Field Notes

Experts Say Many Factors Contribute to Obesity

“When someone says of an obese person, ‘They should just eat less and exercise more,’ I say if it were that simple, obesity wouldn’t be the worldwide epidemic that it is,” says Claude Bouchard, PhD, a faculty fellow at the Texas A&M University Institute for Advanced Study (TIAS) and the director of the Human Genomics Lab at Pennington Biomedical Research Center in Baton Rouge, Louisiana. Bouchard studies the genetics of obesity and says there are dozens of factors involved in determining whether a person becomes overweight or obese.

“It’s a complex problem because there are so many drivers,” says Bouchard, who also is author or coauthor of several books and more than 1,000 scientific papers and a former president of the International Association for the Study of Obesity. “Approaches focus on only a few and forget that while we control them, there’s compensation taking place elsewhere. There are other drivers that come into play.”

He divides those drivers into four categories: social, environmental, behavioral, and biological. Social factors include less access to nutritious foods, more recreational eating, powerful and constant advertising, large food portions, poor school meals, eating on the run, food pricing, and fewer meals cooked at home.

Our physical environment affects eating habits as well, such as the absence of sidewalks, reliance on automobiles, building design, and environmental pollutants, according to Bouchard. Factors that can affect weight, many of which aren’t within a person’s control, include behavioral factors such as spending less time in strenuous activity, taking medications known to increase body weight, not breast-feeding, eating high fructose corn syrup, an increase in sedentary jobs, and high-fat diets and biological factors such as genetics, viruses, gut microbiota, adipose tissue biology, and metabolic rates.

“The biology is very complex,” Bouchard notes. “The response to environmental, social, and behavioral factors is conditional on the genotype of an individual. Your adaptation to a diet or a given amount of exercise is determined by your genes.”

He says more research is needed, but there’s a strong probability that diet and exercise programs for weight control or disease prevention will one day be tailored to an individual’s genetic makeup.

“Can we meet the challenge of identifying genomic predictors of the ability of a given person to respond favorably to a specific combination of food and exercise? I believe that we can,” he says.

— Source: Texas A&M University


Type 2 Diabetes Treatment May Cause Long Bouts of Hypoglycemia

Researchers at the University of Adelaide in Australia have discovered that a common treatment for people with type 2 diabetes could cause longer-than-normal periods of hypoglycemia, which may result in increased health risks to people with diabetes. The treatment involves using the peptide GLP-1 in combination with insulin.

A team of researchers at the University of Adelaide School of Medicine has investigated the impact of this combination therapy on how quickly the stomach empties after eating food. The results, published online in Diabetes Care, showed that the combination of GLP-1 and insulin slows down the rate of food being emptied from the stomach.

"Low blood sugar levels usually cause the stomach to empty rapidly. However, in the group studied on GLP-1 therapy, it emptied no more quickly than at normal blood glucose levels," says lead author and doctoral student Mark Plummer. "This is a concern because it means that a significant amount of food, and therefore glucose being consumed by a diabetic patient to prevent or treat hypoglycemia, is being retained in the stomach. This would have the effect of extending hypoglycemia and potentially putting the patient at risk."

Plummer says the sample group of 10 people was relatively small, "but statistically the results were significant.

"A diabetic patient really doesn't want their blood sugars to go too low because the brain requires glucose for normal functioning, and you run the risk of loss of consciousness, seizures, and even death in extreme cases," he says. "There were no life-threatening effects on the patients we studied, but their symptoms included sweating, palpitations, and visual disturbance."

Plummer says the study highlights the potential safety implications for the combination of GLP-1 with other therapies known to induce hypoglycemia. "Further research is needed in this area,” he says. “We believe there should be ongoing evaluation of this combination therapy for patients with type 2 diabetes to better understand the risks associated with it."

— Source: University of Adelaide