Posts Tagged ‘Obesity’

Does a pound of apples equal a pound of potatoes?

Wednesday, May 22nd, 2013

In January, 2013 a rather startling article in JAMA concluded that its not only okay, but actually may healthier, to be somewhat overweight and it’s not bad to even be a little obese.

That conclusion took many of us by surprise and was hard to swallow. I read it and went into my hypercritical mode.

To start with almost everyone would agree that those who are really skinny may not be healthy, unless they’re a marathon runner or some other kind of well-trained athlete. And, by the same token, being truly obese is bad for you.

But why should people who are overweight be healthier than those of us who are reasonably trim? And, to step things up a notch, why should being mildly fat not carry some risk?

This was a meta-analysis which an online dictionary  defines as a systematic method that takes data from a number of independent studies and integrates them using statistical analysis.

In other words, the authors weren’t doing their own large prospective study (one that starts at the current time and follows a group of research subjects over a {hopefully} extended period of time) but was a project that (retrospectively) reviewed the past work of others.

The gold standard in medical research, from my reading, is to have a randomized, controlled, double-blinded, prospective study. That translates into the research subjects being allotted by a method that picks them in a non-biased fashion to some kind of treatment or another (or none) and neither the researchers or the “researchees” know what group they’re in. Ideally the total number of subjects should be quite large and the study starts when they’re chosen and goes on from there.

Here there wasn’t a treatment and it was reasonable to look at other authors’ work done in the past, but of course there are hazards in doing so. What often appears to happen, is a group of researchers say, “Let’s look at problem X by seeing what other medical scientists have done. And we’ll accept or not accept those previous studies by criteria we can agree upon.”

These authors retrospectively examined data from 97 studies including nearly three million subjects (2.88M), but those came from a pool of over 7,000 articles and excluded, for pre-set and logical reasons, 98% of those.

In the same edition of JAMA were comments in a superb editorial piece, “Does Body Mass Index Adequately Convey a Patient’s Mortality Risk,” It mentioned a 1942 statistician working (as my Grandpa Sam did) for the Metropolitan Life Insurance Company said staying at the same weight you were at at age 25 meant you had a better chance for a longer life. Later on height and weight tables were compiled and a number called the body mass index could be derived using those two measurements and, in general, the CDC said, it was a reasonable estimate of how lean or chubby you were.

Normal BMI is said to be between 18.5 and 25 (I’m at 21 at present), so underweight would be represented by those with a BMI <18.5, the overweight range is 25-30, low-grade obesity from 30 to 35, grade 2 obesity from 35 to 40 and grade 3 obesity from 40 on up.

Since the origin of the concept behind BMI was European (by a Belgian polymath somewhere between 1830 and 1850), it’s usually measured as the weight of a person in kilograms divided by their height in meters squared. A close American version is weight in pounds divided by height in inches squared and then multiply by 703.

So at 150 pounds and 71 inches tall (I’ve lost at least a half an inch over the years), my BMI calculates as 20.9. If I weighed 200 pounds, my BMI would be 27.9 and I’d be called overweight. At the most I’ve ever weighed (216) and with my younger height of 71.5 inches, my BMI was 29.7. That’s a 66 pound difference; I thought I was fat at that weight.

Total mortality, the editorial said, has a U-shaped relationship with BMI, with considerably higher risk of death at BMI’s less than 18.5 or greater than 30.

That’s long been the traditional viewpoint, but the data in the January JAMA article didn’t seem to agree with the latter finding. The editorial clarified matters considerably, saying the normal range can be divided in two parts with those having a BMI between 18.5 and 22 having a higher mortality rate than those who BMI is between 22 and 25.

I’d go a step further by saying there are those of us who have a relatively low BMI because we’re lean and exercise a lot and others who have a similar BMI because of chronic illness or poor nutritional intake.

Lean and well-muscled

Lean with a muscular torso

I have well-muscled legs (I ride a recumbent bike for 15+ miles and 500+ calories six days a week), but I’ve never had strong arms and I’m small-boned. Since the beginning of 2009 when I went back on my own eating plan and really increased my exercise time, I’ve gone from a 38 inch waist to 33 and given away slacks and belts. If I weighed 200 pounds and was a large-boned guy with a great torso and a small waist, I think my risk factors for death would be less than if I had a big belly and weighed the same 200 pounds.

So we need to add waist measurement and probably blood pressure, blood lipids (HDL cholesterol and triglycerides) and fasting blood sugar to the BMI to get a better estimate of risk factors for dying.

That still doesn’t explain why those with a BMI of 30 to 35 appear to do well. One comment is that docs have gotten considerably more aggressive in looking at and managing blood pressure, lipids and elevated blood sugars in those of their patients who are overweight or obese.

Weighing what I do now, down nearly 30 pounds since early 2009, my own physician hasn’t suggested I get a fasting blood sugar or a lipid panel for several years.

I bet she would if I weighed 216 again.

 

 

 

Lessons unlearned

Thursday, April 18th, 2013

I weighed 153 pounds this morning, so I’m back on my diet plan until I’m under 150 again. Today I had fruit and cereal for two meals and a small amount of Thai leftovers plus a considerably larger amount of spinach for my big meal. I also went to our  health club and rode a recumbent bike for long enough to burn 500 calories and “cover” 15+ miles. I shoveled snow, wet heavy snow at that, for our house and our elderly neighbors place three times (we’ve had over 20 inches of snowfall in the past three days).  And of course, as I’ve mentioned before, I quit smoking in 1964.

This is not what we eat.

This is not our typical meal.

After diner I looked at recipes from Martha Rose Shulman’s book, The very best of Recipes for Health. Shulman writes a healthy food column in the New York Times online version. I’ve looked at it frequently and we recently purchased her book. Lynnette made a Quinoa and Tomato Gratin yesterday and we immediately added it to our “Keeper List.” A lot of the recipes are vegetarian (about 1/3 of our main meals fit in that category), but she’s got some turkey and fish dishes.

What sparked this column was a Pure Study report in JAMA dated April 17, 2013. The title is lengthy: “The Prevalence of a Healthy lifestyle among Individuals with Cardiovascular Disease in High-, Middle-, and Low-Income Countries” In 2009 an article in the American Heart Journal described the PURE Study, the Prospective Urban Rural Epidemiology Study. The World Health Organization defines epidemiology  as the analysis of the distribution and determinants of health-related states or events (including disease), and the application of this knowledge to the control of diseases and other health problems.

The PURE Study began with a premise we’re all (hopefully) familiar with; over the past 50-60 years we’ve seen an epidemic of obesity, diabetes and cardiovascular disease in much of the world, especially in countries, like the United States, where many smoke, eat too much of the wrong foods and exercise too little

Let’s start with smoking in this country. The CDC published data online from a 2010 study that said over 19% of adult Americans smoked cigarettes. Over a fifth of those aged 18 to 64 were in this group, but only 9.5% of those over 65. Hispanics (12.5%) and Asian-Americans (9.2%) did better than whites or blacks, but over 30% of American Indians and Alaska Natives were smokers.

Smoking percentages went sharply down with more education: 45.2% of those with a GED smoked, 23.8% of those with a high school diploma, under 10% of people who had graduated from college and 6.3% of those with a postgraduate degree.

Similarly those living below the poverty level were more likely to be smoker (28.9%) than those with incomes at or above that level (18.3%).

There’s lots of data linking obesity, low-quality diets, and lack of exercise with cardiovascular disease including heart attacks and stroke. How one defines a low-quality diets varies around the world; living here, I thinks it’s lots of fast food and little emphasis on fruits and vegetables.

As a young physician I saw many patients who didn’t seem to get the message that their unhealthy lifestyle may well have contributed to their cardiovascular disease. When I was 53 my four-year-older brother died of a heart attack. Almost all of the rest of the family lived to 90 or longer, but he had smoked two to three packs of cigarette a day, gained fifty or so pounds and seldom exercised. If I had a heart attack or a stroke and survived, I’d look closely at my risk factors and try to do something about them.

The PURE study following over 150,000 adults (ages 35 to 70) in over 600 urban and rural settings in 17 different countries. This article discussed 7519 participants who had already had either a stroke or coronary artery disease and determined if they had stopped smoking, altered their eating habits and/or gotten more exercise.

The results were striking, but not at all amazing to me. Guess what proportion improved in all three arenas.

4.3%

Over fourteen percent of these post-cardiovascular-event adults didn’t take up any of the three logical behavior changes.

That made no sense to me. Could it be genetic pre-programming? Let’s look at data on one of the three behaviors.

A rodent exercise machine

A rodent exercise machine

The New York Times had a recent online article titled, “Why we’re motivated to Exercise or Not.” Scientists at the University of Missouri took ordinary lab rats and put running wheels in their cages; They bred the males and females who were the most active to each other and did the same to those who ran the least. They continued this over ten generations and ended up with two disparate groups: one ran ten times as much as the other.

They examined the physiques of the rodents to see if one group was fat or had poor muscle tone: no significant differences were found. Then they examined genes in the reward portion of the rats’ brains; the part that gives motivation to do things because they cause enjoyment. Lots of differences were noted here.

Does that mean those of us who exercise do so because we’re genetically predisposed to do so and the rest are doomed to be sluggards?

The lead investigator, Dr. Frank Booth, thinks it’s quite probable that humans have a genetic motivation to exercise or not. But he’s quoted as saying his results “are not meant to be an excuse not to exercise.”

And that’s without having the added incentive of having had a heart attack or a stroke.

What does it take to change our habits of a lifetime?

 

 

 

 

 

 

 

Adulthood: when your BMI is more important than your IBM (stock)

Thursday, February 9th, 2012

I do this at home, without clothes

In my last post I wrote about our upcoming generations and their obesity issues. Unfortunately, as you might have easily been able to predict, that carries over into adulthood. The same issue  (Feb 1, 2012)  of the Journal of the American Medical Association (usually called JAMA) had several articles on adults also. To begin with the National Health and Nutrition Survey (NHANES) looked at the body mass index (BMI) of men and women from 1999 through 2010.

“AARRGGHH” you say, “Why the hell should I care about whatever BMI is enough to try to understand it?”

Well, that’s a tough question, I admit. But BMI is the standard way of deciding if a person is too thin, normal, overweight or obese. So let’s give it a try.

Your BMI is a number calculated using your height and weight.  If you weight 250 pounds and you’re a seven-foot tall basketball professional center player, you’re unlikely to be obese. But if you’re five foot, six inches tall, and don’t exercise at all, like the adolescent I was reading about recently, you’re far too heavy. In the first case, the athlete has a lot of muscle, whereas the youngster is almost certain to be carrying around a lot of excess fat.

For a long time physicians just weighed their patients. That plus eyeballing their bodies in an exam room works for most people. Then along came the BMI as one way of getting a little more scientific. I looked online for the history of the use of body mass index as I suspected it was “invented” by a European (it was). It certainly seems to me to favor the metric system. There it’s easy to figure out your BMI; you divide your weight in kilos by your height in meters. It’s much more complicated using pounds and inches (BMI = weight in pounds divided by height in inches squared and that number is multiplied by 703) The CDC explanation of BMI is helpful and also supplies a “widget” you can download and a calculator if you just want to bookmark the website.

height counts, for adults too

So now you’ve (hopefully) figured out your own BMI; What does it mean and how reliable is it?

First the numbers: most people with a BMI under 18.5 are skinny, underweight. That probably excludes a whole passle of long-distance runners. Most people with a BMI over 18.5 and under 25 are in the “normal” weight category. I used the CDC calculator and my number is 20.5. Most whose magic number is 25+ and less than 30 are overweight and almost anyone whose BMI is over 30 is obese. The teenager I mentioned above has a BMI of 40.

Okay, you say. Now what do I need to do once I know what category I’m in.

I’d start with the eyeball test. Do you have a roll around the middle? In early 2009, weighing only three pounds more than I had for twenty years, I clearly did. I made up my mind to do something about that excess flab, knowing that fat in the belly also implies arteries that are narrowing down.

After losing thirty pounds and keeping it off, I bounced up after the Superbowl and went back on my diet, i.e., consuming fewer calories. I went to a meeting last evening; there were lots of goodies, but I ate only carrots and cucumbers. This morning I’m at 148.2 pounds, smack dab in the middle of the three-pound “ideal weight” range I decided on.

Harvard Medical School just published a piece titled “Choosing the diet that will work for you.” The central theme is cutting calories.

Reading Taubes: part one

Saturday, July 2nd, 2011

Avoid white bread

A while back one of my blog readers asked if I had ever read Taubes. I wasn’t sure if that was a book title, a diet plan or an author, so I Googled the word and eventually purchased two books written by a veteran science writer, Gary Taubes.

Taubes studied applied physics at Harvard and areospace engineering at Stanford, then wrote articles for Discover and Science plus four books. He looks for scientific controversises and wades into them. In July 2002 he published an article in the New York Times Magazine titled “What if it’s All Been a Big Fat Lie,”

The article takes us back to the Adkins diet craze. Dr. Atkins, trained in cardiology, was significantly overweight and used a JAMA study as a basis for his own personal diet plan. He then published two books urging dieters to severely limit carbohydrate consumption. At one point it was estimated that one out of eleven North American adults were on his diet. His company made over $100 million, but filed for Chapter 11 bankruptcy in 2005, two years after he died.

Taubes explores some of the same turf, saying it’s refined carbohydrates that make us fat. His initial plunge into the field was the NYT piece, followed by a 2007 book, Good Calories, Bad Calories and now a 2011 book, Why We get Fat: and What to do About It.

Taubes has hefty credentials as a science writer; he is the only print journalist to have received the Science in Society Journalism Award three times. Currently he’s a Robert Woods Johnson Foundation investigator in Health Policy Research at UC Berkeley’s School of Public Health. But his initial article ignited a firestorm. In the piece Taubes mentions that the common veiwpoint links the kickoff of the obesity epidemic  (in the early 1980s), to cheap fatty foods, large portion servings (at commercial establishments presumably), an increase in food advertisements and a sedentary lifestyle.

He would beg to differ, invoking what he terms “Endocrinology 101,” an explanation that says human evolution was not designed for a high-sugar, high-starch diet. Until a comparatively recent era (roughly 10,000 years ago) we were not agriculturists, but hunter-gatherers. So Taubes thinks the problem is our increased consumption of sugar, high fructose corn syrup, white bread, pasta &  white rice.

Others think he picks and chooses his facts. I don’t think he’s wrong in his basic premise, but he also disagrees with the ideas of “calories in; calories out,” avoiding saturated fats and exercising being important in weight control (He seems to think people who exercise then hurry off to eat more).

more than one way to "thin a cat"

I’m down thirty pounds since early in 2009, have easily kept the weight off by exercising six days a week, avoiding sugar & HFCS foods and eating lots  more veggies and fruits while cutting back on portion size of meat dishes.

I’ll read more on Taubes and his detractors and let you know what I agree with and what I don’t.