Weighing the Evidence on Exercise | Hacker News Reader

Weighing the Evidence on Exercise

nytimes.com

33 pointsrams39 comments

"Take in fewer calories than you burn, put yourself in negative energy balance, lose weight,” says Braun, who has been studying exercise and weight loss for years."

Weight loss is not this simple - this kind of article enrages me. Everyone wants it to be an easy equation. Low carbohydrate/high fat diets are wildly successful despite not having to monitor calories. All calories are not created equal and simply eating less does not lead to long term weight loss, it leads to hunger.

I know many have talked about this idea on HN before, but in case you missed it, an excellent, eye-opening read is Gary Taubes' book, Good Calories Bad Calories - http://www.amazon.com/Good-Calories-Bad-Controversial-Scienc...

Huge +1 for 'Good Calories, Bad Calories'. Read this and you'll change your bad eating habits immediately.

Exercise is very important, but body composition changes come from nutrition.

(After changing how I ate, I lost 70# in 6 months and have kept that same weight for 2 years, more info for the curious: http://emphaticsolutions.com/2009/01/12/clean-eating-how-I-m...)

I lost 70# in 6 months

How young were you when you had seventy pounds that you could afford to lose?

I was 30 years old, 6' 1" and weighed 250#. 6 months later I weighed 180#. After working out more I'm up to 185# with 9.9% body fat, which is a weight I've sustained now for 2 years.

Yes, burning fat really is that simple. A lot of this gets muddied from other factors, such as how various diets affect body composition, water retention, and appetite (supposedly much of the success of low carb diets comes from increased protein intake, which reduces hunger), and weight is hardly the only aspect of health, but the basic energy in minus energy out equation is true for humans.

See http://www.bodyrecomposition.com/fat-loss/is-a-calorie-a-cal...

Yeah, the oversimplification sounds great, except it is a homeostatic mechanism, people extract and expend calories at different rates, and appetite responds differently to different foods. Energy in vs. energy out matters less if certain types of food aren't sating hunger effectively. First you say it "is that simple" then go on to say "except for..." and list exclusions.

Whenever I feel unsympathetic, I imagine trying to "breath less" for several years.

It is only that simple if you assume that all macronutrients are metabolized in exactly the same way which is not the case (example: fat does not stimulate insulin secretion, carbohydrates [for the most part] do, insulin is the primary regulator of fat storage). Treating the human body like a black box like that is vastly oversimplifying the biochemistry of the digestive process to our detriment.

> All calories are not created equal

A calorie is a calorie is a calorie, or it wouldn't be called a calorie. Put less gasoline in your car, you will run out of gas sooner. Eat 0 calories? Better believe you are gonna loose weight. Eat less than you burn? You cannot NOT burn your reserves

> simply eating less does not lead to long term weight loss, it leads to hunger

And what's wrong with hunger? I personally feel if we tolerated a little hunger we'd be better off. So long as it's not the shooting knives of starvation, you can come to grips with it. I know I have.

>A calorie is a calorie is a calorie, or it wouldn't be called a calorie

A calorie in the form of serum glucose stimulates insulin secretion, which shifts the equilibrium of fatty acid transfer across fat cells walls by increasing the flow into the cell and reducing the flow out.

A calorie in the form of serum fatty acids does not stimulate the secretion of insulin.

Therefore, all calories are not the same. QED

So if I had identical twins and I fed twin 1 ONLY 500 calores of carbs per day, and I fed twin 2 ONLY 500 calores of protein per day, they are going to have markedly different outcomes? I highly doubt it.

I think the big difference between getting your calores from carbs vs fat and protein is that it is exceedingly EASY to consume vast quantities of carbs, whereas consuming the same amount of calories in the form of fat and protein would be much more expensive and satiating.

'A calorie' is a 'A calorie'. Don't confuse macronutrients and their functions on the human body with how much heat they give off when burned. Yes, a calorie is a calorie - a joule is a joule and a newton is a newton.

A carbohydrate is NOT a protein and neither of the two are fats. Carbohydrates, proteins and fats are different. They even have, conveniently for discussion, different names! Guess what - they also have different uses and impacts on your body.

Semantics is important when you're discussing chemistry. I wish people would stop making this stupid argument.

This is important. In fact, it might be useful to note this definition explicitly.

A calorie is unit of heat... not a unit of nutrition.

See http://en.wikipedia.org/wiki/Calorie

You can say there are calories in wood, particularly in the context of combustion (though it's more common to talk about that sort of thing in terms or BTUs or joules).

The article explains a basic tenet of metabolism: balancing caloric intake with exercise is the key to weight loss. However, it does not mention much about the health benefits of exercise nor the importance of eating healthy foods, which is unfortunate because one's health is more important than simply losing weight.

I agree. I think many people make the mistake of looking at exercise as simply a means to an end: losing weight. It has so many other benefits like helping to control blood pressure, improved mood, etc. To me these are more important than simply maintaining a pleasing number on a scale.

I'm overweight according to the BMI and other measures, but I strength train and do cardio regularly. My blood pressure, cholesterol, triglycerides, testosterone, etc. are all perfect.

"“In general, exercise by itself is pretty useless for weight loss,” says Eric Ravussin, a professor at the Pennington Biomedical Research Center in Baton Rouge, La., and an expert on weight loss. It’s especially useless because people often end up consuming more calories when they exercise."

Study, have shown that if your energy expenditure and take-in is the same as dieting, exercise can produce the same results.

I have this hypothesis that it is psychologically easier to exercise off weight than to restrict your diet below maintenance.

Reason why: 1. Less willpower for exercise. Once you are on the treadmill it's easy to continue, while for dieting you will need to control yourself for at least 8hrs. So, comparing 15mins of control for getting started to exercise to 8hrs of control to diet, exercise significantly better.

2.Exercise release endorphins, ie you will be happier after exercising. Dieting leaves you irritable and tired.

3. Exercise builds metabolism, so you will burn at rest[not as much as they would have you believe in some books]. Dieting slow metabolism.

4. At moderately high intensity exercise can reduce appetite.

Drawbacks to exercise: 1) Takes alot of time. Walking at 4mph for 60mins only burns 340 calories for a 150pound man[or something like that]. So, in essence 3hrs of exercise by walk a day will burn 2 pounds a week[provided that you follow a maintenance diet]

Re Will power: I've stopped buying crap food (with some rare allowances). If I do not have it in the house, I cannot eat it. The willpower issue comes up once a week while shopping, and I'm not in the mood for junk food while shopping, so it's easier to not buy it than it would be to not eat it were it in the house.

Exercise, though, requires much more deliberate action, and more than once a week. Once I'm out running it's OK, and keeping going is not a problem. It's the initial choice of go running or sit on my ass and drink coffee in the morning. Dicking around seems to have a a magical sway over me. :(

Despite having almost completely slagged off on exercise over the last few months I'm still just below 180lbs (down from 210 last summer), and I'm sure this is because of my diet. I still need to exercise least my body turn to complete goo, but for weight loss I find it much easier to just not have bad food in the house.

You are telling me that you eat 1000 calories less than required and you aren't tempted to break the diet? :)

I can speak for myself. I've lost 15 kg since last summer, not feeling hungry at all, so it's not "1000 calories less than required", at least not what my apetite requires :) In fact, I don't feel like I'm doing a diet, it hasn't been my intention at all. I simply started eating a lot more fruit, in part by accident (didn't know how delicious is pinneaple), in part for convenience (apples are easy to bring in the backpack, salads come now in cheap bags), in part because of my son (he loves orange juice at all times, I eat the ones that remain).

Also it's better to avoid prepared food. I still eat a lot of pasta and meat (I've just enjoyed a 250 g steak) and enough seafood. The only significant casualties are bread (only with meat or fish) and cheese... like Hurley said "everybody likes cheese", but it does no good to me :-(

I agree that exercise is great. But I live far from sea, so I can't windsurf most of the year, and jogging bores me to death. Once year ago I went to the gym and it was really good, but it made me really hungry, so it didn't help with weight lose. In my twenties it was different, but at the time it was much more intense than what I can do now.

A 1000 cal. less .. what, each day?

I have no idea. I used to eat a lot of peanuts. And peanut butter. Possibly the greatest foods ever. And a lot of granola for snacks. And chips.

Then I found out about the caloric cost of these things. Holy shit. (Well, the chips were not a surprise.)

I was quite sad (did I mention I love peanut butter?), but also quite sad that my weight was slowly creeping up, past 200 lbs and then towards 210. And I saw some pictures of me giving a talk on stage, and cringed. (Big win for vanity, boys and girls. )

So I changed what I ate, and started going out running. Over about 4 or 5 months got down to 180 lbs (and greatly increased my endurance and improved my heart rate). Then the weather got too cool for my wussy ass, and I wasn't feeling well, and excuses, excuses.

Now it's been about 3 months since I did any real exercise (aside from occasional walks around the block), yet my weight has stayed at least constant, though it may be dipping lower.

The combination of exercise and diet change did wonders, but I believe that diet change alone would still have brought the weight down, albeit more slowly.

I'm still amazed that when I weigh myself I never go above 180. Lately it's been 178 lbs. But simply eating less is not a good plan for a healthy body, so I still need to get my butt in gear. Maybe just boot up the Wii again ...

What about running in the evening? I find it requires much more will power to work out in the morning because I'm tired, and I have a bunch of things I feel like I should be doing. But after I'm done working for the day, it feels good to do something physical.

I find that if I don't get my ass out the door first thing in the morning, it isn't going to happen. Not that it's impossible, but far less likely.

I also find it very difficult to run in the morning, not necessarily because I feel like I need to get to work but because I just feel very stiff and tired when I get out of bed. Maybe it's come with age, and maybe it wouldn't be such a problem if I was in better shape, but at my current half-ass shape it's quite a hurdle.

"Maybe it's come with age, and maybe it wouldn't be such a problem if I was in better shape, but at my current half-ass shape it's quite a hurdle."

FWIW: My 50+ sorry ass wasn't so keen on exercising either, but I started by just going walking in the morning,and not trying to be too ambitious. Found some good audio books to listen to. After a while I felt good about that, felt my energy improving, and moved to running. At first it was more walking than running, but I would just push myself a bit, making a game of it. Before long the walking/running ration switched.

I'm in pretty good shape, and training in the morning is always more difficult. I train mid-morning on Saturdays, and it always takes longer to get going. I think just the act of being up and moving for even half a day gets you looser and more warmed up than if you stumble out of bed and start doing something.

The few times I've done strength training first thing in the morning have been hard. I remember doing squats at 9 am and just dragging ass the whole time.

There is good evidence that you cannot simply burn off calories this way. That the body will reduce energy consumption at other times to compensate. The overall effect of exercise on energy consumed by the body is minimal. That is, exercise does not build metabolism and in the absence of increased food intake exercise will result in lower metabolism. Try reading Good Calories, Bad Calories. I've been surprised by the number of things I have thought or been taught that are directly contradicted by the experiments reported in this book.

http://www.unm.edu/~lkravitz/Article%20folder/exandwtloss.ht...

"In contrast, Sopko et al. (1985) in a twelve-week study, with obese men, reported that when the negative energy balance created by diet only and exercise only are equal, the two treatments produce similar results. The participants in the diet only group (n=10) experienced a weight loss of 6.1kg by restricting their caloric intake 500 kcal/day. The exercise only group (n=6) lost 6.2 kg by performing a treadmill walking program in which they expended 500 kcal/day. The men in the diet only group went from a body fat of 31.4% to 25%, where as the exercise only group went from 26.7% to 19%"

From reading this, it seem like many studies didn't attempt to make calorie deficit equal.

I think the trouble is what they leave uncontrolled. If type of food is important and you only measure total calories you have a problem in your experiment design. It seems here there is also a subject selection problem. A 5% body fat difference for starting out is pretty significant. This is the trouble with the vast majority of this research. It's done in such a way that it's hard to learn much from it.

My experience is the opposite of your theory. If you have any obligations (working married father of 2 here), it is darned hard to modify my schedule to include significantly more exercise. However my life follows a routine. It wasn't hard for me a few years ago to drop my soda habit, cut out my afternoon snack, and drop my dinner down to a 6" sandwich.

Based on my experience, the problem with your theory is simple. Weight gain and loss is not a matter of will power. If you approach it that way then you need to maintain the thought in front of your head and focus to an extent that we find hard. It is a question of habits. And that makes it a question of what routines are easiest to stick into our lives. For me, dropping unnecessary eating sessions, and reducing what I ate at others, was a lot easier than finding a lot of time for exercise.

(Now in fact I added 15 minutes/day of exercise and kept it up for several years. But while that had lots of benefits, it wasn't why I lost weight.)

Is there good, accessible science (not the opinion of an "expert") about

- What kind of exercise is good for what (e.g. short intense or long light)?

- How quickly does performance increase? What causes better performance?

- Why and how quickly does muscle tissue form?

- Does lung volume increase?

- What happens to your heart?

- What happens to your veins?

- How much exercise?

- How does eating affect exercise? E.g. if you are losing weight, will your body still make roughly as much new muscle tissue?

- Why is it that I get sore more quickly and run more slowly when I haven't eaten enough, even in the first few minutes of running when all the energy is still coming from stuff stored in muscles?

I think the answers to these questions would be very valuable to individuals as well as society as a whole.

It seems like the article is making exercise more mysterious than it is. From what I've read, scientists seem to be more knowledgeable than the state of confusion this article is giving out.

The benefit of exercise in terms of weight loss is that it increases your resting metabolic rate (RMR). So the greatest caloric expenditure is often not during the exercise activity itself. I used to think that it's impossible to burn off the calories eaten from a burger. Now I know better.

Of course, exercise is only effective if your diet complements it. It's not either or, it's both. Both contribute to a net caloric deficit or surplus, creating weight change.

They also don't go into enough detail about the types of exercises. HIIT and weightlifting are particularly effective towards increasing RMR.

I think a great deal of the confusion the article is conveying is not so much about the effect of exercise on metabolism and body composition, but rather its effect on appetite. One of the reasons that we're starting to hear obesity specialists back away from advocating the "moderate-vigorous exercise" as part of a weight-loss plan is because of the things this article brings up: in some people (mostly women), starting an exercise regime spikes appetite and makes it extremely difficult to stick to a calorie-controlled/restricted diet. Thus, even if the RMR increases, it seems the body is insisting calorie intake increase as well -- and I think that's where the confusion they are portraying is mostly stemming from: is it responsible to advocate moderate-vigorous exercise to the obese as part of a weight-loss plan, or is that setting them up to fail? (It seems clear that exercise as part of a weight-maintenance program tends to be beneficial.)

Somewhat orthogonal but apropos:

http://lesswrong.com/lw/am/how_a_pathological_procrastinor_c...

I think after reading all the comments, I still have one more bit to add. The submitted article refers to GENERAL effects of exercise that are observable in current population studies. It does seem to be well established that human beings are adapted to balance their eating with their activity, thus human beings who don't live in conditions of food scarcity may not be likely to lose weight if they increase their level of physical activity.

That said about the general tendency, my observation of the effect of exercise is that it makes me more cheerful, and allows me to substitute the pleasure of fresh air and sunshine and movement for the pleasure of eating. So at least on my part, I have been able to reduce weight (I didn't have a lot to lose at my heaviest) by being more consistent about exercise. These days, there are times when I feel a vague discomfort that I might formerly have treated by eating a snack that I now treat by talking a walk outside. More exercise AND less eating is sure to result in weight loss over time.

"Take in fewer calories than you burn, put yourself in negative energy balance, lose weight"

Join a fitness/nutrition website to provide accountability (and to educate you that the presumably healthy food you're eating is actually highly caloric).

Analyzing my own eating habits, I think that the light, constant exercise factor is representative of regulated behavior that causes people to maintain weight. That is, exercising regularly is a reflection of a person's lifestyle (not a stressed out entrepreneur) that coincides with maintaining a healthy weight, as well as helping a person regulate their behavior (the good feelings and satiation make it easier to not have events where you eat crap).

Exercise a lot. It's easy to reach Marathon levels, and I guarantee you'll loose weight.

I find it interesting how quickly the body appears to decondition when you stop exercising. I suspect the consensus is that this is intended to lower basal metabolism, which would make one better adapted to a food scarce environment. However, if you consume high quantities of food, the body still deconditions. It ignores this data.

So what is the true reason why the body prefers a state of lower conditioning? Even if I lazed around for months in my cave, I'd still want to be at maximum ready for when a neighboring tribe appeared or if I suddenly needed to increase exertion for food.

I find it plausible that exercise has costs that are being overlooked. I'm always impressed by the longevity of academic-types I find in wikipedia, who I presume don't run marathons often. NFL players have extremely low lifespans. Marathon runners tend to have higher rates of heart damage.

As one of the article says "both sides of the argument can bring lots of data to thet table in support of their contentions."

I think scientist should be leading the charge on this. Everybody seem to have their own book or point of view to peddle.

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