US Air Force Academy in Colorado Springs, CO, has more than doubled for men and quadrupled for women between 1959 and 2010. Among women, it is 13% more likely that African-American will not meet the standards than white women. Further increases of just 1% in the civilian obesity rate will increase ineligibility 16.5% for men and 10.9% for women. Not only do these findings threaten the military’s drive to greater diversity in its officer corps, but they may reduce US military readiness as well.

The obesity problem does not end with military service A recent study by Littman and colleagues at the VA Puget Sound Health Care System, found that weight gain was greatest around the time of discharge from service and in the 3 years prior to discharge. Being younger, less educated, overweight and have combat experience were all associated with clinically significant weight gain. This identifies a window which accounts for higher rates of obesity in veterans. PubMed: Weight Change following US military service

 

Physical Activity Interventions for Children Not Successful

September 28th, 2012

According to a just published meta-analysis in the British Medical Journal, “Physical activity interventions have little effect on the overall activity levels of children, which may explain, at least in part why such interventions have a limited effect on body mass index or body fat. The outcome of this meta-analysis questions the contribution of physical activity to the prevention of childhood obesity.”

The meta-analysis included 30 studies involving 14,326 participants, 6,153 with accelerometer measurements. The pooled results provided strong evidence that physical activity interventions have only a small effect (approximately 4 minutes more walking or running per day) on children’s overall activity levels, explaining why such interventions have limited success in reducing body mass index or body fat in children. After school activity may simply replace other activities the child would be normally engaging in or the child may compensate for the exercise by eating back many or most of the calories expended. BMJ: Effectiveness of intervention on physical activity of children

 

Note to Mayor Bloomberg: It’s Harder than you think

September 27th, 2012

On September 13, 2012, the New York City Board of Health enacted Mayor Michael Bloomberg’s proposal to limit the size of cups selling soda in New York City. The soda cup size ban over 16 oz only for facilities subject to inspection: restaurants, movie theatres, and stadium concession stands. Not covered are convenience stands, including 7-Elelven’s  (and its king-size Big Gulp drinks), vending machines and some newsstands. Also not affected are fruit juices, dairy-based  drinks like milkshakes or alcoholic beverages and non-caloric beverages. Fast food restaurants with self-service drink fountains would not be allowed to stock cups larger than 16 ounces. http://www.nytimes.com/2012/09/14/nyregion/health-board-approves-bloombergs-soda-ban.html.

There is no ban on  buying  two under 16oz cups of soda, selling ‘two for the price of one’, or free re-fills.

While most anti-obesity advocates shudder at the thought of sugar sweetened beverages, there is doubt over whether a ban on the size of the cup in which they are delivered is going to have much impact. Here’s why.

  1. Most sugar sweetened beverages (SSBs) are consumed by teenage boys, especially low income African-American and Hispanic. The ban rests on a hope that the consumers will voluntary switch from SSBs to some non- or low-caloric beverage. Yet, there is no educational campaign or subsidy to get them to substitute an SSB for another no/low-calorie drink. http://www.cdc.gov/nchs/data/databriefs/db71.pdf
  2. Males consume an average of 178 kcal from ssbs on any given day. Among males 12-19, consumption is highest at 273 kcal a day. This is still only a small  fraction of their total daily caloric intake. http://www.cdc.gov/nchs/data/databriefs/db71.pdf

At 273 kcal a day, a person would put on about 28 pounds a year. This is not happening, so the caloric intake is probably balanced to a large, if not full extent, by energy expenditure. The CARDIA study of 18-30 African-American and white men  and women   found that physical fitness changes were most strongly associated with weight changes over 7 years. Weight changes in this study range from 5.2kg in white women to 8.5 in African-American women.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1380845/pdf/amjph00503-0109.pdf

  1. Over half of sugar drink kilocalories, 52%, are consumed in the home, 92% having been purchased in stores. Presumably, the store-bought items are in cans and bottles, not in the cup sizes subject to the NYC ban. Of the 48% of kcal consumed away from home, 35.5% are purchased in fast-food restaurants and 1.4% in schools or daycare settings. 20% are consumed in vending machines, cafeterias, street vendors and community food programs. So, only about 1/3 of sugar drink consumption is in restaurants or fast-food outlets.   http://www.cdc.gov/nchs/data/databriefs/db71.pdf
  1. SSBs, while associated with increased daily caloric intake, are not the leading source. According to Harvard researchers Frank Hu and colleagues, the components most associated with increased intake are potato chips (1.69 lbs), potatoes (1.28 lbs), SSBs, (1 lb) unprocessed red meats (0.95 lb) and processed meats (0.93 lb), in that order. http://www.ncbi.nlm.nih.gov/pubmed/21696306.
  1. African-Americans need many changes to diet to affect CVD risk factors, including additional whole grains, vegetables and fish intake, reduction in saturated fat, sodium as well as sugar according to study by Carson et al in September 2012 Journal of the Academy of Nutrition and Dietetics. PubMed: Cardiovascular Health of Urban African Americans (I think this applies to all of us.)
  1. The most influential factor driving childhood obesity is parental weight, especially that of the mother, independent of the effect of socio-economic status. See Causes of Obesity also, http://www.ncbi.nlm.nih.gov/pubmed/19165162 A new study from Elmear Keane and  colleagues in Ireland provides further support for this. PubMed: Measured weight status and familial SES

To look at the combination of genetic pre-disposition to obesity and in the intake of SSBs, Qibin Qi  and colleagues at Harvard School of Public Health looked  at 32 genetic loci (called “risk alleles”) known to be associated with BMI.  They grouped the 32 loci into 3 groups and looked at prospective 4 year beverage intake data from two large studies. Participants who were obese at baseline were excluded.  They found a rising BMI from greater intake of SSBs. For every 10 risk alleles, the increases for BMI was 1.0 for one serving a month, 1.2 for one to four servings per week, and 1.85 for one or more servings per day. In a sub-analysis,  they excluded the FTO gene, known for its impact on body weight, and found similar results. They concluded that “persons with a greater genetic predisposition to obesity appeared to be more susceptible to the deleterious effects of sugar –sweetened beverages on BMI. PubMed: Sugar-Sweetened beverages and Genetic Risk of Obesity The implication of this article is that NYC may have overreached…applying a rule to all when only some are most affected.

Two intervention studies were published in the New England Journal of Medicine, along with the study above.  One, by Cara Ebbeling and colleagues, divided 224 overweight and obese adolescents into 2 groups. The first group received home delivery of non-caloric beverages and were followed for another year. The second group acted as controls. Consumption of SSBs in the first group declined significantly but at the end of 2 years there was not difference in BMI between the two groups.PubMed: Randomized Trial of SSB and Adolescent Weight

The other intervention study, by de Ruyter and colleagues, had a larger sample size (641 normal weight children from 4 yrs 10 months to 11 yrs 11 months) and was a double blind model.  Half received a sugar-free non-carbonated beverage and the other have a sugared non-carbonated drink.  26% dropped out of the study. If this were an obesity drug study, a great deal would be made of this. Evidently they dropped out because they no longer liked the taste of the beverage. The researchers assume they went back to consuming sugared beverages. They found that “masked” replacement of the SSB by a sugar-free beverage significantly reduced weight gain and fat accumulation in normal weight children. The difference was 1.01kg. However, the authors calculate that approximately 0.8kg of the differences in weight gain was due to fat mas and associated muscle and other tissues.  PubMed: Trial of sugar-free or sugar-sweetened beverages

You can listen to David Allison discuss the SSB issue and these studies at http://themixuab.blogspot.com/2012/09/do-sugar-sweetened-drinks-drive-obesity.html.

These studies were published in the New England Journal of Medicine September 21, 2012 edition.  Mayor Bloomberg could have looked at other recently published studies to see the difficulty of regulating consumption of SSBs.

Levy et al looked at school nutrition policies and price interventions directed at youth consumption of sugar sweetened beverages (SSBs). They found that school nutrition and price policies reduce SSB consumption and that reduced SSB consumption is associated with a reduction in energy intake that “can” influence Body Mass Index Their review of the literature found that the effects of nutrition policies on BMI were less conclusive, possibly due to the lack of adequate follow-up period or that reduced SSB consumption in school is compensated for by increased SSB consumption outside of schools. The authors’ concluded that, “The reduction in energy intake from even just one 8-oz serving of SSB appears enough to have important effects on the prevalence of overweight and obese youth if policies are started at early ages and maintained.”  PubMed: Review of the literature on policies youth consumption of SSB

Of course, the key word here is “if.” Some of the calculations of the benefits of reducing or eliminating SSBs, are premised on the assumption that the calories contained in SSB will not be compensated for by other caloric intake. PubMed: Effect of school district policy change on consumption of sugar An analysis of SSB consumption in middle schools compared students in states which reduced access and purchase with those that did not. The main finding was that SSB consumption was not associated with state policy, i.e. in-school access is reduced but overall consumption is not changed. PubMed: Banning all sugar-sweetened beverages in middle schools A study by Wang et al, calculated what a penny-per-ounce tax on SSBs would mean for health care costs and diabetes. They calculated that 40% of the calories in SSB would be replaced by other caloric intake and 60% of SSB calories would not be replaced. This would translate to a mean reduction of 0.9 pound in mean at the population level, with a greater impact on younger adults, a 1.5% reduction in the number of adults with obesity. This decline would further translate into a reduction of new cases of diabetes by 2.6% and cost savings over ten years of $17.1 billion. PubMed: Penny-per-ounce tax on sugar-sweetened beverages. However, the 40%-60% split was only an estimate, it wasn’t based on experimental or real world results.

News reports indicate 24 states and 5 localities which proposed taxes on sugar sweetened beverages failed in their attempts over the past 2 years. Industry resistance to taxes and regulation has been strong and effective. ( Reuters: Special Report: How Washington went soft on childhood obesity http://www.reuters.com/article/2012/04/27/us-usa-foodlobby-idUSBRE83Q0ED20120427, accessed April 28, 2012)

Worldwide, some 20 countries have banned all sugar-sweetened beverages from schools and about 12 have banned 100% fruit juice as well, according to Barry Popkin and colleagues. PubMed: Global Nutrition Transiiton and the Pandemic of  Obesity Hawkes and colleagues have found that 26 countries have made explicit statements on food marketing to children and 20 or so are developing explicit policies in the form of statutory guidelines or approved forms of self-regulation. PubMed: Regulationg the commercial promotion of food to children

Denmark last year became the first nation to tax sugar but has since rescinded its tax because it was hurting domestic businesses while Romania has introduced a lower value-added-tax on staple foods. New Zealand is researching taxing foods with little or no nutritional value at higher rates than more nutritious foods. Professor Sir Nicholas Wald, director of the Wolfson Institute of Preventive Medicine has proposed an all-embracing SASS (salt, sugar, alcohol and saturated fat) tax.  PubMed: Is a tax on junk food moving closer?

One alternative approach is to tax all SSB sales, whether in school or out of school. Researchers have pointed out that, in 2007, 34 states taxed soda sold in grocery stores and 39 taxed soda sold in vending machines at mean rates of 3.4% and 4.0% respectively. The tax was never greater than 10% of the price.  Several studies are cited which showed no effect on BMI from such taxes. PubMed: A review of the literature directed at the youth consumption of SSB Sturm et al point out the greater benefit of larger tax than a smaller tax to affect behavior. PubMed: Soda taxes, soft drink consumption, and children’s body mass index.

For an excellent discussion of food taxes, see these presentations from University College, Dublin.

The New York City experiment will be tested in court and then it will be tested in practice to see if it actually has an effect on reducing weight gain or causing weight loss. But there are other public policy options worth exploring. Mayor Bloomberg also proposed a waiver for the city from the Department of Agriculture to allow restrictions on the purchase of certain foods by families with SNAP benefits. SNAP is the Supplemental Nutrition Program for Women, Infants and Children. SNAP is a federal program designed to reduce hunger and food insecurity among low-income Americans.  In a study using store scanner data, Tatiana Andreyeva and colleagues at the Rudd Center for Food Policy and Obesity  looked at patterns in the New England states. They found on average that SNAP households purchased 689 oz of beverages per month, including 399 oz or 58% of SSBs. The researchers estimated that SNAP spends annually between $1.713 billion to $2.05 billion on SSBs. They note that no-calorie beverages and water were equally available and no more expensive. SNAP households appear to obtain more total energy from SSBs than the general, higher-income population. PubMed: Grocery Store Beverage Choices by Participants in Federal food

So there are other public policy options. But this debate over SSBs show the problem with over-simplifying obesity to one source, fashioning a simplistic response, only to see the “solutions” fail. This stuff is difficult and we need to appreciate how difficult it truly is.

 

How to communicate with a child about their weight

September 27th, 2012

For parents, there are a number of tense situations involving raising a sensitive issue with your children. Their weight is one of the most sensitive. So the STOP Obesity Alliance and the Alliance for a Healthier Generation have issued a conversation guide for parents and caregivers on how to approach issues, such as, understanding the BMI, cultural differences, body image, bullying, weight bias, inter-family weight differences, and, parental obesity. To access the materials, go to http://www.stopobesityalliance.org/research-and-policy/alliance-initiatives/families/

It’s not about Western Lifestyle!

September 26th, 2012

Herman Ponzer of the Department of Anthropology at Hunter College and colleagues have challenged one of the major assumptions in current thinking about obesity. The assumption is that Western lifestyle differs markedly from those of our hunter-gatherer ancestors and that these changes are responsible for our current obesity epidemic. To look at this Ponzer and colleagues studied daily energy expenditure of the Hadza foragers. The Hadza live in a savannah-woodland environment in Northern Tanzania. It is believed that the lifestyle of the Hadza are similar in critical ways to our Pleistocene ancestors. Hadza women gather plant foods; while the men engage in hunting. 95% of their calories come from wild foods including tubers, berries, game, baobab fruit and honey. The researchers expected that the Hazda would have lower body fat than Western populations and that, with their natural diet and lack of mechanization, they should expend more energy than individuals living in market economies with comparatively sedentary lifestyles and more energy dense diets.

Surprise! The authors state, “Contrary to expectations, measures of TEE (total energy expenditure) among Hadza adults was similar to those in the Western (U.S. and Europe) populations.” Because the Hadza are smaller than Westerners, their energy spent on their basal metabolic rate (BMR) was smaller than for Westerners. According to the researchers, “ Measurements of TEE among Hadza hunter-gatherers challenge the view that Western lifestyles result in abnormally low energy expenditure, and that decreased energy expenditure is a primary cause of obesity in developed countries. Despite higher PAL (physical activity level) and dependence on wild foods, Hazda TEE was similar to Westerners and others in market economies. Further, while Hadza differed from Western populations in body fat percentage, variation in adiposity both within and between populations was not correlated with PAL nor with TEE. The lack of correspondence between TEE, PAL, and adiposity in our Hazda and comparative samples is consistent with previous DLW (doubly labeled water) studies in Western populations. The similarity in TEE among Hadza hunter-gatherers and Westerners suggests that even dramatic differences in lifestyle may have a negligible effect on TEE, and is consistent with the view that differences in obesity prevalence between populations result primarily from differences in energy intake rather than energy expenditure…Data on hunter-gatherer TEE provide additional perspectives on Paleolithic humans and on the origins of farming. While the lifestyle of late Pleistocene hunter-gatherers was no doubt highly active as seen in foragers today, our results suggest that their daily energy requirements were likely no different than current  Western populations…TEE is remarkably similar across a broad, global sample of populations that span a range of economies, climates and lifestyles. Not only is TEE statistically indistinguishable between Western, foraging, and farming population levels. We hypothesize that TEE may be a relatively stable, constrained physiological trait for the human species, more a product of our common genetic inheritance than our diverse lifestyles.”. They cite another study pointing to the body’s complex physiological responses to dieting and weight loss support this view PubMed_Hunter Gatherer Energetics and Human Obesity

This is not the first study making this observation. Ramon A. Surazo-Arizu of Loyola University Medical School and colleagues studied the rise of obesity in three countries: Jamaica, Nigeria and the United States. They found that women in Nigeria and the US had higher weight gains than men but the reverse was true for Jamaicans. They write, “The steep trajectory of weight gain in Jamaica, relative to Nigeria and the US, is most likely attributable to the accelerating effects of the cultural and behavioral shifts which have come to bear on transitional societies.” The three countries span economic development from highly developed (U.S.) to middle-income (but stagnant in Jamaica’s case) to low-income (Nigeria). The average weight gain was .43 kg/year in Nigeria, 1.28 kg/year in Jamaica and .38 kg/year in the US. The researchers observed, “The prevalence of obesity was lowest in Nigeria, although during this time period participants in that rural community were gaining about as much weight as those followed in the U.S…Over the last 10-15 years societies as geographically and culturally distant as Barbados, Russia, Kuwait, and Japan have all experienced rapid increases in relative weight, affecting both children and adults. In the US the shift in the BMI trend slope occurred in the mid-1980’s and a 5-fold increase in the rate of change/year has been observed subsequently. Even Norway – with its historically low obesity rates and high participation in leisure time physical activity – experienced an abrupt up-turn around 1990. Clearly some “common source exposure” is shifting the population distribution of weight right-ward and virtually all segments of the societies that participated in the world economy are being affected. While it is assumed that lifestyle changes related to the growing consumer economy are the driving force it has been difficult to define and quantify the specific factors…Although Jamaica has undergone rapid cultural changes over the last 20 years, accompanied by a decrease in the rural population, it has experienced stagnating or negative economic growth. While accurate economic data are difficult to obtain, it is also unlikely that average Nigerians have seen any substantial increase in their material standard of living over the last 2 decades. Thus, the lifestyle changes required to fuel weight gain do not require general economic development, and instead may reflect the penetration of market-based consumption patterns into stagnating or declining economies. These observations suggest that it is the character of social development, not necessarily the level of economic activity per se that is driving the combined obesity-diabetes epidemic in many poor and middle-income countries.” PubMed: Rapid increases in obesity in Jamaica, compared to Nigeria, US

More bad news for the BMI

September 26th, 2012

Nirav Shah of NYU School of Medicine and Eric Braverman of Weill-Cornell Medical College have published more evidence on the limitations of the Body Mass Index (BMI). Their study looked at adults according to BMI, DXA, fasting leptin and insulin. 39% of the subjects were found to be obese by DXA (which is a direct measurement of body fat) but not by BMI. BMI misclassified 25% of the men and 48% of the women. A strong relationship was found between increased leptin levels and increased body fat. Women demonstrated a clear correlation between advancing age and increasing miscalculation, with over half misclassified by age 60-69. This association was not apparent for men.

The authors state, “BMI significantly underestimates adiposity. A better cutpoint for obesity with BMI is 24 for females and 28 for males. ..Obesity, body fat and increased adiposity are more prevalent than the American public and American physicians are aware of. This is contributing greatly to multiple co-morbidities such as hyperlipidemia, coronary artery disease, hypertension, and diabetes. The current systematic underestimation of adiposity in large scale studies, and subsequent use of such studies for public health policy-making, can readily be corrected, resulting in a more appropriate sense of urgency and more cogent weighing of public health priorities.” PubMed: Measuring Adiposity in Patients

 

Denmark pulls back on fat taxes

September 19th, 2012

Denmark has decided to repeal its tax on saturated fats and forego other taxes on sugar-sweetened beverages and foods after finding that Danes simply went to Germany to buy the foods at lower prices. See FoodNavigator: Fat-tax-why-is-Denmark-such-a-quitter

If you want to see a really well-informed discussion of such taxes, see these presentations from Professor Mick Gibney, Dr. Anne Nugent, Dr. Kevin Denny and Professor David Madden at University College Dublin, Ireland. UCD: Seminar fat and sugar taxes

 

Obese Children consume fewer calories than normal weight peers

September 18th, 2012

In a new paper, researchers from the University of North Carolina Chapel Hill looked at children aged 1-17 dietary patterns. What they found surprised a lot of people. Turns out that overweigh and obese girls over 7 and boys over 10 actually consumed fewer daily calories than their healthy weight peers. They hypothesized that one explanation may be that increased energy intake in early childhood and is related to the onset of obesity while another mechanism such as energy expenditure may be more influential in maintaining overweight/obesity status through adolescence. In other words, the normal weight adolescents may get more physical activity and would be expected to eat more to compensate for the effects of greater energy expenditure. This is consistent with the recent study regarding the role of the resting metabolic rate on hunger and food intake. See this study at PubMed: Skinner AC, Self_reported energy intake by age in Overweight