Obesity and overweight are a huge public health crisis in the United States. Every week there are stories in the newspaper about how excess weight influences the risk of some disease. There are also many studies underway to find out which diet and exercise methods are best at helping people lose weight and keep it off, and to find drugs that can do the same. What follows are some recent developments in weight management research followed by links to websites with news stories about obesity and weight loss.

Disease risk

While there are many serious diseases that occur more often in people who are overweight or obese, another one may have recently been added to the list. Researchers recently reported the results of a study that followed more than 6,000 people for 35 years and concluded that people who had more abdominal fat (larger waist circumference) when they were in their 40s were three times as likely to develop dementia by the time they reached their 70s. Dementia is a condition in which people experience memory loss and personality changes due to abnormal structural changes in the brain that can occur with aging. The risk was slightly greater if a person was both obese and had a large belly; the risk was slightly less if they were just overweight and had a large belly.

It is unclear why having abdominal fat might increase the risk for dementia, but it is sobering to note that being overweight or obese in middle age not only increases your risk of physical problems but mental difficulties as well.

Weight loss methods

Researchers are always trying to find the most effective ways to lose weight. One recent study found that when people quit their exercise regimen, then restart again, it may be more difficult to shed the pounds that were gained in the interim. The conclusion of the study was that for an exercise regimen to be a beneficial weight control method, it really needs to be adhered to all year long, year-after-year, not seasonally or with some other irregular pattern. Of course, quitting exercise completely is the worst of all. The study should make people think twice before taking a break from their exercise regimens.

Another recent study demonstrated the benefits of exercise, even small amounts, for postmenopausal women. The large study concluded that just 10 - 30 minutes of exercise a day can improve the quality of life for overweight or obese women as measured by their physical and mental health. The Dose Response to Exercise in postmenopausal Women (DREW) study looked at various amounts of weekly exercise in postmenopausal women who were overweight and obese and determined that while more exercise was best, even lower levels of exercise improved the way the women felt both physically and mentally. Interestingly, improvement was not dependent on whether the women actually lost weight during the six months of the study, although several of them did. It appears that for women in middle age and beyond, increasing physical activity level just a little bit may improve overall health and well being.

Genetics of obesity

Genetic makeup is an important factor in obesity, but not in the way you might think.

The number of people with a simple genetic mutation that causes them to gain weight no matter what is probably very small. However, there is probably a genetic reason that people become obese, one that is shared by most people alive today. The environment in which our ancestors evolved was one of feast and famine. Those best suited to survive were the ones who craved high fat foods and were able to pack on the pounds during times of plenty in order to survive the lean times when food became scarce. This idea is sometimes called the “thrifty genes” hypothesis, referring to the fact that we are all likely descendents of those early humans who were genetically good at acquiring and storing fat. Of course, now these genes are not so helpful; with a fast food restaurant on every corner, the “famine” part is no longer relevant for most people. This mismatch between today’s Western environment and our greedy fat-hoarding genes makes us all predisposed to obesity to some extent. The two-thirds of American adults that are overweight or obese provide anecdotal evidence that this may be the case.

However, this should not absolve us of responsibility for our weight. Obviously some people are able to maintain a normal weight, even in this fast food culture. Blaming it on your genes won’t help the doctor save you when you are having a heart attack. It is still up to us to take the initiative in adopting a healthy weight.

The idea that we all share some predisposition toward obesity also does not rule out the role of other, less common genetic variants that may make obesity even more likely in some people. One aspect of obesity that appears to be genetically controlled is where people tend to store fat on their body - whether they are an apple or a pear shape. We know that an apple shape characterized by abdominal fat increases the risk of heart disease and type 2 diabetes more so than does fat carried lower on the body. Exactly what genes are involved, however, is still unknown.

Another factor that seems to be controlled by genes is how well an obese person will react to bariatric surgery such as gastric bypass. A recent study showed that two gene variants helped predict which patients would achieve long term weight loss after bariatric surgery: depending on which combinations of gene variants a patient had, they either tended to succeed or not to succeed in losing weight after the surgery. The gene variants are in genes of unknown function so further studies need to be done to determine how these genes might affect the ability to lose weight.

There have been a small number of genes identified that might actually increase the risk of obesity in people who have mutated forms of these genes. One is the melanocortin 4-receptor gene, which is involved in the control of feeding behavior. Mutations in this gene have been found to be strongly associated with obesity in several populations and may be responsible for a small proportion of obesity cases.

Another gene was identified more recently as contributing to obesity risk. The FTO gene increases the risk of obesity in people who have one mutated copy of the gene and the increase is even larger on those who have two mutated copies. This gene also increases the risk of type 2 diabetes. It is estimated that nearly 50% of people of Western and Central European descent have one mutated copy of the FTO gene. While the function of the FTO gene is still unknown there is a lot of research underway right now to figure it out.

Links to recent weight management news and developments

Dieting and weight control news on Science Daily, a digest of recent science research news.
http://www.sciencedaily.com/news/mind_brain/diet_and_weight_loss/

PubMed is a U.S. National Institutes of Health search engine that covers all research published in medical and bio-scientific journals.
http://www.ncbi.nlm.nih.gov/PubMed/

PubMed Central is the National Institutes of Health free digital archive of biomedical and life sciences journal literature.
http://www.pubmedcentral.nih.gov/

The U.S. Department of Agriculture’s Agricultural Research Service has recent news in food and nutrition.
http://www.ars.usda.gov/news/docs.htm?docid=1369

Medline Plus, a service of the NIH, has links to recent news stories about weight control.
http://www.nlm.nih.gov/medlineplus/weightcontrol.html#cat57

The U.S. Food and Drug Administration Center for Biologics Evaluation and Research is the government agency charged with reviewing and approving applications for new drugs and medical devices and their website has information about recent developments in these areas.
http://www.fda.gov/Cber/index.html

Information about clinical trials

If you are interested in finding out more about clinical trials for obesity or obesity-related diseases, the National Institutes of Health has a clinical trials website at http://clinicaltrials.gov/.

To find a clinical trial being conducted in your area, visit the Healia Clinical Trials Search page.