CLA, or conjugated linoleic acid, is the “good” trans-fat that occurs naturally in meat and dairy, especially from grass-fed animals. In the stomach of ruminants like cows, sheep, or goats, millions upon millions of bacteria help the animal digest its food. They also help convert dietary grass-based linoleic fatty acids into saturated fatty acids. Well, that conversion takes several steps, and one of the steps is the creation of CLA, some of which never gets fully saturated and instead shows up in the animal’s body and milk fat.
Twenty-eight different CLA isomers, or structural arrangements of the molecules, appear in CLA-rich animal fat. It’s very complex and quite different from trans-fat created by partially hydrogenating vegetable oils. Those lab-created trans-fats have definite negative metabolic and health effects, while the panoply of various CLA isomers from grass-fed dairy and meat seem to be beneficial.
What about CLA supplements? Is synthetic CLA just as good for you as naturally-occurring CLA?
Read MoreWeight Watchers (recently rebranded to WW) put out an app for kids and teens who want to lose weight a few months ago. It’s called Kurbo, and it assigns “traffic light” color codes to different foods. Green foods like fruits and vegetables can be eaten freely, yellow foods like low-fat dairy, lean meat, and bread can be eaten in moderation, and red foods like full-fat dairy and sweets should be eaten sparingly or “planned for.” Kids under 13 need to sign up with a parent, while older kids can sign up on their own. Online coaching is available for an extra fee. Users are urged to track their food intake and body weight, even if they choose a goal like “Have more energy.”
Critics hit back. The Atlantic claimed that using apps like Kurbo won’t make a difference for the kids who need it most—those living in “food deserts,” those exposed to junk food marketing, those whose parents can’t afford healthy food and haven’t the time to fix healthy meals. Outside Online warned against the potential for Kurbo to create unhealthy fixations on food and “clean eating” in kids, setting the stage for eating disorders that can increase the risk of mortality, depression, and anxiety later in life. They called for an overhaul of “food policy” instead.
Read MoreFor today’s edition of Dear Mark, I’m answering one question from a reader. It concerns the effects of physical activity on obesity.
This is an evergreen topic, a constant in the queries I receive. Is exercise necessary for weight loss? Does physical activity improve body weight? Is exercise all about burning calories, or is there something else going on?
Let’s get to it:
Read MoreMetabolic flexibility is the capacity to match fuel oxidation to fuel availability—or switch between burning carbs and burning fat. Someone with great metabolic flexibility can burn carbs when they eat them. They can burn fat when they eat it (or when they don’t eat at all). They can switch between carbohydrate metabolism and fat metabolism with relative ease. All those people who can “eat whatever they want” most likely have excellent metabolic flexibility. So, why does it really matter, and how does it happen? Let’s get into the weeds today.
Read MoreFor today’s Dear Mark, I’m answering just one question from a reader. What are we to make of the new study purporting to show that saturated fat is the most harmful substance a liver can encounter? Should we remove all traces of it from our diets? Should we eat pure sugar? Quaff soybean oil? How relevant is an overfeeding study to a community of people dedicated to eating a sustainable, weight-reducing or -maintaining diet that includes saturated fat?
Let’s find out:
Read MoreInsulin does a lot of important things for us. It pulls glucose from the blood and fritters it away into our cells to be burned for energy or stored as glycogen. It prevents hyperglycemic toxicity to neurons, pancreatic cells, the arterial walls and the generation of excessive levels of reactive oxygen species. It even promotes muscle protein synthesis and helps augment muscular hypertrophy, especially following resistance training. Clearly, we need insulin. Without it, we’d die, as type 1 diabetics readily do without an exogenous source.
But this process goes off the rails when our cells become resistant to the effect of insulin over time. We secrete too much. Our levels remain elevated. It becomes harder to burn body fat. In fact, we end up in even more efficient fat storage mode.
I’ve shared about nutritional means to enhance insulin sensitivity in the past. What about other non-dietary strategies?
Read MoreThis is an updated version of a Dear Mark column from 2012. You can find the original version archived here. The below has been completely updated for 2018.
The blank slate hypothesis has fallen. Everyone comes into this world imbued with attributes, characteristics, and predilections that are uniquely theirs. We’re all humans, but we’re a diverse bunch, and that makes it interesting. And though it also makes giving cookie cutter health advice impossible, I just take that as an opportunity to stand out from the crowd and provide actionable advice that genuinely helps real people.
A perfect example is biological sex. Anyone who’s lived with the opposite sex, been married, or had kids of different sexes knows that males and females are different—on average.
There’s a ton of overlap, don’t get me wrong.
Read MoreFor today’s edition of Dear Mark, I’m not so much answering a direct question as I am riffing on an offhand comment. In the comments from last week’s post on weight loss culture, someone mentioned obesity being a “first world problem.” It made me think more deeply about the issue.
In a literal sense, yes. Obesity is often a first-world problem. If your primary concern is figuring out how to stop yourself from eating too much food, you’ve got the kind of problems starving kids in developing countries would love to have.
Yet, industrial food has a long reach. The island nations of Nauru, Micronesia, Tonga, Cook Islands, and Niue are the top 5 fattest countries in the world—even though they aren’t “first world”—because they rely almost entirely on imported, industrial food.
Read MoreI recently read a piece from the New York Times in which the author, Taffy Brodesser-Akner, recounts her lifelong struggle with dieting and body acceptance and her relationship to food. She tackles the failure of most “diets,” the fat acceptance movement, the Weight Watchers-as-support-group phenomenon, the Oprah Winfrey body weight yo-yoing. What makes it an effective article is that, rather than cast herself as dispassionate journalist reporting the facts, Akner is elbows deep. She herself is the subject as much as anything else. It’s a powerful article. Go read it.
The article doesn’t come to a neat conclusion. There’s no prescription at the end. It meanders. It explores. It’s messy. I think that’s exactly how most people feel when trying to tackle this diet/health/bodyweight/eating thing: confused, lost, conflicted, overwhelmed. Go look at the comment section from the article, and you’ll see that pretty much everyone got something different from it.
Read MoreNote: Many of you have written to me wondering about my newfound obsession with CrossFit. I’m responding to a steady stream of requests from CFers who want to do Primal but have been led to believe that the two are incompatible. Even if you have no interest in CrossFit, understand that much of the advice contained in this series also applies to people following a different training path.
As much as CrossFitters claim to concern themselves primarily with increasing physical performance and work capacity across broad modal domains, they also want to lose body fat. There’s nothing wrong or superficial about that, mind you. Excess body fat is unnecessary and, depending on the quantity and location, dangerous to your long-term health. It also impedes performance, acting as dead weight. We have every reason to want to lose body fat.
CrossFit is well-known for leaning people out. But there’s also a small but significant portion of people who struggle to lose body fat despite—or perhaps because of—hitting the box religiously and doing all the workouts. This post is for them.
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