Check It Out: Good Calories, Bad Calories

If the members of the American medical establishment were to have a collective find-yourself-standing-naked-in-Times-Square-type nightmare, this might be it. They spend 30 years ridiculing Robert Atkins, author of the phenomenally-best-selling ''Dr. Atkins' Diet Revolution'' and ''Dr. Atkins' New Diet Revolution,'' accusing the Manhattan doctor of quackery and fraud, only to discover that the unrepentant Atkins was right all along. Or maybe it's this: they find that their very own dietary recommendations -- eat less fat and more carbohydrates -- are the cause of the rampaging epidemic of obesity in America. Or, just possibly this: they find out both of the above are true.

So begins Gary Taubes' thought-provoking and spectacularly polarizing July 2002 cover article for the New York Times Magazine entitled "What If It's All Been a Big Fat Lie?" Taubes, an award-winning science journalist, points out that well into the 1970s, the scientific consensus was that diets high in "sugars and starches" -- in other words, carbs -- caused obesity. Up until that point, "the accepted wisdom was that fat and protein protected against overeating by making you sated, and that carbohydrates made you fat." Thirty years ago,

you could still find articles in the journals describing high rates of obesity in Africa and the Caribbean where diets contained almost exclusively carbohydrates. The common thinking, wrote a former director of the Nutrition Division of the United Nations, was that the ideal diet, one that prevented obesity, snacking and excessive sugar consumption, was a diet ''with plenty of eggs, beef, mutton, chicken, butter and well-cooked vegetables.'' This was the identical prescription Brillat-Savarin put forth in 1825.

But over the past three decades, "we've been told with almost religious certainty by everyone from the surgeon general on down, and we have come to believe with almost religious certainty, that obesity is caused by the excessive consumption of fat, and that if we eat less fat we will lose weight and live longer."

What explains the shift in conventional wisdom? In 1977, "a Senate committee led by George McGovern published its 'Dietary Goals for the United States,' advising that Americans significantly curb their fat intake to abate an epidemic of 'killer diseases' supposedly sweeping the country," and "peaked in late 1984, when the National Institutes of Health officially recommended that all Americans over the age of 2 eat less fat." But according to Taubes, the reported increase in heart diseases that triggered these conclusions was wrong, and there was (is) no evidence to support the hypothesis that consumption of meat and dairy products had led to a dramatic uptick in heart disease. In the 1980s, the N.I.H. spent hundreds of millions of dollars trying -- and failing -- to link fatty diets with heart disease, but on a "leap of faith," posited nonetheless that the link existed. And "once the N.I.H. signed off on the low-fat doctrine, societal forces took over":

The food industry quickly began producing thousands of reduced-fat food products to meet the new recommendations. Fat was removed from foods like cookies, chips and yogurt. The problem was, it had to be replaced with something as tasty and pleasurable to the palate, which meant some form of sugar, often high-fructose corn syrup. Meanwhile, an entire industry emerged to create fat substitutes, of which Procter & Gamble's olestra was first. And because these reduced-fat meats, cheeses, snacks and cookies had to compete with a few hundred thousand other food products marketed in America, the industry dedicated considerable advertising effort to reinforcing the less-fat-is-good-health message. Helping the cause was what Walter Willett calls the ''huge forces'' of dietitians, health organizations, consumer groups, health reporters and even cookbook writers, all well-intended missionaries of healthful eating.

The message was loud and clear: Go low-fat. Eat carbs instead. For decades, this mantra was pounded into our heads by academics, health professionals, agribusiness and marketers alike. But these days, it's become widely accepted that carbs spike insulin production, which in turns triggers weight gain. And "[f]ew experts now deny that the low-fat message is radically oversimplified."

If nothing else, it effectively ignores the fact that unsaturated fats, like olive oil, are relatively good for you: they tend to elevate your good cholesterol, high-density lipoprotein (H.D.L.), and lower your bad cholesterol, low-density lipoprotein (L.D.L.), at least in comparison to the effect of carbohydrates. While higher L.D.L. raises your heart-disease risk, higher H.D.L. reduces it...

But it gets even weirder than that. Foods considered more or less deadly under the low-fat dogma turn out to be comparatively benign if you actually look at their fat content. More than two-thirds of the fat in a porterhouse steak, for instance, will definitively improve your cholesterol profile (at least in comparison with the baked potato next to it); it's true that the remainder will raise your L.D.L., the bad stuff, but it will also boost your H.D.L. The same is true for lard. If you work out the numbers, you come to the surreal conclusion that you can eat lard straight from the can and conceivably reduce your risk of heart disease.

I'm not saying you should immediately run screaming from carbs and start stocking up on lard. But it's worth checking out Taubes' claims for yourself.

I've just begun reading Taube's 2007 book, Good Calories, Bad Calories, and will post a review when I'm done. So far, I'm finding it an engaging read. If nothing else, it encourages intellectual curiosity: Taubes challenges readers to look askance at conventional wisdom and to question whether there's evidence to support what many of us have been taught about diet and nutrition. A healthy dose of skepticism is always a good thing. (It certainly helped color my reading of the New York Times' recent article on the "obesity-hunger paradox.")

Just like his controversial New York Times Magazine article, the talking heads are split on Taube's book. (Michael Pollan and Andrew Weil are fans; Jillian Michaels and Mehmet Oz are not.) And not all reviewers agree with Taube's conclusions. But regardless of where you land on this issue, there's certainly a lot of food for thought here.

After the jump: Video of Taube's 2007 lecture at U.C. Berkeley (in case you don't feel like reading his 468-page book, but want to get the gist of what he's saying).

P90X Day 84: X Stretch

Stretching feels damn good. I woke up feeling a little achy and creaky, and was happy that X Stretch was scheduled for today.

But does stretching actually do any good? I dug up yet another New York Times piece by Gina Kolata, concluding that "[t]he truth is that after dozens of studies and years of debate, no one really knows whether stretching helps, harms, or does anything in particular for performance or injury rates." Yes, stretching can make you more flexible, but there's no evidence of its benefits.

As I've mentioned before, Kolata also recently wrote an article explaining that cool-downs are unnecessary. Assuming her reporting is accurate, by skipping both X Stretch and our daily cool-downs during P90X, we could save an hour-and-a-half per week -- almost 20 hours over the course of a single round of P90X -- without adversely affecting our overall athletic performance.

Like I said earlier, stretching feels damn good. But sleeping in feels even better.

Cool Down? No, Thanks.

By the end of each morning's workout, I'm not just exhausted -- I'm in a mad rush. The kids are up and require feeding and changing, I need a protein shake and a shower, my hour-long freeway commute beckons, and my Blackberry is buzzing with work emails. Every minute -- every second -- counts.  But as I near the end of my first round of P90X, it's become increasingly difficult to drag my butt out of bed to squeeze in an hour-and-a-half of Tony Time before the day's craziness commences.  How, then, can I reduce my workout time?

Cut out the cool-down.

I warm up without fail, but by immediately turning off the DVD player when the cool-down starts, I save about five minutes every morning (30 minutes each week!) -- enough time to make my shake and get the kids dressed, or to quickly jump in and out of the shower. And according to the experts, this is perfectly fine because cool-downs are an utter waste of time.

As Gina Kolata wrote in the New York Times last week:

[T]he cool-down is enshrined in training lore. It’s in physiology textbooks, personal trainers often insist on it, fitness magazines tell you that you must do it -- and some exercise equipment at gyms automatically includes it. You punch in the time you want to work out on the machine and when your time is up, the machine automatically reduces the workload and continues for five minutes so you can cool down.

The problem, says Hirofumi Tanaka, an exercise physiologist at the University of Texas, Austin, is that there is pretty much no science behind the cool-down advice.

It's not even clear "what the cool-down is supposed to do," writes Kolata.  "Some say it alleviates muscle soreness. Others say it prevents muscle tightness or relieves strain on the heart." But actually,

Exercise researchers say there is only one agreed-on fact about the possible risk of suddenly stopping intense exercise. When you exercise hard, the blood vessels in your legs are expanded to send more blood to your legs and feet. And your heart is pumping fast. If you suddenly stop, your heart slows down, your blood is pooled in your legs and feet, and you can feel dizzy, even pass out. 

But does it matter for the ordinary, average athlete? “Probably not a great deal,” Dr. Thompson said. And, anyway, most people don’t just stand there, stock still, when their workout is over. They walk to the locker room or to their house or car, getting the cool-down benefit without officially “cooling down.”

So where did everyone get the idea that cooling down is a critical part of working out?

The idea of the cool-down seems to have originated with a popular theory -- now known to be wrong -- that muscles become sore after exercise because they accumulate lactic acid. In fact, lactic acid is a fuel. It’s good to generate lactic acid, it’s a normal part of exercise, and it has nothing to do with muscle soreness. But the lactic acid theory led to the notion that by slowly reducing the intensity of your workout you can give lactic acid a chance to dissipate.

Yet, Dr. Foster said, even though scientists know the lactic acid theory is wrong, it remains entrenched in the public’s mind. “It’s an idea we can’t get rid of,” he said.

In fact, Dr. Tanaka said, one study of cyclists concluded that because lactic acid is good, it is better not to cool down after intense exercise. Lactic acid was turned back into glycogen, a muscle fuel, when cyclists simply stopped. When they cooled down, it was wasted, used up to fuel their muscles.

As far as muscle soreness goes, cooling down doesn’t do anything to alleviate it, Dr. Tanaka said. And there is no physiological reason why it should.

Cooling down feels good, and when I have all the time in the world (which is never), I try to do a few "world-famous" Karen Pot Stirrers" and some hamstring and quad stretches.  I love "Huggers" and "Reachers" like you wouldn't believe. But after reading this article, I'm happy to skip the last few minutes of each P90X video -- especially when there are more pressing matters at hand, like eating or pooing.

Reality Check: Ripped in 90 Days?

Earlier this year, Gina Kolata wrote an article for the New York Times explaining that despite marketing claims, it's "not really possible" for an exercise system to drastically change a person's body in just six to twelve weeks.

“To make a change in how you look, you are talking about a significant period of training,” Dr. Kraemer said. “In our studies it takes six months to a year.” And, he added, that is with regular strength-training workouts, using the appropriate weights and with a carefully designed individualized program. “That is what the reality is,” he said.

And genetic differences among individuals mean some people respond much better to exercise than others, said Dr. Mark Tarnopolsky, an exercise researcher at McMaster University in Hamilton, Ontario. He added that although he does not think the before-and-after photos in ads are doctored, most people will not change so markedly no matter how hard or long they work. “I believe they are taking the top one or two people out of thousands,” Dr. Tarnopolsky said.

People who did change their bodies say six months is a bare minimum to see real change.

But wait: Doesn't P90X get flabby couch potatoes "ripped" in just three months? The P90X guidebook's very first sentence says flat-out that "This program is for you, if you want to get toally ripped and get in the best shape of your life." And we know from user testimonials -- not just those featured in infomercials, but also those posted online by independent P90Xers -- that after 90 days, people have six-packs and bulging biceps, right?

Maybe not.

Fitness blogger (and former P90Xer) Begin to Dig recently posted a very thoughtful critique of P90X, focused in part on the art of "before" and "after" photos, as well as the question of who actually gets "ripped" using P90X:

So knowing that we need to get to a low body fat % to get the "get ripped" look, and knowing how much caloric deficit we need to burn FAT (as opposed to just lose weight), and knowing that there's such variation of caloric deficit with P90X and that at the most it's calculated to drop about a pound a week of fat, AT BEST, what does this tell us about the likelihood of getting ripped on P90X?

If all the fat a person needs to lose is 6-12 pounds to achieve the ripped body fat percentage, then it's possible to get to the Ripped Place in the 90 days. Otherwise, it won't happen.

In the end, both Kolata and Begin to Dig end up at the same place: in order to get "ripped" in 90 days using exercise systems like P90X, you need to enter the program with relatively low body fat. Otherwise, you'll need to seek an alternative program, or plan on completing at least one additional round of P90X.

In fact, the P90X materials hint at the same thing, stating that "P90X is an extreme fitness program designed for individuals in top physical condition and health." The program's guidebook also suggests that P90X is for those who "meet the minimum physical requirements outlined in this guidebook" -- suggesting that anyone who can meet P90X's standards is in "top physical condition and health." Yet the requirements described in the P90X Fit Test aren't exactly difficult to achieve. For example, the Fit Test sets forth these "P90X Minimum" requirements:

• 3 pull-ups for males / 1 pull-up for females. Oddly enough, despite the "P90X Minimum" label, these pull-up standards don't actually appear to be requirements at all. The Fit Test says that "many people won't be able to do any pull-ups when starting P90X. You'll get more out of the program if you can do pull-ups," but according to the guidebook, it's okay if you can't.
• 5 inch vertical leap for males / 3 inch vertical leap for females. Really? If a guy can jump a mere five inches off the ground, he's in "top physical condition"? According to this website, a vertical leap of less than 12 inches for men and 8 inches for women merits a rating of "POOR."
• 15 push-ups for males / 3 push-ups for females (or 15 knee-version push-ups). Again, these requirements are below other published standards.

It's understandable why P90X has set the bar so low; BeachBody wants as many people purchasing and using their products as possible. But after reading post after post on the TeamBeachBody.com message boards from P90Xers who are frustrated with the lack of dramatic change in their bodies, I have to wonder if their expectations were unfairly inflated.

Personally, I'm happy with what I've gotten out of P90X thus far. I started the program with about 11 percent body fat, which means I was in the "sweet spot" for P90X: I didn't have much fat to shed to start seeing some results. The variety in the workouts have kept me engaged and committed to my exercise routine. I'm seeing positive changes in my strength, balance, flexibility and body composition -- and seeing my progress has boosted my motivation to get into even better shape. I'm also certain that anyone who follows the P90X diet and exercise plan for 90 days will see improvement -- how could they not?

But does the hype match reality? Can anyone who diligently follows the P90X plan actually get "totally ripped" in just three months? My conclusion: Probably not. While some P90X users will get "totally ripped," it appears that users who enter into the program with more than 15 or so excess pounds of body fat shouldn't expect to see the same "ripped" results after just three months.

The Myth of the Fat Burning Zone

I'm shocked and dismayed by the fact that even now -- years after the "Fat Burning Zone" myth has been debunked -- cardio equipment manufacturers continue to propagate this garbage.

Just about every treadmill or exercise bike you've ever seen has a chart on it showing users how hard to push themselves to achieve their chosen fitness goals. According to charts like the one pictured below (which are often programmed into the electronic guts of the cardio equipment), you're in the "fat burning zone" if you're exercising at 50 to 60 percent of your maximum heart rate, and you're in the "cardio training zone" if you're at 75 to 85 percent of your maximum heart rate.

This is bullshit.

For weight loss purposes, the theory goes, it's counterproductive to work too hard; instead, you'll optimize your fat loss if you take it easy and work out less intensely. According to this argument, low-intensity aerobic training forces your body to burn more fat as an energy source, while high-intensity cardio work burns more sugar and less fat. As New York Times reporter Gina Kolata summarized in her excellent 2003 book, "Ultimate Fitness: The Quest for Truth about Exercise and Health":

The idea is that if you want to get rid of fat, you should force your body to burn it. Muscles prefer to use sugar, in the form of glycogen, for energy, because it is so easy to metabolize. but they also can use fat. The fat-burning-zone hypothesis says that if you don't push yourself too hard, your muscles will burn fat and you will lose weight. Extreme exertion, however, will force your muscles to burn glycogen, leaving your body's fat intact.

Sound too good to be true? It is.

Here's the real deal: While it's true that a higher proportion of calories burned during low-intensity exercise comes from your flab (approximately 60 percent versus 35 percent from high-intensity workouts), higher intensity exercise still burns more calories from fat overall. Kolata writes:

It turns out that the myth of low-intensity-exercise fat burning is a misunderstanding of a basic relationship, best seen on a graph. One line shows muscles' use of fat as an energy source as a function of exercise intensity, and another line depicts muscles' use of carbohydrates as a function of exercise intensity. the crossover point, where equal amounts of fat and carbohydrate are being burned, comes at about 60 percent of your maximum effort, or a heart rate that is about 70 percent of maximum. After that, the amount of carbohydrate burned exceeds the amount of fat, and this imbalance increases as exercise intensity increases. If you guet to your maximum heart rate, less than ten percent of the calories you burn will come from fat.

That led to the argument that as long as you keep your heart rate low enough, you will burn more fat than carbohydrates and you will lose more weight. The problem is that the argument is neglecting a crucial component: the number of calories burned. The harder you work, the more energy you expend, and the more calories you will need.

In other words, who cares if a greater percentage of your calories are burned from fat than from sugar/carbs? What really matters is the total number of calories you burn from fat. And the more intense the exercise, the more total calories (from both fat and carbs) you'll burn.

So suck it, "Fat Burning Zone" charts.