Obesity and Heart Disease
purepedantry | December 17, 2008I have been meaning to talk about this story, but I have been busy.
A study in Nature looked for genes linked with "common" obesity (more on that in a moment), and it was one of the first to link genes to the disease. Turns out several are genes expressed in the brain:
A genetic study of more than 90,000 people has identified six new genetic variants that are associated with increased Body Mass Index (BMI), the most commonly used measure of obesity. Five of the genes are known to be active in the brain, suggesting that many genetic variants implicated in obesity might affect behaviour,…
purepedantry | October 31, 2008This Sunday you are slightly less likely to have a heart attack.
Swedish researchers, publishing in the NEJM, looked at a registry of heart attacks from 1987 to 2006. They found that the incidence of heart attacks slightly increases for the three days following the Spring daylight savings time where we lose an hour. The incidence of heart attacks slightly decreased on the day after Fall daylight savings time:
We used data from the Swedish registry of acute myocardial infarction, which provides high-quality information on all acute myocardial infarctions in the country since 1987. The…
purepedantry | August 20, 2008The fit-fat fight -- whether someone can be obese but still healthy -- has reignited (if it ever really stopped) with an article in the Archives of Internal Medicine that was reported in the NYTimes.
Wildman et al. used data from the NHANES study and looked at the relationship between Body Mass Index (BMI) and whether the individuals had a variety of other indicators of cardiovascular risk -- mostly blood tests that indicate poor cardiometabolic physiology like high cholesterol or high blood pressure. What they found was that large numbers of obese individuals (BMI > 30) had few…
purepedantry | August 1, 2008There is an interesting discussion going on at the Becker-Posner blog about obesity abatement. Richard Posner talks about the NY ordinance requiring that calorie counts of food be prominently labeled fast food restaurants:
The significance of the New York City ordinance lies in its requiring that calorie numbers be printed next to the food items on menus and menu boards and in large type. The purpose is less to inform than to frighten. Psychologists have shown (what is anyway pretty obvious) that people respond more to information that is presented to them in a dramatic, memorable form than…
purepedantry | June 3, 2008It has become almost the conventional wisdom that the obesity epidemic is at least partially attributable to people eating out. I for one really try and avoid eating out because I always feel like I end up eating junk food. But does this really matter? Do people actually eat more overall when they eat out more?
Economists Michael Anderson and David A. Matsa from UC Berkeley and Northwestern University respectively say no. In a working paper published last year, they argue that when people eat out they eat less at home -- resulting in only a tiny net gain in caloric intake.
To analyze the…
purepedantry | December 6, 2007Now that is pretty clear. This is from Miller and Silverstein in Nature Clinical Practice. It is in reference to childhood obesity:
There has been much debate about the cause of the current epidemic of obesity. Most experts agree that the increased prevalence of childhood obesity cannot be blamed on changes in either the environment or genetics alone. Environmental changes (i.e. nutrition and lifestyle) are, however, likely to be primarily responsible for the current epidemic, because it is not possible for the gene pool to change in less than one generation.
The authors go on to present…
purepedantry | September 26, 2007Castro's Cuba has seen a precipitous drop in obesity rates and in the deaths associated with cardiovascular risk:
Cuba's economic crisis of 1989-2000 resulted in reduced energy intake, increased physical activity, and sustained population-wide weight loss. The authors evaluated the possible association of these factors with mortality trends. Data on per capita daily energy intake, physical activity, weight loss, and smoking were systematically retrieved from national and local surveys. National vital statistics from 1980-2005 were used to assess trends in mortality from diabetes, coronary…
purepedantry | May 17, 2007Not good news for people who think low carbs is the answer. A recently published study has shown an increase in mortality associated with low-carb/high-protein diets.
Studies looking at the comparative effectiveness of different diets have shown that basically all diets are equivalent. (Equivalently bad, that is. All the diets tested produced moderate declines in weight, but adherence was low.) However, no real studies have examined what the mortality benefits or hazards might be associated with the low-carb/high-protein diets that are currently de rigeur.
Trichopoulou et al.,…
purepedantry | May 10, 2007The NYTimes ran an excerpt of a book called Rethinking Thin: The New Science of Weight Loss -- and the Myths and Realities of Dieting by Gina Kolata. Having read the excerpt -- I haven't read the whole book -- I take issue with how Kolata frames the issue of the genetics of obesity.
My problem with most articles and books discussing genetics -- particularly with respect to behavior -- is that they don't emphasize the concept of an environmental X genetic interaction in determining outcome. It's either all genetics or all environment.
Before, I talk about the genetics of obesity and the…
purepedantry | April 30, 2007If this works, this guy is going to make a bagillion dollars:
By giving ordinary adult mice a drug - a synthetic designed to mimic fat - Salk Institute scientist Dr. Ronald M. Evans is now able to chemically switch on PPAR-d, the master regulator that controls the ability of cells to burn fat. Even when the mice are not active, turning on the chemical switch activates the same fat-burning process that occurs during exercise. The resulting shift in energy balance (calories in, calories burned) makes the mice resistant to weight gain on a high fat diet.
The hope, Dr. Evans told scientists…
purepedantry | April 10, 2007If you don't want to overeat, make sure they don't bus your table:
People watching the Super Bowl who saw how much they had already eaten -- in this case, leftover chicken-wing bones -- ate 27 percent less than people who had no such environmental cues, finds a new Cornell study.
The difference between the two groups -- those eating at a table where leftover bones accumulated compared with those whose leftovers were removed -- was greater for men than for women.
"The results suggest that people restrict their consumption when evidence of food consumed is available to signal how much food they…
purepedantry | April 2, 2007This article struck my eye because all of the literature I was familiar with said the opposite. The authors looked a weight gain in the mother during pregnancy and found that the children of the mothers who gained too much or even normal amounts of weight -- by the existing standards -- were more likely to be overweight at 3 years old:
Pregnant women who gain excessive or even appropriate weight, according to current guidelines, are four times more likely than women who gain inadequate weight to have a baby who becomes overweight in early childhood. These findings are from a new study at the…
purepedantry | February 5, 2007After surveying parents of overweight children researchers found that the majority are not even aware their child is overweight:
Researchers with Deakin's Centre for Physical Activity and Nutrition Research surveyed more than 1200 families to find out if parents had concerns about their children's weight and if they took any preventative action to avoid obesity in their children.
The study of more than 1100 families found that 89 per cent of parents of overweight 5--6 year-olds and 63 per cent of parents of overweight 10--12 year-olds were unaware their child was overweight. It also revealed…
purepedantry | January 12, 2007Greg Beato in Reason:
"It will take a grassroots effort of doctors, community leaders and consumers to force the government and the food industry to get those sugary foods out of mainstream American diets" [Robert] Lustig [of UCSF] told the San Francisco Chronicle. "Everyone's assuming you have a choice, but when your brain is starving, you don't have a choice.... Congress says you can't sue McDonald's for obesity because it's your fault. Except the thing is, when you don't have a choice, it's not your fault."
...
...forget "starving brains" and the notion that we have "no choice" in the…
purepedantry | January 10, 2007I knew the children were up to something -- with their beady little eyes:
Adults who live with children eat more fat, and more saturated fat, than those who do not, according to a new study.
The report, published online last week in The Journal of the American Board of Family Medicine, was based on data from the Third National Health and Nutrition Survey, a six-year nationwide study of more than 33,000 people carried out by the Centers for Disease Control and Prevention.
According to background information in the article, the correlation between adults' and children's diets has usually been…
purepedantry | December 20, 2006This is never going to end:
A lawmaker introduced a bill on Tuesday that would make Massachusetts the first U.S. state to ban artificial trans fats from restaurants, closely following New York City's ban of the artery-clogging oils.
"We have an opportunity to vastly improve public health by directing restaurants to switch to healthier alternatives," Peter Koutoujian, a Democratic representative in the Massachusetts Legislature, said in a statement.
The bill uses language similar to new regulations announced this month by New York City, but marks the first effort to force restaurants in an…
purepedantry | December 19, 2006I wrote before about how I think the NY trans-fat ban is scientifically supportable but not particularly the government's business. Here is interesting speculation in Free Exchange:
Banning trans fats in restaurants, but not in grocery stores, doesn't make sense. I guess the supermarket lobby is more powerful than the fast-food and donut lobby.
I'd guess that it has more to do with public choice theory than ardent lobbying. Since national food producers are unlikely to reformulate their entire line for the benefit of a few million New Yorkers, a trans-fat ban would sweep large categories…
purepedantry | December 6, 2006Yesterday, the NY Board of Health voted to ban trans fats -- after a phase-out period -- in restaurants in the city:
New York City's board of health on Tuesday voted to phase out most artificial transfats from restaurants, forcing doughnut shops and fast-food stands to remove artery-clogging oils from their cooking.
The law will require McDonald's and other fast-food chains that have not already eliminated transfats to do so by July 2007. They will be given a six-month grace period before facing fines.
Makers of doughnuts and other baked goods will be given until July 2008 to phase out…
purepedantry | November 17, 2006The most commonly cited causes of the obesity epidemic over the last 30 years are decreases in physical activity and increased consumption of unhealthy foods: the Big Two. For these as causes, we have what can only be described as an overwhelming quantity of evidence.
However, many other causes of increased obesity have been suggested such as environmental endocrine disruptors or chronic sleep deprivation. In an editorial in the International Journal of Obesity, Keith et al. argue that for some of them the evidence is quite solid -- meriting further study and possibly public health…
purepedantry | August 21, 2006BMI or Body Mass Index is a measure of obesity that is used to approximate the health problems associated with being overweight. It is really easy to calculate. The formula for it is weight in kilograms divided by height in meters squared. Here are some calculators for those of your reluctant to mosey into the metric system. Anyway, after you calculate it values below 20 are generally considered underweight. Values between 20 and 25 are considered normal weight. Over 25 is considered overweight. Over 30 is considered obese (with various classes of obese determined by how large the…