History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women, a study from researchers at the Fred Hutchinson Cancer Research Center, published in Metabolism, claims to have shown that people who "yo-yo diet" do not suffer any lasting metabolic changes as a result. That is, according to the study, if you diet then gain weight repeatedly, you will not find it more difficult to lose weight on subsequent diets.
The analysis aimed to determine whether women with a history of moderate or severe weight cycling were at a disadvantage compared to non-weight-cyclers when it came to losing weight. Of the study participants overall, 18 percent (77 women) met the criteria for severe weight cycling (having reported losing 20 or more pounds on three or more occasions) and 24 percent (103 women) met the criteria for moderate weight cycling (having reported losing 10 or more pounds on three or more occasions).
Although severe weight cyclers were, on average, nearly 20 pounds heavier than non-cyclers at the start of the study, at the end of the study the researchers found no significant differences between those who yo-yo dieted and those who didn't with regard to the ability to successfully participate in diet and/or exercise programs. The cyclers also did not differ from the non-cyclers with regard to the impact of diet or diet-plus-exercise on weight loss, percentage of body fat and lean muscle mass gained or lost. Other physiological factors such as blood pressure, insulin sensitivity, and blood concentrations of hormones such as leptin (which helps make one feel full) and adiponectin (which helps regulate glucose levels) also did not differ significantly among those whose weight fluctuated and those whose did not.
England's Football Association embodies the nation's most popular sport. To promote fitness and good health, it provides these splendid awards to schools that offer adequate soccer programs. I'd ask if you could spot the mistake, but I think this may be one of those "honor the error as a hidden intention" dealies—a tragic fact echoed by star player Rio Ferdinand's endorsement deal with a tobacco company. [via Ben Goldacre and Huw G] Read the rest
Read the rest
It seems that Burger King must have taken a very long position on pork futures, because they've rolled out a temporary Memphis Pulled Pork BBQ Sandwich, Carolina BBQ Whopper, Texas BBQ Whopper and a bacon sundae:
The AP reports that BK will launch the treat — which has fudge, caramel, crumbled bacon and a full piece of bacon — later this week, along with other limited time items.
It has 510 calories, 18 grams of fat and 61 grams of sugar, but we're guessing that these numbers won't discourage the bacon-curious from giving it a try.
At the NYT, Michael M. Grynbaum reports on Mayor Michael Bloomberg's plan to abolish sales of large bottles or cups of soda outside of grocery stores.
The proposed ban would affect virtually the entire menu of popular sugary drinks found in delis, fast-food franchises and even sports arenas, from energy drinks to pre-sweetened iced teas. The sale of any cup or bottle of sweetened drink larger than 16 fluid ounces — about the size of a medium coffee, and smaller than a common soda bottle — would be prohibited under the first-in-the-nation plan, which could take effect as soon as next March.
Presumably, refills and the purchase of multiple smaller sodas will also be banned, in order to demonstrate that this isn't empty hot air that just happens to increase the price- and profitability-by-volume of soda.
A study at MIT involving mice fed a diet of vanilla yogurt with probiotics yielded interesting and unanticipated results:
First, the scientists noticed that the yogurt-eating mice were incredibly shiny. Using both traditional histology techniques and cosmetic rating scales, the researchers showed that these animals had 10 times the active follicle density of other mice, resulting in luxuriantly silky fur.
Then the researchers spotted something particular about the males: they projected their testes outward, which endowed them with a certain “mouse swagger,” Erdman says. On measuring the males, they found that the testicles of the yogurt consumers were about 5 percent heavier than those of mice fed typical diets alone and around 15 percent heavier than those of junk-eating males.
More in SciAm. The fact that these manly-mouse-man results were achieved from girly-vanilla-yogurt is not lost on me.
But I want to know is, how exactly does one go about weighing the mice's testicles? Your thoughts in the comments. (via Ed Yong)
Former Boing Boing guestblogger and all-round* happy mutant Craig Engler sez,
Weighthacker.com is a new site for geeks who want to lose weight and get fit. It takes the latest science and research about nutrition and weight loss and translates it into practical, daily advice that geeks can incorporate into their existing lifestyles.
Things like playing games, a love of gadgets and surfing the Web are often seen as contributing to a sedentary, unhealthy existence. But with Weighthacker, those geeky passions can be used as the foundation of a healthy life. Weighthacks aren’t short cuts, they’re smart cuts. They’re the smartest, most optimal things people can do to lose weight.
I’m also crowdfunding a how-to book called “Weight Hacking: A Guide For Geeks Who Want To Lose Weight And Get Fit.” The book will be a complete operating system for nerds who want to lose weight and get healthier. It will include stories of celebrity geeks who’ve lost weight, like beloved author Neil Gaiman and BoingBoing editor Cory Doctorow. And Bonnie Burton, who wrote the Star Wars Craft Book, will be creating new healthy “Food Crafts” for Weight Hacking.
*Actually, a lot less round, these days
When the Tokyo Burger King stores announced a "15 strips of bacon on your burger for ¥100 (~$1.25)" promotion, Mr Sato, a reporter for Rocket News 24 ordered 105 slices of bacon on his burger. Apparently, Mr Sato ate the "grotesque agglomeration of ketchup-soaked meat about 3 times the size of the regular whopper" and then rushed home to recuperate.
To see how far they could push it, the newsroom sent Mr Sato back to order a burger with 1,050 slices of bacon. 2 hours later, the 2.7kg treat was presented to him, with an estimated caloric load of 14,300.
Before going to work on the burger, Mr. Sato once again began his primal ritual of psyching himself up, shouting: “This is what real hamburger lovers eat! 10 strips? 100 strips? Like that’s enough! A real man needs 1050 strips of bacon!”
Mr. Sato then plunges his face into the top of the burger, holding on to the top bun and a layer of bacon below the beef patty for support. Eventually he runs out of burger to supplement his bacon and simply begins stuffing bacon into his mouth by the fistful, all the while ranting: “Delicious! This is what meat is all about! This is the taste of a real hamburger!”
But you’re only eating bacon…
In any case, thanks to Mr. Sato’s gluttony, we have learned that there is seemingly no limit to the amount of bacon you can add to a Whopper. Or maybe it’s because this is Japan and they’re just that dedicated to their customers; we’re not sure if we could walk into a Burger King in America and expect the same level of service…
We've had a couple of posts recently about a hypothesis that links the current increase in obesity with an increase in easy access to foods that are designed to trigger reward systems in the human brain. Basically: Maybe we're getting fatter because our brains are seeking out the recurrent reward of food that makes us fat. Scientist Stephan Guyenet explained it all in more detail in a recent guest post.
It's an interesting—and increasingly popular—idea, though not without flaws. To give you some context on how scientists are talking about this, I linked you to a blog post by Scicurious, another scientist who wrote about some of the critiques of food reward and related ideas. In particular, Scicurious questioned some of the implicit connections being made here between body size and health, and eating patterns and body size.
She also talked about another critique, one which came up in a recent article in the journal Nature Reviews Neuroscience. If people are gaining weight because they're addicted to eating unhealthy foods, we ought to see some evidence of that in the way their brains respond to those foods. After all, brains respond to many physically addictive substances in special ways. But we don't see that with junk food. So does that invalidate the hypothesis?
Stephan Guyenet doesn't think it does. In a recent email to me, he explained that he thinks the food reward hypothesis is a bit more nuanced, and can't really be described as "food addiction". At least, not the same way that cigarettes or heroin are addictive.
Addiction is the dependence on a drug, or behavior, despite clear negative consequences. Drug addiction is associated with characteristic changes in the brain, particularly in regions that govern motivation and behavioral reinforcement (reward), which drive out-of-control drug seeking behaviors. Some researchers have proposed that common obesity is a type of “food addiction”, whereby drug addiction-like changes in the brain cause a loss of control over eating behavior. Hisham Ziauddeen and colleagues recently published an opinion piece in Nature Reviews Neuroscience reviewing the evidence related to this idea.
The review concluded that there is currently not enough evidence to treat obesity as a “food addiction”. I agree, and I doubt there ever will be enough evidence. However, this does not challenge the idea that food reward is involved in obesity, an idea I described in a review article in JCEM, on my blog (1, 2), and my recent Boing Boing piece.
The reward system is what motivates us to seek and consume food, and what motivates us to choose certain foods over others. To begin to appreciate its role in obesity, all we need is a common sense example.
Why do some people drink sweetened sodas between meals, rather than plain water? Is it because sodas quench thirst better than water? Is it because people are hungry and need the extra calories? If so, why not just eat a plain potato or a handful of unsalted nuts? The main reason people drink soda is that they enjoy it, plain and simple. They like the sweetness, they like the flavor, they like the feeling of carbonation on the tongue and the mild stimulation the caffeine provides. It’s the same reason people eat a thick slice of double chocolate cake even though they’re stuffed after a large meal. The reward system motivates you to seek the soda and cake, and the hedonic (pleasure) system encourages you to keep consuming it once you’ve begun.
But is this the same as addiction? If I took a person’s cola away, would they get the shakes? Would they break into a convenience store at night to get a cola fix? I’m going to say no.
I agree with Ziauddeen and colleagues that the evidence at this point is not sufficient to say that common obesity represents food addiction, and I appreciate their skeptical perspective on the matter. In obesity, as in leanness, the food reward system appears to be doing exactly what it evolved to do: seek out energy-dense, tasty food, and strongly suggest that you eat it. The problem is that we’re increasingly surrounded by easily accessible, cheap, commercial food that is designed to hit these circuits as hard as possible, with the goal of driving repeat purchase and consumption behaviors. Our brains are not malfunctioning; they’re reacting just as they’re supposed to around foods like this.
We recently hosted an article by scientist and guest blogger Stephan Guyenet that explained how certain foods—those with a high calorie density, fat, starch, sugar, salt, free glutamate (umami), certain textures (easily chewed, soft or crunchy, solid fat), certain flavors, an absence of bitterness, food variety, and drugs such as alcohol and caffeine—could trip reward systems in the human brain. Those reward systems, then, encourage people to eat more of the foods that trigger the reward. The result, says Guyenet, is a cycle that could be the link between the American obesity epidemic and the rise of highly processed convenience foods, designed specifically to trip those neural reward systems.
This theory, and several related theories, are increasingly popular in the scientific community. This week, there's an opinion piece in the journal Nature Reviews Neuroscience that looks at the strengths and weaknesses of these theories and talks about what research needs to be done going forward. It's kind of a space for researchers to step back and say, "Okay, here's what we know, here's what's not lining up with what we think we know, and here's what we have to do if we want to understand this better." In the context of science, an article like this isn't really a slam against the ideas it analyzes. Instead, it's meant to summarize the state of the science and share ideas that could either strengthen the case, or lead down entirely new roads.
Sadly, you can't read this article unless you have a subscription to Nature Reviews Neuroscience (or pay them $32 for single article access).
Luckily, Scicurious, a neuroscientist and an excellent blogger, has read the article, and has a nice run-down of what it's saying and what you should know. Some of the ideas being discussed here overlap with Stephan Guyenet's research. Some don't. But this is connected enough that I thought you guys would be interested in reading more and getting more perspectives on this issue. Let me make this clear, though: Guyenet isn't doing bad science. As with a lot of scientific research, there's often more than one way to look at the same data. Scientists can disagree without one person having to be all-wrong and another all-right. In fact, having different scientists working on the same subject is a key part of getting the facts right.
As you read, you'll notice that an important place where Scicurious' perspective really differs from Guyenet's is in terms of connecting the idea of "addiction" to certain foods back to the idea of an obesity epidemic.
...is there a place for food addiction? The authors think so, and I am inclined to agree. However, it needs to be much more stringent than the current model of food addiction that many people want to embrace (the idea that sugar makes you addicted or that being overweight means you have a problem). Changes need to be made.
First off, it's important to separate food addiction from obesity. Binge eating does not necessarily mean you are overweight, and being overweight does not necessarily mean that you binge eat. Ranking by BMI is not going to work.
Let me preface anything else in this post by clarifying something important. What we are talking about here is a hypothesis—it's not been proven. In fact, it's not even really been tested yet. The studies that will put the hypothesis to the test are currently underway. So please (please, please, please) do not walk away assuming this is a given. It's not. It could very well be completely and utterly wrong. But it's interesting. And it will be in the news. And I want you guys to hear about it in the proper context.
Make sense? Okay, then ...
This idea is (for now) based on "what if" extrapolation rather than data. But it's not totally crazy. We know air pollution affects health in ways would not have been obvious just a few decades ago. For instance, there is a strong, well-documented connection between air pollution and heart disease. In 2009, Aruni Bhatnagar, professor of medicine at the University of Louisville, told me that studies from 250 different metropolitan areas in the United States showed that a spike in air pollution was reliably followed by a spike in cardiac deaths within next 24-48 hours. The people primarily at risk are those who already have underlying heart health problems, but it's not always clear who those people are. We don't yet know exactly how pollution affects the heart—it could well be a cascade of effects that actually starts in the lungs—but we can see that the affect is there.
This new hypothesis, proposed by Arne Astrup, head of the department of obesity and nutrition at the University of Copenhagen, does not come with that kind of supporting evidence. Instead, it's more of an extrapolation.
At Discovery News, Emily Sohn explains why this hypothesis could make sense—and why it's way too early to say whether or not it's actually right.
The idea proposes that breathing in extra CO2 makes blood more acidic, which in turn causes neurons that regulate appetite, sleep and metabolism to fire more frequently. As a result, we might be eating more, sleeping less and gaining more weight, partly as a result of the air we breathe.
...Obesity and its associated health risks have escalated dramatically in the last few decades. And even though just about everyone thinks the reason is obvious -- we are eating too many calories and exercising too little -- research has revealed that obesity is far more complex than that, with multiple genes, metabolic pathways and even gut microbes involved, said obesity researcher David Allison, director of the Nutrition Obesity Research Center at the University of Alabama at Birmingham.
The New York Times has a fascinating story about the current state of the science on weight loss, including the results of one recent (albeit small) study that suggests that the human body responds to weight loss by actively trying to regain weight—a finding that could help explain why it's so difficult to maintain significant weight loss, even when you are able to shed pounds.
I talk a lot about the importance of context in understanding science. The results of one, single research paper do not tell you everything you need to know on a given subject. Instead, you have to look at how those results fit into the big picture. How do they compare to the results of other studies on the same subject? Have the results been independently verified? How do the specific experiments being done influence what you can and cannot say about the results? What questions aren't answered by the study, and what new questions does it bring up?
You should be thinking about that every time you see anybody talk about the results of a single, new study. Without context, you get situations like this one, described by Travis Saunders on the Obesity Panacea blog:
Earlier this year my friend and colleague Valerie Carson published an interesting paper examining the health impact of various types of sedentary behaviour in a sample of 2500 children and adolescents. They created a clustered risk score (CRS) which took into account a child’s waist circumference, blood pressure, cholesterol, and inflammation, and then examined whether it was associated with 3 different measures of sedentary behaviour – accelerometry (an objective measure of movement), self-reported TV watching, and self-reported computer use.
Here is what they found (emphasis mine): For types of sedentary behavior, high TV use, but not high computer use, was a predictor of high CRS after adjustment for MVPA and other confounders. Here is what the Daily Mail had to say: Watching TV most damaging pastime for inactive children, increasing risk of heart disease.
Last month, our group in Ottawa published another paper (led by Dr Gary Goldfield) looking at different types of sedentary behaviour and heart disease risk factors in a cohort of overweight and obese teens (in contrast, the earlier study was on a sample of nationally representative youth). Interestingly, we found that neither TV time nor computer time was associated with increased risk in this group - in our dataset it was video games that were by far the most important sedentary behaviour.
Why is this a problem? Put yourself in the shoes of someone who just read the Daily Mail article, and who now believes that TV viewing is the single most damaging sedentary behaviour for kids to engage in. What reaction are you going to have when you read a similar article about our new study, suggesting that TV viewing and computer use aren’t important at all, but that video games are actually “the most damaging activity an inactive child can indulge in”?
As the source of this problem, Saunders rightly calls out journalists for pushing every individual study as a "GROUNDBREAKING NEW FINDING". It is, unfortunately, rare to find TV and newspaper coverage that treats new studies in context, rather than as the final word. But to that, I'd add university PR people. The sad truth is, with newspaper layoffs, many of the people writing about science aren't specialists. They cover city council one day, school board the next, and a new research finding after that. The press releases they get (and I know, because I get those press releases, too) push GROUNDBREAKING NEW FINDINGS not research that fits into a larger context. It's the journalists job to know better. But it's also the university's job to not manipulate journalists.