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Why Doesn't Exercise Lead To Weight Loss?
antdude writes "The New York Times' Well blog reports that 'for some time, researchers have been finding that people who exercise don't necessarily lose weight.' A study published online in September 2009 in The British Journal of Sports Medicine was the latest to report apparently disappointing slimming results. In the study, 58 obese people completed 12 weeks of supervised aerobic training without changing their diets. The group lost an average of a little more than seven pounds, and many lost barely half that. How can that be?"
The Hackers Diet makes it clear: Exercise just doesn't burn that many calories. You can lose weight just by eating less calories than you burn, no exercise required.
http://www.fourmilab.ch/hackdiet/www/hackdiet.html
Putting stuff in your mouth is just step one. How you chew your food, how well it is digested, how active your metabolism is, all these will affect how much energy you actually get out of your food.
Still, physics still stand: Use more energy than you get through food you _will_ lose weight.
.: Max Romantschuk
Well, a 3.5 to 7 pound weight loss over 12 weeks isn't such a bad result. You can't just diet, you have to change lifestyle. TFA seemed kind of whiny, like one expects to magically melt the pounds off if you run around a while. Even moderate physical activity only burns a couple of hundred calories per hour - that's one brownie.
Then there is the issue of converting fat to muscle (which weighs more) and the fact that people in general don't exercise as much as they think they do. For most people, weight control is hard, it's basically a lifetime commitment to minimizing calories and maximizing physical work.
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Your body is not a simple machine. How much you eat impacts how much you use; simply cutting calorie intake will just cause your resting metabolism to drop. Worse, you might start metabolizing muscle.
if you are still munching your way through 6 soft drinks, 2 packets of doritoes, a couple of chocolate bars and fried chicken each day you are still sucking in a hell of a lot more calories than you can burn off with just exercise?
The main role of exercise in weight loss is to help you maintain your metabolic rate ( or increase it a bit) while eating a normal amount of calories.
For a regular guy this should be about 2500 to 3000 Calories depending on your body size.
If you just cut your calories, your body is going to tend to just drop it's metabolic rate, so it's harder to lose weight with diet alone.
Oils and fats have 4 times the energy packed in them as carbs and protein, so if you are eating a lot of fatty food it is going to give you a lot of calories without filling you up much.
a normal healthy diet (ie. balanced protein/carbs and healthy fats, like from nuts, fish & avocados) plus exercise is the way to really succeed. Have a big heap of non-starchy veggies and it will really help fill you up without too much extra calories compared to having say, fries with your steak.
Oh. and diet drinks have been found to have a tendancy to fool your body it is starving, which gives you a bigger appetite, so avoid those & just drink fewer sugary beverages instead.
Losing weight isn't rocket science. Increase /maintain your metabolism a bit with 30 min excercise a day and reduce your calorie intake to below what your body burns is all you need to do - and be patient. Don't expect to lose more than about 2 pounds a week - any more is too fast and unsustainable in the long term.
The muscle you put on with exercise also helps you maintain your weight loss because muscle burns more energy than fat.
Break out of the overweight geek stereotype and be a healthy fit geek - you will think better too when you improve your circulation.
If you just cut your calorie intake, your body will adjust. You have to exercise so you're body doesn't decide that your muscle mass is more expendable than your energy reserves (fat).
It's more than that....after getting through the sensationalistic part, the New York Times article gets to the main point: our bodies are really efficient, and don't burn that many calories. Running for an hour could burn only 200 or so. You can replenish that with a bottle of Gatorade. In fact, most people who exercise eat more to compensate for the calories they've burned, because they are hungry.
Also, in neither of the studies do they actually monitor the food intake. So while it says that the diet didn't change, the subjects very well could have eaten more.
Basically if you want to lose weight, you're going to have to do something with your diet. This is something that was common knowledge 25 years ago, but somehow we seem to have forgotten it.
Qxe4
Like all good science, that's true in an ideal world. In reality, it's a bit more complex. Stop eating so much and your metabolism slows, which means you burn less and need to eat less still. In fact, it's quite possible to starve to death with excess body fat still in place, simply because your metabolism slows too much and available energy stores aren't being depleted.
Weight loss requires the one-two punch of diet and exercise. Dieting reduces intake, and exercise burns energy and, crucially, maintains metabolic rate. Dieting can't do it alone, and nor can exercise, for that matter.
The report tells us nothing new - this has all been known for a long time.
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Even if you're a tub of lard, the body reduce your metabolism and metabolize unused muscle mass before using fat reserves.
McDonald's hasn't been around long enough to have an evolutionary impact. Starvation has.
If you eat a lot of food, or if you eat food with a lot of fat in it, then you gain weight.
I started a low carbohydrate diet last July and I found, to my amazement, that it doesn't work that way. I've been eating more fat than I ever did in my life and for some reason I am losing weight. But I almost completely cut down on carbohydrates eating only those on green vegetables. Although I don't count calories -- I feel that I am eating more calories now, compared to my previous eating habits which, while not excessive, lead to gradual weight gain.
I am not saying the body defies the laws of physics but obviously we are not storing everything we eat.
(The argument about the density of muscles isn't strong either: I had to buy new sets of clothes as well. That means I didn't simply replace "heavier" muscle with "lighter" fat)
Show me a overweight Olympic level marathon runner, and I might believe it.
Me thinks you have cause and effect mixed up here. People are Olympic runners because they have a body that's optimal for it, not vice versa.
In fact, it's quite possible to starve to death with excess body fat still in place, simply because your metabolism slows too much and available energy stores aren't being depleted.
I was always under impression that fat is stored in body primarily to be burned when no food is available, as a survival mechanism; and secondarily, to provide thermal insulation. What you describe is essentially in direct contradiction to that. Can you provide any references to your claim (something explaining how such an arrangement could have evolved would also be interesting)?
It's called "density", you know, dense...
Oh, wait, maybe you're already quite familiar with it...
Its kind of like watching an ice berg melt, it takes a long time for not much to happen, and then all the sudden it accelerates and disappears.
When you have more muscle mass, you also burn more calories at rest, and can reach higher levels of exertion thereby burning more calories per hour. So the whole process starts to accelerate.
Fat is less dense than muscle. You may weigh a bit less but it'll be muscle, not fat so you'll be significantly smaller.
It takes about 12 weeks to see results. Then you just have to keep it up, which is why I chose karate and jujutsu. You get fit and it isn't mind numbingly boring.
Btw, the failure rate for diets is something like 95%[1] which it pretty bloody significant scientifically.
[1]http://news.bbc.co.uk/2/hi/business/2725943.stm
Deleted
I know a lot of people are going to talk about CoE. After all, that's the driving equation here. It is absolutely correct, but can we not glean more insight into the problem?
IWAHTE (I Was A Heat Transfer Engineer), so my guess is that what's going on is that people spend the vast majority of their calories maintaining body temperature. If you eat less, your body's first reaction might well be to reduce skin temperature, maintaining core temperature. This theory links the fact that women eat less then men by 20% with the observation that women are complain about being cold earlier than men. Less calories burnt to keep skin temperature high.
In the case of someone who is overweight, they have an additional layer of blubber (yes, basement /. denizens, you are coated in blubber) that insulates them and maintains their core temperature for free. Maybe there's a hysteresis? First the body weight comes down, then the body learns it can waste excess heat maintaining skin temperature, and then, and only then, the body is free to consume additional calories.
Now, I don't do human anatomy, so a doctor would have to chime in and confirm just how much of the body's caloric consumption is lost to heat, vs. other bodily functions.
A personal example: on an average day, I eat some 3500 calories. But I am athletic, and only weigh 70, so this is a "good" 3500 kCal. What I notice is that my skin temperature is always warm, especially compared to women. In fact, I am very comfortable when the temperature is around 15deg inside. I go outside on a 5deg day in nothing more than a sweater and a top hat. I routinely mock my friends who wear a sweater, coat, and scarf when I'm sitting around in short sleeves. Certainly, my body is horribly inefficient, and if society falls in some sort of catastrophe, I will certainly be one of the first to starve (if my 20/800 eyesight doesn't make me walk off a cliff first). However, in a society that has mass amounts of overconsumption, it seems to fit me just fine.
A second personal example: I dated a German doctor who as a 16-year-old doing a year-abroad in Minnesota, had been anorexic. After she came back, she put on a lot of weight: obviously her body reacting to the extreme abuse she had given it. Now as a 25-year-old, she was in the Bundeswehr (German army), and this girl could RUN. She ran marathons. She ran 2 hours with 25kg of weight attached to her. And yet she was always, always overweight by 8kg or so vs. her pre-American anorexia bout. Not a lot, but she was... pudgy. She'd been to doctors, etc, and could do nothing to get her weight down. I lived with her for a while, I can guarantee she ate nothing but healthy food, and only somewhere around 1600-1800kCal/day. However, she liked her rooms warm.
So I am less physically active, yet consume twice as much. The only thing that can explain this is that physical activity just doesn't use that many calories, not compared to maintaing body temperature. Since I go outside without a coat, I burn more calories than she does to maintain the same core temperature.
My two cents, but I certainly welcome other /.er ideas, though.
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The biggest mistake the majority of people who go on a diet is that they approach it as a way to lose weight.
Actually the only way to do this effectively is to approach it as a change in lifestyle, and accept that this is how you are going to be eating for the rest of your life (if you want to stay in good health that is). The next step is to find a diet that can match this requirement. diets like weight watchers do work, but the most effective diet that I have found is a Low Glycemic Load diet. Stabilizing ones blood sugar automatically creates an environment where the body begins to rid itself of excess weight. I use the word diet in the context of a way to eat, and not as a means to an end. The next step is to learn to eat correctly and stick to
It. It takes about 3 months to learn to eat correctly, and can take about 6 months to become acclimatised to the new lifestyle. On a low GL diet one can lose 1 to 2 pounds a week. This continues until you are within your normal body weight range, and then it stabilizes.
I would really recommend a low GL diet to anyone who is serious about wanting to switch to a healthy and vibrant lifestyle.
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I was once obese, 300 lbs. I lost 100 pounds over an 18 month period by going on a low carb diet, with no significant extra exercise. My thoughts on that are that if your body is capable of going into ketosis (the mode where it gears up for using fat as energy, both from food in the stomach and fat stores throughout the body) then it is effective for weight reduction. Also, eating a low carb diet got very boring for me, and I found myself eating less because of this (was never hungry or starving myself though). This of course is different for everyone.
Next major body change was when I joined the Navy. I went into boot camp weighing 199, I got down 8 weeks later weighing 199 but with vastly less body fat. My physical structure changed significantly. I started off not eating to much, but ending up consuming pretty large amounts of calories (and drinking tons of water, that is very much forced on new recruits to avoid dehydration problems which are very common when you are exercising in one form or another for most of the day.) Most of the people in my division did not lose weight, some gained a few pounds, all were in vastly improved physical condition. Not big body builder type musles, but lean endurance muscles.
The best method of weight control/weight loss I know is to not eat until I feel full. If I am hungry I will eat until the hunger stops, and then wait 15 to 30 minutes. Sometimes I find there is more room, usually I find that I am full. It seems to take food some time to settle in and for my stomach to give the feedback to the brain that it is doing alright. The stomach is actually a pretty small organ and the digestive system seems to operate best when working on small loads. Full loads both have the effect of stretching and enlarging the stomach (thus making it more difficult to feel full) and diverting energy to digestion (alot of energy is consumed for digestion, thats why people go on health fasts, to give the rest of the body a period of time where the body's energy can be continuously applied to other systems for repair and maintenance. Thats the idea anyway) that could be used for other things, like keeping one alert and full of energy and providing for the immune system to do its job.
My $0.02
you forget the fundamental psychological effect.
7 pounds, in 12 weeks - some claim it's not bad, some claim it's weight loss so it's okay and so on.
First off, if you weight 238 pounds, going down to 232 pounds is just a pathetic joke. It took you 3 months to get there. It will take you 5 years to get there at current speed. It would be a reachable goal if it was fun, but...
But the second problem is that it's a dull, boring, miserable exercise. From a slim person's point of view, exercise makes you feel far less miserable than from an obese one's.
The thermal isolation makes you sweat like a pig and overheat in matter of minutes.
If lifting a weight uses 50 joules of energy, a fit person will easily lift it, expending the 50 joules distributed equally throughout the volume of thick muscles. A person with poor muscles will expend the same 50 joules but concentrated in thin, weak muscle that aches, hurts and throbs with exertion, it uses the same insignificant amount of energy but feels vastly worse.
The fat gives you extra weight for exercises like push-ups, sit-ups or pull-ups. Sure you use more energy but don't neglect the psychological effect, how miserable and ashamed you feel without breath after two push-ups.
Then you start feeling hungry, and the body which has a tendency to gain fat, usually gains it because your hunger feels more intense to you than to most slim people who just shrug it off. Take it from an obese person, getting really hungry feels somewhat like drug starvation, you feel ultra-miserable. And still you need to cut on the calories.
Oh, with even little strong will you will go like that for a month easily, suffering and feeling miserable, but telling yourself you're doing it to lose weight to be able to do all the things you can't do because you are obese.
After second month of being miserable like that you start having second thoughts.
After third month, when you went from 240 pounds to 220, you can see it will take you another 3 years of feeling miserable before you get out of this swamp. You say "fuck it", drop the exercise and start eating again.
If you can devise a diet that is low-calorie but filling and tasty, if you can devise exercises that are fun, it could work.
And even worse if eating is your method for stress. It becomes a habit. Something stresses you out and you won't calm down until you fill up your stomach. It's a habit like smoking or drinking. Unfortunately, the fundamental rule of dropping any habit is to drop it entirely. If you're a chain smoker, no one smoke a day, you just have to stop. If you're an alcoholic, you can't drink one and stop, you can't drink alcohol at all. But what about eating? You can't drop eating entirely. It's a horrible habit to drop, really.
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That's your problem right there. Let's see:
Fat is a long term storage form of energy. Everything (proteins, glucose) can be converted to fat, but fat cannot be converted back to glucose (unless you count the lone glycerol molecule that holds the 3 fatty acids together on the triglyceride). It's NOT a reverse reaction. Thus the problems begin. It's easy to make fat, and hard to get rid of it.
So how is exercise supposed to get rid of fat then? Well, fat CAN be converted to acetyl-COA and shoved into the Krebs cycle. Only the Krebs cycle is an AEROBIC process and takes place in the mitochondria, not in the cytoplasm of the cells. Aha! Problem #2. Sedentary people have fewer mitochondria than athletic people. Therefore their ability to "burn" fat as acetyl-CoA is limited. An athlete can burn fat just as efficiently as glucose, the only difference being he'll lose out on the couple ATP from glycolysis.
So you need mitochondria, in quantity, to burn up acetyl-CoA and therefore fat. If you don't get rid of the acetyl-CoA somehow, the whole catabolic process starts backing up. How do you obtain mitochondria? Increased exercise - over a sustained period. 12 weeks is hardly enough to increase the number of mitochondria in your muscle cells, much less expect them to burn through a dozens of kilos of fat. But the title of this article is misleading - according to the study the cited article is based on -
Mean reduction in body weight was -3.3 ±3.63kg (P less than 0.01). However, 26 of the 58 participants failed to attain the predicted weight loss estimated from individuals' exercise-induced energy expenditure. Their mean weight loss was only -0.9 ±1.8kg (P less than 0.01). Despite attaining lower than predicted weight reduction, these individuals experienced significant increases in aerobic capacity (6.3 ±6.0ml.kg-1.min-1; P less than 0.01), decreased systolic (-6.00 ±11.5mmHg; P less than 0.05) and diastolic blood pressure (-3.9 ±5.8mmHg; P less than 0.01), waist circumference (-3.7 ±2.7cm; P less than 0.01) and resting heart rate (-4.8±8.9bpm, p less than 0.001). In addition, these individuals experienced an acute exercise-induced increase in positive mood.
So they ALL lost weight. Only some (probably cheated on their diets/lied about their original diet) lost LESS weight than others. Continuing the exercise for more than 12 weeks would probably have caused further reduction in weight. I don't know HOW the submitter can turn that into "Why Doesn't Exercise Lead To Weight Loss?". Oh yeah, but this is slashdot- news for nerds. This site should be renamed to "Slashdot - news for trolls: engage critical thinking now".
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...if you run the numbers and then understand them you will realize that Adkins is a pretty intense "starvation" diet. It's pretty easy to lose weight on a starvation diet assuming that you can tolerate the "starvation" part.
It takes rather a bit of effort to flee carbohydrates to that degree.
A Pirate and a Puritan look the same on a balance sheet.
Even more people (including researchers) don't seem to think about the energy excreted in the feces (or other ways).
I hardly ever see any mention of it in studies related to weight loss, diet etc.
Go check out how many researchers actually take samples and work out how much a subject is excreting.
Then there's was also a study which showed that mice in a bacteria free environment could eat a lot and not put on weight.
See: http://www.npr.org/templates/story/story.php?storyId=95900616
And another which had the bacteria free mice getting gut bacteria from obese mice and ending up fatter than if they got gut bacteria from skinny mice.
http://www.npr.org/templates/story/story.php?storyId=6654607
Based on these, it should not be a surprise that some people will actually find it hard to lose weight despite eating and exercising the same as skinny people. Of course, your diet also affects your gut bacteria populations. I bet consuming lots of "sugar water" isn't going to help breed gut bacteria that makes it easier for you to be skinny.
That stuffed belly look is the end-game of starvation, don't be fooled. That woman with the obese look isn't obese, her body has started breaking down connective tissues which leads to sagging skin and distended bellies.