Posts Tagged ‘Biological factors affecting health and weight’

Rethinking Thin

June 12, 2008

Gina Kolata, author of the book Rethinking Thin, has a point of view: it is almost impossible to lose significant amounts of weight and keep it off. I respect her work, but take issue with her pessimistic tone. Here is a review of her book I placed on Amazon.com:

Most books on diet and weight control, and there are hundreds, fall into one of two categories: research-based but narrowly focused and selective in order to promote a specific point of view; or completely opinion-based and hyping some fad or promoting a product (which may be the book itself). Rethinking Thin falls into the first category.

Author Gina Kolata, a New York Times science reporter, contends that being “overweight” has been oversold as a health problem. She correctly criticizes the hugely profitable “diet industry” for capitalizing on people’s belief that they can and should try to change what they weigh. Her major argument is that people have little control over their weight and that, like height, it is mostly biologically determined through a poorly understood interaction of heredity and environment.

I agree with Kolata that being overweight is not necessarily a medical problem and also agree with her criticism of dieting, but I disagree with her emphasis on how little effect our behavioral choices have on the outcome. For example, she writes, “It must be that free will, when it comes to eating, is an illusion.” She throws out the baby “willpower” with the bathwater of self-blame and shame. The problem, as I see it, is not with willpower but with the misuse of it in trying to comply with worthless diet plans and attempting to achieve unrealistic goals.

For some people there is a major genetic and/or biochemical component to their difficulty in maintaining the weight they desire. Ongoing research concerning the roles of leptin, ghrelin, insulin, and many other hormones in regulating body weight and hunger demonstrates that some obese individuals (perhaps as many as 5% or more) may have genetic mutations affecting their ability to control their appetite. Related lines of research indicate there are biological forces that make it difficult for most people to lose weight once it has been gained. Such evidence suggests that once fat tissue accumulates, a system of overlapping neurological and hormonal mechanisms works to prevent it from diminishing. Even so, most of us do have a significant degree of control over our eating and activity level, and this means we have some control over what we weigh.

Here are some relevant lines of research that Kolata essentially ignores:

  • The important role of “non-exercise activity thermogenesis” (NEAT) in determining what we weigh;
  • The thousands of success stories of people who have lost significant weight (and kept it off) through conscious control of eating and activity (this may be a small percentage of the overweight population, but a significant group);
  • The proven role of social networks and support systems in affecting our weight and lifestyle choices;
  • Exciting research (using sophisticated neuro-imaging) which shows how and where the “conscious” brain exerts influence on our eating and impulse control (including the role of “won’t power”);
  • Extensive research on consumer behavior when it comes to food choice, portion control, and automatic or impulsive eating behavior;
  • Research on stages of self-change and willpower fatigue (and ways to increase self-control and overcome learned helplessness).

Kolata concludes her book with this statement, which is a bit pessimistic in tone, but also offers realistic hope for people who are interested in taking action toward improving their health: “The lesson is, once again, that no matter what the diet and no matter how hard they try, most people will not be able to lose a lot of weight and keep it off. They can lose a lot of weight and keep it off briefly, they can lose some weight and keep it off for a longer time, they can learn to control their eating, and they can learn the joy of regular exercise. Those who do best tend to be those who learn to gauge portions and calories and to keep their houses as free as possible of food they cannot resist. The effort, the lifelong effort, can be rewarding – people say they feel much better for it. But true thinness is likely to elude them.”

Please let me know what you think; are you an optimist or pessimist where weight management is concerned?

Body shape is as important as weight

May 31, 2008

Are you an Apple, or a Pear?

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Several recent studies and articles have highlighted how important WHERE we store fat is to our health. Excess weight is generally stored either in the abdominal area or in the hips, thighs, and buttocks, giving rise to the descriptive terms “Apple” and “Pear.” If you are an Apple (and these shapes appear to be partly determined by genes), you tend to have more visceral fat (fat around the abdominal organs) and this can lead to various diseases (type 2 diabetes, some types of cancer, heart problems, urinary problems, dementia, hypertension, and stroke). The only benefit to the Apple shape is lower risk of osteoporosis. Overweight men and post-menopausal women tend to be Apples. Also, smoking is associated with abdominal fat accumulation.

Pears are not as much at risk for the serious diseases listed above, but are more likely to suffer from osteoporosis, varicose veins, and cellulite. While a Pear can become an Apple, Apples do not morph into Pears.

The good news? Here is a quote from an excellent article on this topic in the U. C. Berkeley Wellness Letter (June, 2008):

While abdominal fat tends to accumulate faster than other fat, it also tends to come off faster. [More good news:] losing just 2 inches from the waist reduces coronary risk by 11% in men and 15% in women, according to one recent study.

Further information from Weight Management for Your Life:

Some research indicates that elevated waist circumference (Men: equal to or greater than 40 inches; Women: equal to or greater than 35 inches) is a more specific risk factor for some diseases, such as prediabetes, than weight or BMI. An increasing waist-to-hip ratio may be a better indicator of coronary artery calcification than either waist circumference or BMI.  Therefore, weight distribution, as opposed to weight alone or BMI, must be taken into consideration; belly weight (abdominal obesity, “visceral fat,” or “central adiposity”) is of most concern. [see also here]