Obesity

A recent study about a possible link between sugary drinks leading to obesity and then diabetes concludes,

our findings suggest that frequent consumption of sugar-sweetened beverages may be associated with larger weight gain and increased risk of type 2 diabetes, possibly by providing excessive calories and large amounts of rapidly absorbable sugars. Public health strategies to prevent obesity and type 2 diabetes should focus on reducing sugar-sweetened beverage consumption.

This sounds a little odd to me. How can they be sure it's just the sugar, and not the diet as a whole?

Ruth Kava from the American Council on Science and Health points out

Rather than attributing the increases in weight and diabetes occurrence to the increase in calories from drinking additional sugar-sweetened beverages, the authors seem to blame the sugar in the drinks. Women who increased their sugar-sweetened beverage consumption from less than one per week to more than one per day added over 350 calories to their average daily energy intake. No matter where those calories came from, they would lead to additional weight. An important comparison is lacking here: the authors should have compared the weight gain and cases of diabetes in women who had an equivalent increase in calories from eating foods.

In an accompanying editorial, Dr. C.M. Apovian noted that the women who had higher intakes of sugar-sweetened soft drinks also tended to have other lifestyle factors that could have contributed to their weight gain and increased disease risk. Such women tended to be less physically active, to smoke more, and to have higher total calorie intake and lower intake of protein and fiber. In other words, their overall lifestyle was less healthful than that of women who didn't increase their soft drink consumption.

Apovian's editorial is subscriber-only, even though the Journal of the American Medical Association claims its mission to be "To Promote the Science and Art of Medicine and the Betterment of Public Health". By keeping info out of the grubby hands of the public, I guess.

Iain Murray links to The Economics of Obesity, a fascinating article in The Public Interest by economists Inas Rashad and Michael Grossman on the causes of American obesity.

Obesity and sedentary lifestyles accounted for approximately 400,000 deaths in 2000 compared to 435,000 from cigarette smoking, 100,000 from alcohol abuse, and 20,000 from illegal drug use. Obesity costs more in annual medical care expenditures than cigarette smoking — around $75 billion in 2003 — because of the long and costly treatments for its complications. A large percentage of these costs are borne by Medicare, Medicaid, private health-insurance companies, and ultimately by the population at large rather than by the obese....

According to the economists Darius Lakdawalla and Tomas Philipson, declines in the real prices of grocery food items caused a surge in caloric intake that can account for as much as 40 percent of the increase in the body mass index of adults since 1980. Technological advances in agriculture caused grocery prices to fall, the authors show, and these declines caused consumers to demand more groceries. Government policy only heightened the effect by encouraging overproduction. Journalist Michael Pollan points to a shift in the early 1970s toward direct farming subsidies as another source of the rise in caloric intake. The old system, an agricultural-support arrangement designed to discourage overproduction of corn and other storable commodities, had much smaller effects on producers’ decisions. But the new system "free[d] them to dump their harvests on the market no matter what the price."

Important technological changes in the home kitchen seem to have fostered more caloric intake, too....Microwaveable meals and other foods that are easy to cook are desirable because they are quicker to prepare; they are also fattier and higher in caloric content...

Other factors that have contributed to the growth in obesity include the decline in physical activity and urban sprawl. Physical exercise has declined since 1980, and that decline is a proximate cause of the increase in body weight.

[However], eating out at fast-food restaurants and full-service restaurants seems to be the most important factor in explaining the rise in obesity.

...as much as two-thirds of the increase in adult obesity since 1980 can be explained by the rapid growth in the per capita number of fast-food restaurants and full-service restaurants, especially the former. It’s not hard to imagine how the explosive growth in these restaurants could fuel the obesity epidemic. Food served in these restaurants has extremely high caloric density, and almost certainly has contributed to obesity...

Indeed, the economists Patricia M. Anderson, Kristin F. Butcher, and Phillip B. Levine find that the rise in average hours worked by mothers can account for as much as one-third of the growth in obesity among children in certain families. In part, the rise in obesity seems to have been an unintended consequence of encouraging women to become more active in the workforce.

We have also unmasked a second and perhaps more surprising culprit in the alarming rise in obesity: the crackdown on smoking via tax increases. Higher cigarette taxes and higher cigarette prices have caused more smokers to quit — but these smokers seem to have begun eating more as a result. According to our research, each 10 percent increase in the real price of cigarettes produces a 2 percent increase in the number of obese people, other things being equal...

Our findings underscore the idea that social action can have unintended consequences: Oftentimes, there is a tradeoff involved in achieving goals that society favors, such as increased food production, more workforce participation by women, and fewer smokers. Lower real food prices have significantly increased living standards. Expanded labor market opportunities for women have increased families’ command of real resources and increased equality of opportunity. Cigarette smoking is still the largest cause of premature death among Americans; pushing smokers to quit will have obvious health benefits. But our results and those of other economists also suggest that these efforts contribute to the rising prevalence of obesity. Whether public policies should be pursued that offset this ignored consequence of previous public policy to discourage smoking, increase market opportunities, and make cheaper food available depends on the costs and benefits of these policies...

...the non-obese do subsidize the obese. Health and life insurance premiums paid by the latter do not fully reflect their higher medical care costs and their higher probability of death.

Their solutions?

Raising premiums for the obese could correct this externality, but would raise considerable equity concerns given that obesity has such a large genetic component. Imposition of taxes on “junk food,” fast food, or food with a high caloric content might be viewed as a substitute, since the consumption of these types of food is a conscious choice made by individuals. But this policy imposes costs on people who consume these types of food in moderation, too...

Giving benefits to people who exercise and subsidizing facilities and programs for them might be a more promising approach...

Would the people of the past, who toiled through their workdays and often did not have enough food, have predicted this problem? Would those who once dreamed of ending poverty and supplying enough food for all have even imagined that being too fat would become the predominant health risk nationwide?

The main message of contemporary research is that there is no free lunch, that with benefits come costs. Positive changes such as increases in technology, reduced smoking, and increased female participation in the labor force have also carried unforseen negative consequences. Was the anti-smoking campaign a mistake if it also encouraged obesity?

Murray also links to a profile of Soso Whaley, who

imposed a limit of 1,800 to 2,000 calories when she started her diet April 1. But her intake would increase up to 3,000 calories "when I gave myself the day off," she said.

She dropped 10 pounds from her 5-foot-3-inch frame in the first month of her experiment, slimming down to 165 from 175. Her cholesterol level fell to 197 from 237 by the beginning of May.

Like Mr. Spurlock, Ms. Whaley said she tried every item on the menu at least once. But she spent about an hour doing moderate exercise three times a week.

Although she did have salads, Ms. Whaley said she stuck with sandwiches, fries, diet sodas and shakes.

"I actually had a much tougher time when I got back in the real world [in May] because I was so used to controlled portion sizes" at the burger chain, she said.

But don't forget GINA KOLATA's The Fat Epidemic: He Says It's an Illusion

Dr. Jeffrey Friedman, an obesity researcher at Rockefeller University, argues that contrary to popular opinion, national data do not show Americans growing uniformly fatter.

Instead, he says, the statistics demonstrate clearly that while the very fat are getting fatter, thinner people have remained pretty much the same...

Dr. Friedman points to careful statistical analyses of the changes in Americans' body weights from 1991 to today by Dr. Katherine Flegal of the National Center for Health Statistics. At the lower end of the weight distribution, nothing has changed, not even by a few pounds. As you move up the scale, a few additional pounds start to show up, but even at midrange, people today are just 6 or 7 pounds heavier than they were in 1991. Only with the massively obese, the very top of the distribution, is there a substantial increase in weight, about 25 to 30 pounds, Dr. Flegal reported...

Over the years, Dr. Friedman says, he has watched the scientific data accumulate to show that body weight, in animals and humans, is not under conscious control. Body weight, he says, is genetically determined, as tightly regulated as height. Genes control not only how much you eat but also the metabolic rate at which you burn food. When it comes to eating, free will is an illusion.

"People can exert a level of control over their weight within a 10-, perhaps a 15-pound range," Dr. Friedman said. But expecting an obese person to decide to simply eat less and exercise more to get below the obesity range, below the overweight range? It virtually never happens, he said. Any weight that is lost almost invariably comes right back.

The same goes for gaining weight in general, Dr. Friedman argued. A person who has the genes to be thin is not going to get fat because portion sizes increase. It makes no scientific sense, he said.

But isn't it true that we can decide to eat or not, choosing to skip dinner, say, or pass up dessert? Isn't that free will? Not really, Dr. Friedman said. The control mechanisms for body weight operate over months, even years, not day to day or meal to meal.

"People live in the moment," he said. "They lose weight over the short term and say that they have exercised willpower," but over the long term, the body's intrinsic controls win out. And just as willpower cannot make fat people thin, a lack of it does not make thin people fat.

But a word of caution. As the article notes, Friedman discovered the gene for leptin, whose absence made mice grow massively obese. In other words, he wants to believe that genes are the culprit.