- Cantorsdust
- Aug 10, 2008
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Infinitely many points, but zero length.
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Q
I have a completely serious question: Why does exercise and diet not cause weight loss, in your opinion? After many people losing weight through proper nutrition and burning calories (including myself) I wanted to know why you believe, and how you believe, that the two are not at all linked with weight maintenance. Again, I know this may look like I'm trying to offend someone, and I know saying I'm not trying to is not the same as actually not offending someone but I just want to know the logic.
A
I am not a biologist. I know that biological systems are extremely complex, and that they can and do alter their processes in response to environment. I know that bodies are not closed systems, and a closed system is the only type in which the thermodynamics argument is a valid one – the calories in < calories out theory. I know a lot of pieces. I don’t know, because no one does, the exact mechanisms or reasons (not that biological systems have to have reasons as we understand them).
You were doing pretty well in your phrasing at the beginning, and then you loving lost it.
The “logic” is that it is observably true that there is no real way in which the vast majority of fat people can become and stay thin. None. Zip. Zero.
There are occasional fat people who become thin and stay thin, like child rapist Jared whoever of Subway fame. But mostly what happens is that somebody has some kind of health problem, gains enough weight to be “overweight”, and then addresses the problem in some fashion (possibly diet or exercise, possibly medication or removing an allergen or some other thing), and the weight comes back off. (This actually supports the set-point theory of weight, that there is a weight that each individual body will preferentially return to, and that sometimes that’s fat and that sometimes that’s thin, but for the vast majority of people there’s no way to bring that point down, although you can damage your metabolism by weight cycling and force that point up.) Or else an actual fat person manages to lose a bunch of weight and brags about it while in the honeymoon phase, but two to five years later, all the weight is back and has probably brought along some more.
It’s not a matter of what we believe. It’s a matter of observable loving reality. If you were actually fat, long-term fat not temporarily fat, and lost more than 10% of your body weight and kept it off for more than five years, then you are an extreme outlier statistically. If you fall into one of the other categories – temporarily fat, had a health problem that caused weight gain and corrected it, weren’t actually fat to begin with and just lost the 5-10% or so that it actually is possible for most people to keep off long-term, or you’re still in the honeymoon period and will regain all of it – then you fit the model we’re talking about. But the actual, factual scientific evidence – the evidence we keep on posting and people like you keep on ignoring – says that long-term major weight loss doesn’t work. That aside from extreme outliers, fat people don’t get thin and stay that way. We don’t believe it or logic it, it’s simply fact.
Seriously, go read the links in our FAQ, or the blog @bigfatscience
One more thing. You knew perfectly well that your question was insulting, that it would upset us. I can tell you did because you kept making excuses for it. The thing is, intention isn’t magic, and if it’s rude for a troll, it’s rude for you, too.
Here’s why it’s rude. You’ve clearly seen us respond to people who ask us these questions, so you must have seen us say things like, “Seriously, go read the links in our FAQ, or the blog @bigfatscience.” And apparently you couldn’t be bothered to actually loving do that. Nooooo, you had to demand our time and attention, as if our time is worth less than the time it would take you to go read the poo poo we always loving link to.
Seriously, if you wanted to understand, say, geometry, would you take a class or open a book, or would you write to a professor and demand that she take time out of her day to explain all of it to you right then, even though she already wrote the goddamn book for the class you aren’t taking because you think harassing her instead is a great idea. While telling her she’s wrong about it, based on your extremely limited anecdotal experience of Cartesian planes. And asking for her logic in insisting that two of the angles of an isoscolese triangle are always congruent, because you’ve seen a lot of isosceles triangles where they aren’t!
Seriously, this is how ignorant, foolish and rude you look. You have no idea.
gently caress off.
1. You're definitely not a biologist. Calorie-wise, a body is a closed-system. The only things we take in are air, water, and food, and only one of those has calories. But the body isn't a black box where no one understands the processes. It's actually quite simple. There are 4 primary sources of calories in our diet. Carbohydrates, fats, proteins, and less-frequently alcohol. I will address how each are turned into fat one by one.
Carbohydrates: Starches and complex sugars are broken down by various enzymes, first amylase and then many others on the intestinal brush border, into simple 5-6 carbon sugars. These sugars are then processed by a very, very well understood pathway to generate energy. This pathway includes glycolysis followed by the Kreb cycle. If the body has all the energy it needs, sugars can be shunted. This usually happens after they have been broken down into 2 carbon chains. Fatty acids are created by connecting several 2 carbon chains together. 3 fatty acids are then attached to a 3 carbon chain (also produced from glycolysis) to create fats.
Fat: Broken down into glycerol + fatty acids by lipase in the small intestine. Fatty acids are then transported by chylomicrons to the liver, where they are reassembled into fats and cholesterol repackaged into VLDL (very low density lipoprotein) and sent off into the bloodstream. Tissues then take fats stored in the VLDL, turning into the dreaded LDL that is your "bad" cholesterol.
Protein: Does not directly form fat. Is broken down into its component amino acids and absorbed. Amino acids then reassembled into own proteins. Excess amino acids can be shunted off into other pathways to make glucose and ultimately fat, but this is a slower process, which is part of the reason protein gives you longer lasting energy.
Alcohol: Already enters your body as a 2 carbon chain. Can be converted directly to fat from there via alcohol and then aldehyde dehydrogenase.
All of these pathways above have been very well-characterized. In short, it is well-understood how what you eat is turned into fat on your body. Ultimately every macronutrient you take in is either getting burned and breathed out as CO2, used to make protein, or turned to fat. Those are your 3 options. There are no others.
Now that being said, the regulatory pathways for what goes where are admittedly complex and not completely understood, although great progress has been made in recent years with the discovery of the GLP-1 and leptin/ghrelin axes. But the actual physics and chemistry of the process are not at all mysterious, which is what it appears you're trying to claim here. Dieting, if done correctly, works 100% of the time for losing weight.
2. I have no idea what false dichotomy you're trying to draw between "temporarily fat" and "permanently fat" people. I assume your underlying argument is something about genetics creating people who cannot help but be fat. Again, see point #1. There are no permanently fat people, just temporarily fat people who are successful or unsuccessful with dieting.
3. I think one good proof of long term weight loss is weight loss surgery, which is supremely effective at getting people to lose weight and keep weight off. It can take a morbidly obese person and put them down to the overweight category and keep them there for years. There are definitely failures in the process, and it's not great at getting people to a normal BMI all by itself, but it works quite well. It has been well-studied and found that its primary effect is calorie restriction with some surgeries which take out part of the small intestine also contributing by calorie malabsorption. I think every weight loss surgery success story is proof of point #1, again.
4. I just read your bigfatscience blog FAQ here.. It contains no scientific information. I then went to read some articles on the blog. Let's start with this one:
Dieting causes unhealthy stress. (their title).
quote:
bigfatscience:
In this well-designed experiment, 99 women followed one of four diets for three weeks that were designed to be similar to the kinds of diets people follow in everyday life:
Monitoring and restricting group: Women in this condition were trained to follow a low-calorie diet (1200 calories/day) and complete a daily food diary to monitor their caloric intake.
Monitoring only group: Women in this condition were not placed on a low-calorie diet, but were instructed to complete a food diary to monitor their caloric intake.
Restricting only group: At the beginning of the study, women in this group were given all the food they were allowed to eat during the study. Their diet was restricted to 1200 calories/day.
Control group: Women in this group were not given any instruction regarding monitoring or restricting their diet.
Results:
Monitoring caloric intake caused psychological stress.
Following a low-calorie diet caused physiological stress, as indicated by heightened levels of the stress hormone cortisol.
According to the researchers: “Chronic stress, in addition to promoting weight gain, has been linked with a host of negative health outcomes, such as atherosclerosis, coronary heart disease, hypertension, diabetes, cancer, and impaired immune functioning. To the extent that dieting might potentially add to this stress burden, its psychological and biological consequences would best not be ignored.” (p.363)
Reference: Tomiyama, A. J., Mann, T., Vinas, D., Hunger, J. M., DeJager, J., & Taylor, S. E. (2010). Low calorie dieting increases cortisol. Psychosomatic Medicine, 72(4), 357-364. doi:10.1097/PSY.0b013e3181d9523c
- Mod A
The link to the full text of the study in question.
For starters, it was published in Psychosomatic Medicine. I have never heard of that journal before. It is a minor journal, at best, and certainly not JAMA, NEJM, Lancet, Nature, etc levels of good. It's not even a Journal of Neuroendocrinology level of good. This is at best a third tier journal study. Not a good start. Let's see what it says:
quote:
Abstract
Objective
Prior research has demonstrated that dieting, or the restriction of caloric intake, does not lead to long-term weight loss. This study tested the hypothesis that dieting is ineffective because it increases chronic psychological stress and cortisol production – two factors that are known to cause weight gain. Further, this study examined the respective roles of the two main behaviors that comprise dieting – monitoring one’s caloric intake and restricting one’s caloric intake – on psychological and biological stress indicators.
Methods
In a 2 (monitoring vs. not) × 2 (restricting vs. not) fully crossed, controlled experiment, 121 female participants were randomly assigned to one of four dietary interventions for three weeks. The monitoring + restricting condition tracked their caloric intake and restricted their caloric intake (1200 kcal/day); the monitoring only condition tracked their caloric intake but ate normally; the restricting only condition was provided 1200 kcal/day of food but did not track their calories, and the control group ate normally and did not track their intake. Before and after the interventions, participants completed measures of perceived stress and two days of diurnal saliva sampling to test for cortisol.
Results
Restricting calories increased the total output of cortisol, and monitoring calories increased perceived stress.
Conclusions
Dieting may be deleterious to psychological well-being and biological functioning, and changes in clinical recommendations may be in order.
I just posted the abstract to spare those following along. If you want to go in depth like I did, check the link for the full text.
Initial misgivings:
1. The study is using a secondary endpoint to make a primary argument not supported by their evidence. This study showed 2 things: restricting calories increased cortisol levels, and monitoring calorie intake was perceived as stressful. It did not go on to show anything about outcomes related to those two measures like success of weight loss, amount of weight loss, etc.
2. Restricting calories should physiologically increase cortisol levels. You can ask any doctor or medical student that. Among its many effects, cortisol functions to prevent hypoglycemia by activating gluconeogenesis in the liver. If I restrict calories by not eating during the day, my cortisol will increase. That is not in any way new information. That is demonstration of a known biological effect.
3. Most interestingly, monitoring calories by itself did not increase cortisol. That is, they failed to show the one thing they were trying to show--that dieting causes physiological stress! That also supports that the cortisol increase from restriction is a physiological and not psychological effect.
In short, this study is from a poor journal, fails to show what it set out to do, and may actually show the opposite. Great science there.
Let's take another one.
There is little scientific support for the notion that diets lead to lasting weight loss.
quote:
bigfatscience:
A recent meta-analysis (a study that examines the results of many other studies) of over 50 years of weight-loss research revealed that people can initially lose about 5% to 10% of their weight on virtually any diet program.
This means that a 250 lb. woman can typically lose between 12 and 25 lbs. by dieting. This loss is often presented as “success” by diet companies, even though such a woman would still be categorized as “obese” according to the Body Mass Index (BMI).
But… “These losses are not maintained. As noted in one review, “It is only the rate of weight regain, not the fact of weight regain, that appears open to debate” (Garner & Wooley, 1991, p. 740). The more time that elapses between the end of a diet and the follow-up, the more weight is regained…”
“Among patients who were followed for under two years, 23% gained back more weight than they had lost. Among patients who were followed for two or more years, 83% gained back more weight than they lost (Swanson & Dinello, 1970). Even in the studies with the longest follow-up times (of four or five years postdiet), the weight regain trajectories did not typically appear to level off (e.g., Hensrud, Weinsier, Darnell, & Hunter, 1994; Kramer, Jeffery, Forster, & Snell, 1989), suggesting that if participants were followed for even longer, their weight would continue to increase…”
“The amount of weight loss maintained [after 5 years] in the diet conditions of these studies averaged 1.1 kg (2.4 lb).”
Reference: Mann, T., Tomiyama, A.J., Westling, E., Lew, A.M., Samuels, B., Chatman, J. (2007). Medicare’s search for effective obesity treatments: diets are not the answer. American Psychology, 62, 220-233.
- Mod D
I won't belabor this one, as it's been discussed in the thread. Diets lead to temporary weight loss, and when the diet is stopped and old habits resume, the weight returns. What I think is funny is that even this study posted to the blog supports the notion that people can, in fact, lose weight. The post even admits that a 250 lb woman can typically lose 12-25 lbs by dieting. 25 lbs is good, actually! 10% weight loss has been shown to cause metabolic changes such as a decrease in insulin resistance. 10% weight loss is, in fact, clinically significant weight loss, and I would congratulate my patients if they achieved this.
One more:
A person’s weight is determined by how much they eat and exercise… or is it?
quote:
bigfatscience:
Most people believe that a person’s body weight is a direct reflection of their eating and exercise habits. If Sue weighs more than Etsuko, then it must be the case that Sue eats more and is less active than Etsuko. If Sue just ate “normally” and got “enough” exercise, then she too would be thin!
But this behavioral formula for weight loss can only work if body weight is a predominantly controllable characteristic. It is not.
Large-scale studies of families, including twins who have been reared apart, reveal that fully 70% of individual variance in body weight can be explained by genetics, a degree of heritability commensurate with traits like height. This means that most of the population’s variance in body weight is determined by individual differences in genetic heritage, not individual differences in behavior.
Furthermore, although environmental factors like greater availability of calorie-dense foods, increasing portion sizes, and less active work-lives may explain recent weight gains across the entire American population, these same large-scale studies of families reveal that some people are genetically more susceptible to such (generally uncontrollable by the individual) environmental factors. Thus, many experts conclude that weight is a largely genetic trait that is highly responsive to the environment.
Once genes and the environment interact to settle a person at a given body weight, automatic, homeostatic biological processes work to maintain it as a minimum body weight – or more specifically, a minimum fat volume – within a relatively narrow range. Decreases in energy intake, such as those proscribed by weight loss plans, prompt a cascade of biological changes that resist weight loss. These include shifts in appetite-regulatory hormones that increase subjective appetite and changes in metabolism that reduce energy expenditure, which can persist up to a year after weight loss occurs.
Pitted against these genetic, environmental, biological, and psychosocial factors, is it any wonder that long-term weight-loss is physiologically stressful, and virtually unattainable for the vast majority of fat people?
References:
Friedman, J.M. (2004). Modern science versus the stigma of obesity. Nature Medicine, 10, 563-569.
Keesey, R. E., & Powley, T. L. (2008). Body energy homeostasis. Appetite, 51, 442-445.
Stunkard, A. J., Harris, J. R., Pedersen, N. L., & McClearn, G. E. (1990). The body-mass index of twins who have been reared apart. New England Journal of Medicine, 322, 1483-1487.
Sumithran, P., Prendergast, L. A., Delbridge, E., Purcell, K., Shulkes, A., Kriketos, A. et al. (2011). Long-term persistence of hormonal adaptations to weight loss. New England Journal of Medicine, 365, 1597-1604.
- Mod D
This argument commits the cardinal sin of using population-level statistics such as variance in body weight on the individual level. That's a big statistical no-no. I don't doubt that BMI has high heritability. One's appetite and metabolism are definitely heavily influenced by genetics. But that makes weight loss difficult, not impossible. Again, see point #1. And it is definitely true that there are hormonal changes and neurological changes that accompany obesity. I do want to point out paragraph 4 specifically, though. "Furthermore, although environmental factors like greater availability of calorie-dense foods, increasing portion sizes, and less active work-lives may explain recent weight gains across the entire American population, these same large-scale studies of families reveal that some people are genetically more susceptible to such (generally uncontrollable by the individual) environmental factors." I would argue that eating calorie-dense foods, portion sizes, and amount of exercise are very much controllable by the individual.
In conclusion, I don't fully disagree with your premise. Weight loss is difficult, though physically very possible. That doesn't mean that we should give up and allow overweight and obesity to become normalized in the general population. They are significant health problems with great personal and societal cost. I think instead what this means is that we should have a renewed focus on helping these people maintain healthier lifestyles in the long term, allowing for sustained weight loss. That means specialized clinics, dietician support, continued research into possible pharmaceutical help, financial support for healthier food choices, and a broader cultural shift towards healthy eating and exercise.
Cantorsdust fucked around with this message at 20:23 on Nov 23, 2015
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Nov 23, 2015 20:19
