Energy Intake Responsible for Weight Increases in UK Women but not Men

October 9th, 2015 No comments »

Increased energy intake entirely accounts for increases in body weight in women but not in men in the United Kingdom, according to a 2011 paper from Scarborough and colleagues. Comparing data from 1986 and 2000, the researchers calculated that the predicted mean increase in body weight due to changes in total energy intake was 4.7kg for men and 6.4 kg for women. But the actual mean body weight increased 7.7kg for men and 5.4kg for women between the two time points. They concluded that increases in total mean energy intake are sufficient to explain the increase in mean body weight for women but not for men between 1986 and 2000. The men may have experienced a reduction in physical activity.

 

What Freshman 15?

September 3rd, 2015 No comments »

Obesity Panacea has done a great service in de-bunking the myth that college freshmen will gain an average of 15 pounds over the course of two semesters. Their blog points out that, to gain 15 pounds, students would need to consume an additional 1,750 calories each week, almost one full day’s worth ofc calories.

 

New Insights on the Intergenerational Transmission of Metabolic Disease

July 31st, 2015 No comments »

Dr. Arya Sharma has a very useful post on the transgenerational transmission of metabolic disease, including obesity. As Dr. Sharma points out, if anyone says that obesity is not genetic, they don’t know what they are talking about. The article cited by Dr. Sharma recalls an earlier post on a three-generation transmission of the memory of starvation. Just goes to show that there much to be learned.

 

Jules Hirsch, Obesity Research Pioneer, Passes Away

July 30th, 2015 No comments »

The New York Times reported this morning on the passing of Dr.  Jules Hirsch, a pioneer in obesity research. Twenty years ago, Dr.Hirsch and  colleagues produced a ground-breaking study showing  that,  weight is lost, metabolism slows down. This causes weight to plateau without even greater reductions in caloric intake. At some point, a patient becomes frustrated with the lack of progress and/or succumbs to the brain’s demand to assuage the sensation of hunger.

Dr. Hirsch provided a wonderful summary of brain and behavior vis a vis obesity in this 2003 publication in Cerebrum,  in 2003, from the Dana Foundation, Obesity: Matter  Over Mind.

Dr. Hirsch will  surely be missed by the generations of researchers and clinicians he trained, by colleagues throughout the world in obesity research ,as well as by family and friends.

For many years, Dr. Hirsch was a member of the Food and Drug  Administration’s advisory panel reviewing drugs for the treatment of obesity. As a witness to most of these hearings since 1998, I can say that fear spread across the faces of presenters from the pharmaceutical  company when Dr. Hirsch’s time came to ask questions. His approval  or disapproval had a wide impact on other panelists. Likewise, one could hear a virtual sigh of relief among pharmaceutical company presenters were there news Dr. Hirsch would be absent. His testament to scientific integrity will be surely missed.

 

Causes of Obesity: It isn’t Physical Activity

January 5th, 2015 No comments »

So, our popular culture, as well as many physicians, believe that increased physical activity can either prevent obesity or bring about weight loss. The Today Show is an example of this popular, if wrong, view.

Lost in all this panting-cries for more steps are the actual research results. So it was interesting to find this interview at the University of Delaware annual Foltyn Family Health Sciences Seminar with Dr. Amy Luke of Loyola University Chicago. Dr.Luke has a distinguished career and a host of peer-reviewed publications.

Dr. Luke has been at the epicenter of the debate over whether it is energy intake or energy expenditure (i.e. physical activity) that is the cause of the obesity epidemic. Her research has taken her to rural Ghana, the Seychelles, urban South Africa, Jamaica, and the U.S.  Using objectively measured criteria (stable isotope techniques and accelerometers in five cohorts) Luke found that in developing countries, residents were not expending significantly more energy than those in developed nations like the U.S.

She told the U.Delaware audience, “Physical activity is important for a whole host of health benefits, but it may not be as important as we thought in the prevention of obesity. This points to the need for strong objective measures of the factors on which we are basing public policy.” (Michelle Obama: are you listening?) Dr. Luke has concluded that it is diet, not physical activity, which is responsible for the obesity epidemic

 

ADA Urges Lower BMI Cutoff for Asian-Americans

January 5th, 2015 No comments »

The American Diabetes Association (ADA) is lowering the Body Mass Index (BMI) cutpoint for screening Asian-Americans for type 2 diabetes to a BMI of >23kg/m2. In the new article, the evidence for a lower BMI cutpoint is discussed.  The authors note the presence of Asian-Americans and the projections for their increasing population, especially in 10 states, including California, New York, Texas, New Jersey, Hawaii, Illinois, Washington, Florida, West Virginia, and Pennsylvania.  The authors also note the limitations of current measurement techniques, observing that  BMI does not into account the relative proportions of fat and lean tissue and cannot distinguish the location of fat distribution. There is a propensity for Asians to develop visceral versus peripheral adiposity which is more closely associated with insulin resistance and type 2 diabetes. The new standard is not a measure of increased mortality or morbidity but a guide how to use BMI to screen for the presence of type 2 diabetes, with a focus on reacting to BMI cut-offs for eligibility of weight-reduction services or treatment reimbursable by payers.

There a couple of points. First, it is unfortunate that the ADA is not taking on the use of BMI for criteria for products (such as anti-obesity drugs) or services. Changing the BMI cut-offs to accommodate a poor public policy only adds to the distortion of our understanding of excess adipose tissue. The paper understates the fact that the BMI is such a poor standard for use in clinical settings. Third, aside from the literature about cut-offs, the problem is “Who is an Asian-American?” In addition to covering a number of various ethnic groups, determining whether one is “Asian-American” has a host of problems, including the issue of inter-marriage. Demographers are having a hard time determining just what “Asian-American” means. The problem originates with the Census Bureau criteria, as well as the problem of inter-marriage and self-identification as Asian-American versus White. Historically, the Census Bureau has combined Asians, Native Hawaiians and other Pacific Islanders, even though there are significant differences in physiology and body composition between Asians and the other two groups. Listen to this interesting discussion on the Diane Rehm Show on NPR on January 5, 2015 on this very topic.

 

Weight Gains Among Normal Weight Adolescents Cause Adverse Metabolic Effects

January 5th, 2015 No comments »

Researchers in Finland have made an important finding that weight gain in normal weight adolescents carries adverse metabolic effects. The cardiometabolic effect was highly responsive to weight changes over time.

 

New Insight on the Effect of Time on Genetic Expression

January 5th, 2015 No comments »

A New Year’s Eve story in the New York Times reported on a new study about a well-studied gene, FTO, which is strongly correlated with the development of obesity.  Previous research had established that, on average, one copy of a variant of FTO tended to have an extra 3.5 pounds. Persons with two copies of the gene have an extra 7 pounds, significantly increasing the risk of becoming obese.

The new study, published in the Proceedings of the National Academy of Sciences, indicates that this effect did not exist before World War II. Using the longitudinal data from the Framingham Heart Study the researchers led by James Niels Rosenquist of Massachusetts General Hospital found a “robust” relationship between birth cohort and the genotype-phenotype correlation between the FTO risk allele and Body Mass Index (BMI) with an observed inflection point for those born after 1942. The authors observe that “genetic influences on complex traits like obesity can vary over time, presumably because of global environmental changes that modify allelic penetrance.”