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