Tuesday, October 30, 2007

Does Exercise Make You Lose Weight?

When I was reading Gary Taubes book, Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease, I wasn't all that surprised by his findings about weight loss and exercise.

In fact, much of what he said didn't register on my radar, other than a "yeah that sounds about right" type response as I continued to read on.

My lack of, dare I say, disbelief in his audacity to say exercise doesn't make you lose weight, most likely stemmed from my own experience with weight loss years ago.When I counted calories (a la Weight Watchers) and hit the gym (at first three then five days a week) regularly - including exercise, and then increasing my exercise, it did nothing to make me lose any more weight. Not one who likes to be frustrated, I pretty much quit what wasn't working and quit going to the gym - and then months later, modified my dietary approach to a low carbohydrate diet (a la Atkins). Amazingly, I lost weight and continued to lose steadily without becoming a gym rat again.

So you can see why, as I read Taubes assertions on exercise - specifically that exercise does not make you lose weight or more weight while dieting - it didn't set off any alarm bells in my head. What he was saying meshed with my experience and what I've seen happen with others around me who adopt a carbohydrate restricted diet and don't hit the gym regularly when they start the diet.

Can you or should you exercise?

I'm not convinced Taubes was saying or is saying don't exercise, or that exercise has no benefit - by the end of the book, my impression was that he didn't find any good research to support the idea that exercise will make you lose weight as we're repeatedly told it will as part of the it's all about calories in and calories out; that he found the data doesn't show if you simply eat less and move more and you will lose weight.

Simply put, Taubes contends dieting with exercise doesn't make you lose more weight.

In fact, he reached the contrarian position that exercise does not make you lose weight from a number of studies designed to prove that exercise makes you lose weight - studies that found instead that weight loss is similar between groups who are eating similar calories and one group is exercising and one group is not exercising.

With the release of the book, no one seems to want to actually discuss the studies and data Taubes writes about; instead it seems the intent is to quickly stifle any and all discussion about the matter and maintain the status quo! Heaven forbid anyone learn that they won't lose more weight on the scale if they exercise!

Case in point in the effort to re-direct any discussion on the matter - when Taubes appeared on Larry King Live, among the guests was Jillian Michaels, a former a trainer from the show The Biggest Loser. She was quite visibly upset by the notion that exercise may not help one lose more weight than if they just diet - and stated up front that "exercise is essential to losing weight, just simply because weight is an energy equation."

The following heated exchange then took place:

BEHAR: Gary says exercise makes you hungry and so you eat more.

MICHAELS: Actually, I find that to be untrue in most cases. Exercise releases a series of different hormones, not just insulin.

TAUBES: You ever hear the concept of working up an appetite?

BEHAR: Go, go.

MICHAELS: Gary, if you can show me -- Gary, if you can show me one person you have taken 100 pounds off, then maybe we can apply your theory.

TAUBES: I'm not a diet doctor here. I'm just trying to say ...

MICHAELS: I appreciate that. But here's the thing ...

TAUBES: If you look at the actual evidence when people do clinical trials. Again, she changed a lot of things. She's changed her diet. She changed the way she ate. She exercised. All of those things might have had an effect. But the question is if you're actually doing a clinical trial where you randomize people who exercise versus sedentary lifestyle, you find that you can't show an effect from exercise?

MICHAELS: Wait a second. First of all, exercise actually releases serotonin and endorphins, which have been shown to decrease appetite. They release hormones like your thyroid hormones go up, your estradiol goes up, your testosterone goes up, your HGH goes up.These hormones, not just insuin, are integral to controlling metabolism, body fat and muscle mass. You are a scientist.

You appreciate the fact that science must be applied for a theory to be proven true. Your theory falls short when applied practically because I've applied it.

What's amusing about this particular exchange is how Michaels says Taubes' "theory falls short" when, if she'd actually read the book, she'd know it isn't "Taubes theory" but the conclusion he reached after reviewing the data from a large number of well cited studies.

Note in the exchange - she doesn't wish to discuss the studies; she bases her assertions on her experience with clients who follow her diet and exercise program. From that she believes that without exercise (and without any data to back her up) her clients would not lose the same weight as they do with exercise - afterall, she opened by stating her belief that "exercise is essential to losing weight."

End of discussion. Really! Rather than actually discuss the data or the studies, she instead sums up that Taubes is wrong and says he says what he does because it's "wildly convenient to come up with to sell books."

Okay. Whatever. Who needs data when they have Jillian Michaels?

In a recent New York Magazine article, Taubes wrote (uninterrupted) his analysis of the published data:

This is not to say that there aren’t excellent reasons to be physically active, as these reports invariably point out. We might just enjoy exercise. We may increase our overall fitness; we may live longer, perhaps by reducing our risk of heart disease or diabetes; we’ll probably feel better about ourselves. (Of course, this may be purely a cultural phenomenon. It’s hard to imagine that the French, for instance, would improve their self-esteem by spending more time at the gym.) But there’s no reason to think that we will lose any significant amount of weight, and little reason to think we will prevent ourselves from gaining it.

I point this out because no matter how clear Taubes was in the book, and no matter how many different ways he says it in interviews, somehow something is lost in translation.

Taubes asserts that one will not lose more weight while on a diet if they exercise or that exercise will make you lose weight.

Let's see if I can translate this - two words seem to be lost in the discussions going on about the book - WEIGHT LOSS - with or without exercise is found to be similar when one is dieting to lose weight, even in tightly controlled studies.

Basically, at the end of the day, whether you exercise or don't exercise, the number on the scale is likely to be the same.

For the majority seeing or hearing such words, I think the first thought might just be blasphemy!

And the next might be "burn the heretic!"

That might be because it is so deeply ingrained in our thinking that if you eat less and exercise more you will lose weight. Calories in calories out - if you eat less you consume less calories and if you exercise you burn more calories. Right?

For those of us who have been there, done that and have the XXL t-shirt to prove it didn't work...well we're often confronted by those who insist that it does work if you do it right; with the arguement foisted upon us being that if eating less and exercising more didn't work, then we did something wrong!

Unless of course we want to say we're freaks of nature who defy the laws of thermodynamics!

The funny thing is, Taubes book actually shows how it's possible within the laws of thermodynamics to fully experience little or no weight loss in a calorie deficit with or without exercise.

But, I digress - you'll need to read the book for those details.

Back to the subject at hand - do you lose more weight or not if you exercise?

My friend Adam Campbell, whom I adore, wrote an article on the subject, The Secret To Burning More Fat, on his blog, The Fitness Insider.

Unfortunately, even Adam made a critical mistake in his countering the idea that weight loss isn't all that different in those who exercise compared to those who don't.

He wrote, "There's been some buzz in the news recently about a story that suggests that exercise doesn't help you lose fat. I have plenty of thoughts on the matter, but for now, I'll just provide what I think is a powerful example of why this isn't true." [emphasis mine]

Do you notice the problem right at the start? Fat loss is not the bone of contention - it's weight loss with or without exercise. The issue Taubes talks about, the burning question that it comes down to really is this - at the end of the day, is the number on the scale significantly different in those who exercise when compared to those who don't, when the two groups eat the same calories?

Adam points to a study done by Dr. Jeff Volek as one piece of evidence that one can lose more fat with exercise - not just any exercise, but aerobic exercise and weight training.

But, remember, fat loss is not the bone of contention - it's what is the number on the scale at the end of the day!

After presenting a summary of the study (three groups, same calories; group 1 no exercise, group 2 aerobic exercise, group 3 aerobic exercise + weights) Adam writes, "[e]ach of the groups lost almost the same amount of weight—about 21 pounds...[j]ust because your scale weight may show similar results whether you exercise or not, don't assume that the right kind of exercise isn't providing a signficant benefit."

Exactly what Taubes contends - the weight on the scale is no different in those who exercise compared to those that don't.

Adam rightly shows, quite nicely too, that the quality of the weight lost differs - but the total amount of weight lost, what we're told exercise will do for us if we include it when we diet, isn't different.

Let's remember, Taubes' contention isn't about fat loss versus lean body mass loss - it's about weight loss - and the study presented shows exactly that!

The weight on the scale did not differ in those who did not exercise compared to those who did.

So no one misinterprets my intent here - I do think it's important to include activity and/or exercise in your daily routine; just not as a means to lose weight.

As the study Adam presented shows, a difference can be shown between fat loss (good) and lean body mass loss (bad) in those actively losing weight with diet and exercise (or not exercise).

In the above study those who included aerobic exercise and weight training saw a significant increase in fat loss even though they didn't lose more absolute weight, which means they preserved lean body mass - muscle!

Perhaps a better discussion isn't one seeking to discredit what Taubes wrote, but rather an examination of the studies he included so that we can explain to folks who are trying to lose weight that there are health benefits related to exercise that have nothing to do with the scale number at the end of the day.

Maybe if and when we can end the wishful thinking that exercise makes us lose weight, we can then engage in a discussion about how different types of exercise can help preserve lean body mass and lead to greater loss of fat, even if the total weight loss isn't greater with exercise.

What do you think?

Friday, October 05, 2007

Review: Good Calories, Bad Calories Gary Taubes

In the interest of full disclosure, I'll start by saying I received an advance copy of the book Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease, by Gary Taubes, to review; my acceptance of an advance copy came with no strings; I was neither asked to write a review nor was it implied if I chose to, that it be positive.

That said, it's a good thing I received an advance copy - with over 600-pages of content, notes and bibliography, it's a dense reading adventure!

That's not to say it's difficult to read or understand; quite the contrary, I found it to be well-written and a compelling page-turner. Then again, this is the genre of writing I enjoy most - content that is well researched and strongly supported with references, citations and evidence...so you can imagine my excitment as I opened my copy and dug right in!

I was not disappointed.

I've held my review up until today as I was interested in watching how the media was going to play the release of the book. I wondered, would the various shows and articles encourage their viewers and readers to read the book, or would they seek to discredit Taubes to discourage any real discussion about his positions presented and the research he believes supports them?

Save for a couple of appearances and reviews, the silence around the release of the book is deafening. Taubes appeared on Good Morning America last week. The GMA website provides an excerpt from the book to read online and a video clip from the on-air segment (on same page), along with an area to leave comments. Later (same day) Taubes was featured on Nightline. The Nightline website provides a transcript of the show, a video-clip of the segment and an area for comments too.

This week, the Lifestyle: Health & Fitness section on Reuters published its review titled Count your calories.

In the Reuters article we find a glimpse of what is the at the heart of the book, "Good Calories, Bad Calories" examines an alternative hypothesis to the calorie- and fat-centric idea through decades of literature and clinical data on diet and obesity, Taubes says. It's another way to explain observations about diet and weight gain, he says, one for which strong data existed. "If we had taken this other fork in the road," he asks, "what would we have come to believe?"

The book is, in a word, a masterpiece; not because I think Taubes is right with all his conclusion, but because I feel he took the right approach to evaluate the science - he approached the research from the perspective of a skeptic; that despite his own beliefs at the start, he was going to let the data speak for itself and take him where it led from hundreds of studies published over the last century.

Before I continue with the review of the book, let me say that I believe good science requires one be a true skeptic; a good researcher, a scientist, then is not a proponent of any particular point of view, but remains cognizant of the fact that trials finding support for or refuting a hypothesis are both valuable in our quest for understanding; that seeing and believing the data, both in support of or refutation of a hypothesis, is the primary goal in scientific inquiry.

Simply put, letting the data speak for itself and remaining skeptical that your own belief in a hypothesis may in fact be wrong, is an important part of the process in scientific discovery; if one cannot remain open to the idea a hypothesis may be wrong, one cannot reject hypotheses that fail when put through the rigors of testing.

Which brings me back to the book.

Taubes tackles a number of issues in the book, notably the history of how we got where we are today with public health policies and dietary recommendations, and why, even without good science to support our policies as they developed, they were formed and promoted as fact to the population at large.

He then tackles what was two competing hypotheses at the time we hit the crossroad in our search for understanding how diet plays a role in disease: the diet-heart hypothesis and the carbohydrate hypothesis.

He asked, "If we had taken this other fork in the road, what would we have come to believe?"

The only way to begin to answer that question is to set aside what you think you know, set aside preconceived notions and dig into Taubes book.

It's rich with citations for studies lost in the noise and debate; filled with data and findings that for too long collected dust until he brushed them off for a second look; and leaves the door wide open for us to begin to really examine all the data we have.

The full weight of the evidence, Taubes contends, led him to conclusions he did not anticipate himself at the start; conclusions that are controversial but open-ended for more discussion, interpretation, analysis and trial.

Perhaps you too may find yourself in the same predicament at the end of Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease; until you read it though, you just can't know, can you?

I highly recommend the book, for those who firmly hold carbohydrate restriction is scientifically valid and for those who firmly hold limiting dietary fat is scientifically valid.

At the end of the day our quest isn't to prove what is believed right, it's to discover what is rightly to be believed.

Taubes doesn't just argue that what we're told is wrong, he provokes us to examine our beliefs about a healthy diet by providing a wealth of data from hundreds of studies reviewed in his research in writing the book to argue the validity of the scientific process. That is, he presents a compelling arguement that the supportive data used to maintain the status quo of the diet-heart hypothesis and our current dietary guidelines is not as sturdy as we're led to believe, and makes the case that for well over a century there has been, all along throughout the last century, the competing alternate theory, the carbohydrate hypothesis, that has been ignored despite compelling data.

No matter what one currently believes, this book is an eye-opening examination of the science and the history that led us to where we are today; a compelling review of the weight of the evidence from both sides; and a resource rich with citations that allow us to begin examining and questioning the validity of our beliefs in the connections between diet and health.