Food for Thought: WHAT are the CAUSES of OBESITY?
Obesity has been a problem in the United States for quite some time now. Most health care practitioners view obesity as a prelude to a variety of conditions that range from osteoarthritis to cardiovascular disease. An increasingly serious health issue involves obesity being associated with insulin resistance and type 2 diabetes. However, it’s not clear if obesity or diabetes develops first, and this question has been a focus of considerable debate and research in recent years.
A simplistic and sometimes convincing explanation of weight gain involves looking at calories consumed versus calories expended. The calorie in/calorie out concept readily explains weight gain when factors that seem to define the American lifestyle are considered. These factors include consuming large portions of high-fat and high-carbohydrate food coupled with a sedentary lifestyle. An estimated 68 percent of American adults qualify as overweight or obese because they eat more calories than they burn. Although this assessment of weight gain appears logical, there may be several other factors that contribute to the preponderance of obesity in the United States.
Research has shown that a lack of sufficient sleep (sleep debt) adversely affects the balance of at least two important hormone-like substances in the body. Prolonged periods of less than seven hours of sleep each night usually result in elevated levels of the appetite-stimulating ghrelin and reduced levels of the satiety-inducing leptin (1, 2). Exposure to excessive levels of BPA (bisphenol A is a known endocrine disruptor from certain types of plastics) has been shown to contribute directly to obesity in humans (3). Infections with adenovirus (there are 52 types of this DNA virus that can invade human cells) cause obesity in laboratory animals, and this may correlate with similar infections in humans (4).
In my opinion, the most fascinating new research on body weight variation shows that the intestinal flora (gut microbiota) can determine the efficiency of calorie extraction from the food that we eat (5). The microbes in the colon extract energy from the indigestible food passed on from the small intestine. These microbes ferment food that we cannot digest, and they keep most of the resulting energy for themselves. However, our gut microbiota do share some of the extracted energy with us, but the amount varies from almost nothing to nearly 10% of our daily calories. A good analogy here is to look at obese individuals like fuel-efficient cars. Their gut microbes are much better at extracting energy from food which, in turn, can contribute to weight gain. The intestinal flora from a lean person could be viewed as gas guzzlers because of reduced energy extraction efficiency from food material in the colon. Further research has shown that obese volunteers had more Firmicutes
species and fewer Bacteroidetes
species in their guts than did lean volunteers. When the obese volunteers lost weight, their gut microbiota populations shifted with an increase in the gas-guzzling microbes (Bacteroidetes
) and a decrease in the fuel-efficient microbes (Firmicutes
). A number of food companies and ingredient vendors are currently investigating the link between probiotic composition and weight control.
Keep in mind that diet and exercise are the cornerstones of any successful weight-loss program. I believe that dietary supplements for weight loss can offer meaningful help in weight loss efforts. Certain supplements for weight loss can provide benefit to the vast majority of consumers who seek to lose weight and strive for healthy living . To reach your weight-loss goals and to keep the weight off, it is imperative to change your diet, improve exercise habits and make sound lifestyle choices. And don’t forget determination. If you have the determination to stick with a supplement program together with diet, exercise and a healthy lifestyle, you will succeed.
Created by Dr. William J. Keller References
1. Sharma, S., Kavuru, M. Sleep and metabolism: an overview. International Journal of Endocrinology. 2010: 270832. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929498/
2. Body Weight and Sleep. Available at http://www.sleepdex.org/weight.htm
3. Hugo, ER, et al. Bisphenol A at Environmentally Relevant Doses Inhibits Adiponectin Release from Human Adipose Tissue Explants and Adipocytes. Environmental Health Perspectives. 2008; 116(12): 1642-1647. Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2599757/?tool=pubmed
4. Whigham, LD, et. al. Adipogenic potential of multiple human adenoviruses in vivo and in vitro in animals. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 2006; 290(1):R190-4. Available at: http://ajpregu.physiology.org/content/290/1/R190.long
5. Ley RE, et. al. Microbial ecology: human gut microbes associated with obesity. Nature. 2006; 444(7122): 1022-3. Abstract available at: http://www.nature.com/nature/journal/v444/n7122/full/4441022a.html