Good insulin, bad insulin: Its role in obesity?

Gary Taubes makes insulin out to be a bad guy. In his latest article in Newsweek Magazine commenting on HBO's Weight of the Nation documentary, he once again challenges energy balance (energy intake versus energy expended) as a paradigm for understanding obesity. The author of Good Calories, Bad Calories offers an alternative theory: refined sugars and grains trigger insulin, which leads to fat accumulation. He also doesn't think much of physical activity as playing a "meaningful role in keeping off the pounds."

Is Taubes right? Not according to Jim Hill, Ph.D., a professor of pediatrics and medicine at the University of Colorado School of Medicine, Denver. Hill is the cofounder of the National Weight Control Registry, a registry of individuals who've succeeded in maintaining weight loss over time. He is also the co-founder of America on the Move, a national weight-gain prevention initiative.

At a session at Experimental Biology, Hill said that the the "energy-in energy-out" framework continues to dominate as correct in current scientific literature on obesity. When asked whether or not the rise of obesity epidemic is related to diet or physical activity, Hill simply responds, "Yes." That is because studies have shown that either restriction of calories or greater physical activity can lead to weight loss.

Then, what's wrong with Taubes's insulin hypothesis? First, it's important to point out that insulin is also a good guy. As kinesiologist John Ivy, Ph.D., of the University of Texas at Austin, pointed out to me a few years ago, insulin is too often misunderstood. The unfortunate consequence can be a detriment of muscle and strength. Ivy's own research is on muscle insulin resistance and how it is reduced with exercise.

BMI puts young Asian-American women at risk of being "skinny fat"

As if we needed any more reason to pick on Body Mass Index (BMI): new research finds that this most accepted approach for assessing overweight and obesity based on height and weight could lead to misclassification of young Asian-American women as healthy when they're really "skinny fat," which could put them at greater risk for type 2 diabetes and cardiovascular disease.

In my last post, I discussed the scary, growing problem of sarcopenic obesity (aka "skinny fat") in older adults, described as age-related muscle loss in combination with the accumulation of body fat. One common result of sarcopenic obesity is a misclassification using BMI as "normal-weight" in these aged individuals. Misclassification in older adults with sarcopenic obesity is just one reason why BMI is loathed by those interested in public health.

How to fight "job-esity"

Workplace programs are an effective and worthwhile way for employers to help improve the health of their employees and reduce medical costs, scientists said Tuesday at Experimental Biology 2012 in San Diego at a session organized by the American Society for Nutrition. 

The medical expenses for employees who are obese are estimated at about 42 percent higher than for those with a healthy weight, according to the Centers for Disease Control and Prevention. Yet for the approximately 60 percent of Americans who are employed, it may be the workplace itself that is at the root of weight gain in the first place.

Beyond calories in, calories out -- look to the Amish

What is wrong with "eat less, move more"? Most of us are familiar with this mantra as weight-loss advice. However, a new consensus statement from the American Society for Nutrition (ASN) and the International Life Sciences Institute (ILSI) contends that this energy-in-energy-out framework isn't really so simple.

The problem lies in that consuming fewer calories and burning more through physical activity doesn’t always translate well to weight management. That is not to say that the framework of energy balance—negative energy balance for weight loss; positive energy balance for weight—is wrong. At some level, it’s right; however, several factors come into the equation.

During a Saturday morning session of Experimental Biology (#EB2012) in San Diego, Calif., researchers discussed the topic of this complexity and promoting a new paradigm on energy balance.

Safe weight loss for seniors through diet and exercise

In the United States, the number of obese older adults has reached disturbing heights—now affecting approximately 20 percent of those ages 65 and older—and is only expected to rise as more Baby Boomers become senior citizens.

Weight loss through calories reduction or exercise are generally good for most people as an intervention in obesity, although the appropriateness of these methods has historically been a matter of controversy in older, obese adults.

A major concern with weight loss is the accompanying loss of lean tissue, which can accelerate existing sarcopenia (age-related loss of muscle and strength), and result in reduction of bone mineral density that could worsen frailty. This could lead to greater risk of bone fractures and broken hips. Studies have yet to provide sufficient evidence, one way or another, as to whether or not weight loss provides a true enhancement to quality of life.

Resveratrol influences belly fat behavior

Fat can not only be unsightly, but if it’s sitting on your belly, may also contribute to overproduction of signaling hormones called adipokines, which are linked to metabolic changes that can worsen health.

New research from Aarhus University has found that abdominal adipose tissue extracted from overweight adults, and then exposed to resveratrol, exhibited reduced adipokine production. According to these authors, "small interfering molecules such as resveratrol are, in this matter, hypothesized to possess beneficial effects and might improve the metabolic profile in human obesity."

The scientists obtained the abdominal adipose tissue via liposuction from seven women and one man, ages 43-55, who had body mass indexes categorized as overweight. All subjects were Caucasian, healthy and not on any medication that could confound the results.

Because previous studies in rodents have shown that calorie restriction reduces production of adipokines by activating an enzyme called Sirtuin 1, the scientists had hypothesized that resveratrol may act similarly. Resveratrol is well-known as a potent Sirtuin 1 activator.

This most recent in vitro study, published in International Journal of Obesity, suggests that regular dietary intake of resveratrol may guard against the metabolic changes that occur when there is excess fat on the body – as it has with rodents and monkeys.

Resveratrol is a phytoalexin (a plant-produced antimicrobial substance) found in small amounts, most notably, in red wine, as well as in other common foods such as grapes, peanuts, and chocolate. The most concentrated natural source is the Japanese Knotweed (Polyganum cuspidatum).

Resveratrol gained scientific interest after it demonstrated effects similar to calorie restriction in slowing the rate of aging and increasing the lifespan in a number of species including nematode worms, mice, and rhesus monkeys. In addition, resveratrol protects overfed mice from weight gain and lemurs from seasonal weight gain.

Source: Olholm J, Paulsen SK, Cullberg KB, Richelsen B, Pedersen SB. Int J Obes (Lond) 2010;34:1546-53.