So, it seems that there’s a new semi-controversy out there, over research that’s partly funded by Coca-Cola that at least argues that exercise is more important than generally thought in losing weight and maintaining healthy weight. Since this might suggest that the best way to lose might for someone might not be to give up soft drinks but instead to just go for walks every day, and since Coca-Cola is certainly interested in people thinking that, this leads people to be suspicious of at least Coca-Cola’s motives. So Salon has posted an article that was originally at Scientific American with diet and behaviour expert Charlotte Markey talking about it, and at some point talking about the presentation of the group and what it is trying to do. And, after reading it … I simply had to respond. Let’s go through it, shall we?
In your fall Scientific American MIND feature you write “study after study shows that working out is not terribly effective for weight loss on its own.” Why is that?
Exercise increases appetite, and most people just make up for whatever they exercised off. There’s a lot of wonderful reasons to exercise and I always suggest it to people who are trying to lose weight—some sort of exercise regimen keeps them focused on their health and doing what is good for them, and it’s psychologically healthy. But in and of itself it won’t usually help people lose weight.
So … if people exercise, they want to eat more (likely because they are burning more calories). So if they increase their exercise and don’t watch their diet, then they at least don’t lose weight. Well, okay, fair enough. But I don’t think anyone is suggesting — and if you watch the presentation, they clearly aren’t suggesting — that someone who wants to lose weight should just exercise more. What they perhaps should be doing is exercising more instead of trying to lose weight by restricting their caloric intake. In short, if you need to burn 300 more calories a day than you consume in order to lose weight, maybe you shouldn’t look through your diet to find ways to cut those calories, but instead look for ways to exercise more to burn off those calories. The idea is to stop trying to lose weight by dieting, and instead to try to lose weight by exercising more. That no more suggests that you shouldn’t have a balanced diet with a reasonable amount of calories than Markey is suggesting that you shouldn’t exercise at all while dieting.
Two years ago there was a review study in Frontiers in Psychology that concluded dieting often actually led to weight gain. Why would that happen?
When people try to diet, they try to restrict themselves, which often leads to overeating. They cut out food groups which make those food groups more desirable to them. They think too much about short-term goals and don’t think about sustainable changes. But if you are going to lose weight, you have to change your behaviors for the rest of your life or otherwise you gain it back. That’s not a sexy message because it seems daunting.
Or, to put it another way, when people diet, they cut out things that they a) really like and b) that they really need, and so that leads them to cheat in various ways. That’s not a good way to diet. Now, that being said, if you are trying to lose weight, you need to run at a caloric deficit. Running at a caloric deficit is not sustainable. So in general what people need is a short to medium term adjustment for running a caloric deficit until they lose the weight they need to lose, followed by a long term plan to maintain it. The easiest way to do this, it seems to me, is to build a food plan that gives them all of their nutrients and all of the calories that they should need that doesn’t deprive them of the things they really love, coupled with greatly increased exercise to burn off the extra calories. That way, they can eat the foods they want to eat and can get their food choices into a routine, so that when they hit their weight all they need to do is throttle back the exercise a bit into a new routine that maintains the weight they have. The only downside to this is that they might be hungry … but any caloric deficit is going to leave you hungry.
(Note: this isn’t just armchair theorizing. Every time that I’ve lost significant weight, I’ve done it by increasing my exercise. One of my most successful times at losing weight was when on a regular basis I would go for a walk to buy a big bag of Cheetos as my reward. Lately, I’m trying to lose weight again, and managed to lose 10 – 20 pounds over the winter months just by walking a lot more, and that has stalled a bit from my a) not being able to walk as much and b) my “cheating” on the food plan with stuff I shouldn’t be eating at the same time, and mostly that was because I wanted it, not because I was hungry. So I’m definitely partial to the idea that exercise might be the better way to go).
Coke’s message is don’t worry so much about dieting but worry a bit more about exercise. Is there something to that then?
I find everything going on here very troubling. In the promotional video from Coke’s group, linked to by the NYT, exercise scientist Steve Blair says we don’t know what is causing obesity and we need more research. That message is oversimplified and terribly misleading. We actually know a great deal about what leads to obesity. It’s not a great mystery. People are eating too much and not exercising enough…that makes it inevitable that people will be obese. The group’s emphasis on physical activity is misleading based on what the data shows. There’s no data to support saying if you exercise for 30 minutes three times a week that this will take care of the problem. We have data refuting that.
Except — and you can watch the video if you don’t believe me — Blair says that we don’t know what’s causing obesity except that people are, essentially, taking in too many calories more than they burn — or, that they eat too much and don’t exercise enough. In short, he is oversimplifying and misleading by … saying exactly what she says here. He doesn’t say in the presentation that “if you exercise for 30 minutes three times a week that this will take care of the problem”. 30 minutes three times a week is, in fact, a rather low amount of exercise. It seems like a bare minimum. Even if he was pushing that sort of line, it really seems like he’d be pushing for far more exercise than that.
But he doesn’t really say that. He talks about Global Energy Balance, which is pretty much what she talks about herself: the idea that you need to balance the amount of calories you take in with what you burn. His “emphasis on physical activity” is nothing more than a suggestion that, for the most part, the “how much you burn” part has been left out of the discussions. Again, maybe it isn’t really a problem that we eat too much and the wrong things, but that instead we just don’t get enough exercise. If we exercised more, what we’re eating wouldn’t make us gain weight, because we’d burn off the extra calories . In short, that given our activity level we actually need to eat that amount of calories in order to simply maintain our weight. And even then, all he’s really saying here is that we really should think about it and do some science on it to figure this stuff out.
What does a sustainable weight loss regime look like?
It looks like making regular, sustainable dietary changes. It does not have to be a complete revamp of someone’s way of eating since that is not typically sustainable. But, in most cases, it has to involve dropping 300 or more calories per day; that can be done by dropping a couple sodas per day. People have to commit to this and prepare themselves—weight loss is a marathon and not a sprint.
Well, actually … what it means is, in fact, creating a deficit between what you take in and what you burn of 300 calories. So, she has to assume that a) you’re eating at exactly the level you need to sustain your weight and b) that you drink at least a couple sodas per day. Which, of course, didn’t work for me at any rate, as neither were true (I rarely drink soda … or anything other than water or milk). And if someone, say, really likes their 2 pm Coke, then it isn’t sustainable for them either, as they will be doing what she said was an issue in her first comment: depriving themselves.
Alternatively they could walk for pleasure for two hours per day and get burn 340 calories, without feeling like they are depriving themselves of foods they love or completely revamping their way of eating that even she says is unsustainable (I, on the other hand actually did that and it’s mostly working; it’s the exercise and avoiding treats that’s causing issues for me at the moment, not the revamp of my way of eating).
The issue with losing weight through cutting out foods is that you feel deprived. The issue with losing weight through exercising is that you might not have the time to get that exercise in. But it’s generally easier to exercise more than it is to cut out foods that you love.
Exercise is important for sustaining weight loss though, right? Can you talk a bit about what the literature says on that?
Exercise makes people feel good. Avoiding food can just make people feel deprived. Exercise also gets people distracted from wanting food or other stressors, and it alleviates stress.
But exercise also has real physical benefits.
Right. We are burning calories. It’s good for all of our systems—from our heart to our digestive system to our psychological well-being. People should exercise for their health overall but alone it’s not good for weight loss.
So, her big push for exercise continues to be “It makes you feel good”. She almost grudgingly accepts that it burns calories, and even then completely ignores that burning more calories would, in fact, create that deficit that you need for sustainable weight loss. And, as I said above, trying to create that deficit primarily through exercise means that you don’t have to futz around with what you’re eating while trying to lose weight, but can instead eat normally and in a manner that you can sustain long term while shifting your activity levels to lose weight.
Now, I’ve ignored most of the talk about Coca-Cola, mostly because it isn’t important here. But I think that her response shows the precise problem that the Global Energy Balance people are complaining about: the focus is entirely on restricting caloric intake and not on increasing the amount of calories you burn. Heck, we even call it “dieting”. We start from the assumption that we need to eat less in order to lose weight, ignoring the common sense and even scientific view that essentially it’s either. What I think makes sense is that we get our diets right, and then exercise to generate the caloric deficit we need to lose weight. Again, that lets us get into the habit of eating right and not changing that while we try to lose weight, and only shift our activity levels appropriately. We never have to feel deprived because we should have an eating plan that works to avoid that. In theory, this should work, and there’s no reason to think that any of the studies she talks about have actually studied that approach.
So, yeah, we need more data. Whether Coca-Cola funding it is a good thing or not, we need to find a way to do it. How do we do it?