The war on fat

[LEdlund]

If I take in all of my excess in protein, then only 50% of it will become fat.

What does the other 50% become?

[slkinsey]

When you suddenly deprive your body of food, our body goes into starvation mode--as in use as little fuel as possible, thanks to our evolutionary instinct to stay alive.  And when a diet fails, as it inevitably will, your body is now inundated with excess calories, but it's still in starvation burn-as-little-as-I-can-get-away-with mode.  And you know where this ends.

It's not entirely clear to me that the whole "starvation mode" thing has ever been scientifically substantiated. It has always struck me as a hypothesis that some diet people came up with to explain why it is hard to lose weight and why rebound weight gain is so common after overly strict dieting.

I beg to differ. Kindly see Keys A, Brozek J. Henschel A, Mickelsen O. Taylor HL. Human starvation. Minneapolis: University of Minnesota Press, 1951.

Or this abstract from an NIH workshop: http://www.healthy.net/asp/templates/artic...article&ID=1675

Interesting. Thanks for the link. I stand somewhat corrected. That said, I have several issues:

1. I would very much like to see something that is less than 50 years old, although I imagine that Keys' findings have been corroborated.

2. I wonder how much of the decrease in basic metabolism after a certain amount of calorie restriction is due to the lower caloric requirement of supporting less body mass after weight loss. The NIH Workshop link seemed to indicate that most of the metabolic change Keys observed was due to a decrease in body mass. Indeed, they say, "...hypocaloric diets will induce a drop in RMR [resting metabolic rate]. This seems to be in proportion to the loss in LBM [lean body mass]." I wonder if there are any studies that show a reduction in RMR following, say, one week of caloric deficit.

3. It is unclear how long it would take the body to rebound back to "normal calorie burning" if/when such a metabolic phenomenon occurs. After 1-2 days of normal caloric intake, why wouldn't the body respond with a switch in basic metabolism back to "normal?" If we are to assume that the metabolic change happens quickly and is caused by the calorie decifit rather than the reduction in body mass, would not a reversal of this effect also take place quickly if there were a change in caloric intake?

4. It is unclear how long the period of calorie restriction and how great the extent of calorie restriction must be for such a thing to happen. People talk like it is something that happens at the drop of the hat.

I think it is important to understand what the Keys study was looking at. They had these (presumably healthy) young men on a 2/3 calorie reduced diet over the course of 24 weeks. That is quite a bit of starvation indeed. I would expect to lose around 37 pounds of fat (and perhaps an additional 17 pounds of muscle) if I were among those test subjects, which is quite a lot of weight in a relatively short period of time. To give you some feeling for the effect of this diet: I am a relatively healthy 200 pound male and as such I burn off around 2400 calories/day with just my metabolism (12 calories/pound/day). A 1/3 reduction in my caloric intake would put me at 1600 calories/day. This is the proper caloric intake for someone who weighs 133 pounds, which is what I would weigh if I continued such a diet until I was no longer losing weight.

All this is to say that it does not seem to be the case that a reasonable program of reduced calorie consumption necessarily induces a "starvation metabolism." While this phenomenon may help to explain rebound weight gain, I think that this offers a more plausible explanation for how this commonly occurs.

Thanks for the info.

[slkinsey]

fat is turned into fat with 95% effeciency.

carbohydrates are turned into fat with 77% efficiency.

proteins are turned into fat with 30-50% efficiency.

So If I take in an excess of calories that means that the source DOES determine how much fat I lay down. If I take in all of my excess in protein, then only 50% of it will become fat.

What does the other 50% become?

Yes... that is exactly my question. What happens to the other 50% of the calories?

Let's look at a hypothetical example:

Let's say we have a person who, through a combination of exercise and basic metabolic activity, burns off 2,000 calories a day. This person never eats anything but protein. Every day this person eats 2,500 calories of protein for an excess of 500 calories per day, which the body will store in some form as we know. My understanding is that excess calories are stored as fat and that the body does not store excess calories in the form of protein. I have never, ever read anything suggesting that extra calories are stored as anything else other than fat, so maybe you could explain how this might happen otherwise. So, what I am saying is that this person would gain a pound of fat -- fat having around 3,500 calories/pound) -- every week until equilibrium is reached between calories consumed/burned.

I welcome any other explanation you could offer as to what would happen with those extra calories. Given your explanation, I can see how in a hypercaloric diet composed of mixed protein, carbohydrates and fat that the fat would most likely be stored as fat, as this would be more efficient. But, in such a case, we come back to the calorie is a calorie issue. If one is eating a 2,500 calorie diet that is 500 calories per day over what is required, I don't see how monkeying with the relative caloric contributions of fat, carbohydrates and protein could possibly change the storage of fat in the body.

Edited June 30, 2003 by slkinsey (log)

[Fat Guy]

By the way, I though WHAT THE DIET INDUSTRY WON'T TELL YOU, the article by Paul Campos in the New Republic earlier this year, was an excellent overview of diet myths.

[Fat Guy]

Yes, but I think those people are saying, "hey, I've got an extra $100, I'll spend it on a stereo."

I think most people actually believe they're spending specific money on specific things. But even reformulated your way, that's still a bit of self-deception that people use to justify financially irresponsible purchases. A dollar is still a dollar, a calorie is still a calorie, and most people still refuse to understand either of those realities.

[slkinsey]

By the way, I though WHAT THE DIET INDUSTRY WON'T TELL YOU, the article by Paul Campos in the New Republic earlier this year, was an excellent overview of diet myths.

This, I thought, was one of the most telling things in the whole article:

Blair's research shows that to move into the fitness category that offers most of the health benefits of being active, people need merely to engage in some combination of daily activities equivalent to going for a brisk half-hour walk. To move into the top fitness category requires a bit more--the daily equivalent of jogging for perhaps 25 minutes or walking briskly for close to an hour. (Our true public health scandal has nothing to do with fat and everything to do with the fact that 80 percent of the population is so inactive that it doesn't even achieve the former modest fitness standard.)

This suggests to me that America suffers more from an epidemic of sitting on our asses than we do an epidemic of unhealthful avoirdupois.

...obesity researcher Paul Ernsberger has done several studies in which rats are placed on very low-calorie diets. Invariably, when the rats are returned to their previous level of caloric intake, they get fat by eating exactly the same number of calories that had merely maintained their weight before they were put on diets

That pretty much answers that question, I'd say.

[JasonCampbell]

Yes, but I think those people are saying, "hey, I've got an extra $100, I'll spend it on a stereo."

I think most people actually believe they're spending specific money on specific things. But even reformulated your way, that's still a bit of self-deception that people use to justify financially irresponsible purchases. A dollar is still a dollar, a calorie is still a calorie, and most people still refuse to understand either of those realities.

A calorie may be a calorie, and a dollar may be a dollar; but both are artificial measures defined by man. Some calorific substances are very bad for you, gasoline is a good example.

[mjc]

fat is turned into fat with 95% effeciency.

carbohydrates are turned into fat with 77% efficiency.

proteins are turned into fat with 30-50% efficiency.

So If I take in an excess of calories that means that the source DOES determine how much fat I lay down. If I take in all of my excess in protein, then only 50% of it will become fat.

What does the other 50% become?

Yes... that is exactly my question. What happens to the other 50% of the calories?

Let's look at a hypothetical example:

Let's say we have a person who, through a combination of exercise and basic metabolic activity, burns off 2,000 calories a day. This person never eats anything but protein. Every day this person eats 2,500 calories of protein for an excess of 500 calories per day, which the body will store in some form as we know. My understanding is that excess calories are stored as fat and that the body does not store excess calories in the form of protein. I have never, ever read anything suggesting that extra calories are stored as anything else other than fat, so maybe you could explain how this might happen otherwise. So, what I am saying is that this person would gain a pound of fat -- fat having around 3,500 calories/pound) -- every week until equilibrium is reached between calories consumed/burned.

I welcome any other explanation you could offer as to what would happen with those extra calories. Given your explanation, I can see how in a hypercaloric diet composed of mixed protein, carbohydrates and fat that the fat would most likely be stored as fat, as this would be more efficient. But, in such a case, we come back to the calorie is a calorie issue. If one is eating a 2,500 calorie diet that is 500 calories per day over what is required, I don't see how monkeying with the relative caloric contributions of fat, carbohydrates and protein could possibly change the storage of fat in the body.

Fat is the main long term storage for of energy in the body. The more readily accessible storage from is glycogen, glycogen is a branched molecule composed of the sugar glucose. Glycogen supplies are imporant in the body, but are small compared to fat.

Proteins are what makes the body work. They are the machinery of the cells, which make up our bodies. So when you take in protein it is most efficient to break it down in to its basic components which are amino acids. The body then uses those amino acids to build its own proteins that it needs.

So sugar, or glucose gives off a certain amount of energy, that we could measure in calories. Protein and fat do the same. Protein is used as a last resort for energy, because it is so important in keeping the body's "mechanical" systems running.

Sugar and protein have a different molecular structure than fat. In order to store excess protein and sugar as fat, you must convert the sugar or protein molecules into fat molecules. This costs energy. The energy requirement needed to change a sugar (carb) into a fat is less than that needed to change a protein into a fat.

So since you need to use energy to make a fat, the process is less effecient. So when it is said that the conversion of protein to fat is 30-50% effecient, that means that in the process of converting the protein to fat, you use up half of the enery you would have yielded, had you directly "burned" the protein. This excess energy is given off in the form of heat. So to answer where does it go?--It goes into the environment.

[slkinsey]

So since you need to use energy to make a fat, the process is less effecient.  So when it is said that the conversion of protein to fat is 30-50% effecient, that means that in the process of converting the protein to fat, you use up half of the enery you would have yielded, had you directly "burned" the protein.  This excess energy is given off in the form of heat.  So to answer where does it go?--It goes into the environment.

Ah! Very interesting. Thank you for making that explanation, as that clears up quite a bit.

Just to be sure that we're on the same page, it would seem that the efficiency of turning these things into fat is only relevant to losing/gaining weight if the person consumes practically no fat. Otherwise, the body will simply store excess calories by converting dietary fat to fat storage, which is extremely efficient -- yes/no? So, basically what this information tells us is that, if you are going to consume excess calories, it is better from a weight maintenance standpoint if you eat zero fat and high protein so you make your body burn the maximum number of calories converting the protein to stored fat.

Wouldn't this tend to suggest that the best diet for fat loss would be a zero fat, high protein, moderate carbohydrate diet?

[Pan]

The fundamental issue of world hunger is massive overpopulation, particularly in "starvation areas" of the world that are not and never will be able to sustain human populations approaching the size they do now.

That's not true. There is plenty of food to go around. The primary problem is terribly inequitable (and also often inefficient and corrupt) distribution of food, money, and resources generally. The rich virtually never starve, no matter how many people are living among them, nor are the places with the highest population density (the Netherlands among them, I believe) consistently the ones with the most starvation, nor the places with the lowest population density (notably including the Sahel and Angola) consistently the ones with the least starvation. It's true that there are some examples of thousands of years of overgrazing destroying the topsoil, e.g. in Ethiopia, but starvation is often caused by war and use of land to grow cash crops for export on large estates rather than subsistence crops on individual, peasant-owned crops - not by "overpopulation."

I am by no means suggesting that the population explosion has no ill effects. It does. But starvation, for the most part, is not one of them, at this stage.

[Fat Guy]

I agree with you, FG, that you fit the mold of a person who knows a great deal more about nutrition than the average person, eat no fast food, yet, as you admit, are obese.  The difference, however, is that food is a way of life for you.  You eat out multiple times a week, cook lavishly at home, etc.

Thinking about this comment from way back a bit more, it occurs to me that it doesn't really explain the situation. If I ate half of what was on my plate, I'd lose weight. I could cook the same things, eat at the same restaurants, etc., and be fit and trim. The problem is simply that I eat more than I should.

[corvus]

Wouldn't this tend to suggest that the best diet for fat loss would be a zero fat, high protein, moderate carbohydrate diet?

There's a limit to how much protein your body can process into glucose in your liver, and it's not enough to sustain you properly. So yeah, I guess you'll lose weight quickly as you experience "rabbit starvation". Then again, you can always up your fat or carb intake to compensate and be just fine.

I know zero fat is impossible, but also note that there are some important fat soluble vitamins (A, D, E and K). Without fat, you wouldn't be able to absorb them. I don't know how much fat you'd need though. I usually eat at least 60% fat myself. I hope that's enough.

And choosing carbs with lower glycemic load ratings[1] will help control your blood sugar and insulin levels. Since one of insulin's many jobs is to store glucose as fat, this may give you another weight loss advantage. Plus, your blood sugar's stability will help you from feeling hungry two hours after eating.

So, for best weight lose, maybe an adequate fat, higher protein, low unrefined carb would be even better. You'll be able to induce a caloric deficit and hopefully not feel hungry all the time.

[1]Glycemic Index On-Line

[mjc]

So since you need to use energy to make a fat, the process is less effecient.  So when it is said that the conversion of protein to fat is 30-50% effecient, that means that in the process of converting the protein to fat, you use up half of the enery you would have yielded, had you directly "burned" the protein.  This excess energy is given off in the form of heat.  So to answer where does it go?--It goes into the environment.

Ah! Very interesting. Thank you for making that explanation, as that clears up quite a bit.

Just to be sure that we're on the same page, it would seem that the efficiency of turning these things into fat is only relevant to losing/gaining weight if the person consumes practically no fat. Otherwise, the body will simply store excess calories by converting dietary fat to fat storage, which is extremely efficient -- yes/no? So, basically what this information tells us is that, if you are going to consume excess calories, it is better from a weight maintenance standpoint if you eat zero fat and high protein so you make your body burn the maximum number of calories converting the protein to stored fat.

Wouldn't this tend to suggest that the best diet for fat loss would be a zero fat, high protein, moderate carbohydrate diet?

I'm not sure we are exactly on the same page, because I don't exactly understand what you mean. As i understand it the efficiency of turning these things into fat is always relevant, no matter if you take fat in or not. The amount of fat the body can store seems to be endless. So if you take in excess fat it will be turned into fat, and if you take in carbs and protein in excess of what your body can store/use in those forms then it should be converted to fat by this ineffecient process.

Something I didn't mention before: As you have said a pound of fat contains 3500 calories. To lose a lb of fat you must have a caloric deficit of 3500 calories. Because of the fact that the storage of fat is inefficient, if you eat a "normal diet", meaning one constisting of a mixtures of fats, proteins, and carbs, you have to take in about 4000 calories to lay down 1 lb of fat.

As to what diet would be best for maintence I think its hard to say, because you can't really look at any single of the bodies metabolic processes in isolation. Also just because you maintain weight, or lose weight, doesn't mean what you are doing is good for your health.

But I agree with you, Based on these numbers it does seem that a no fat, high protein, moderate carbohydrate diet would be the best kind for weight loss/maintenance. The carbohydrates should be the complex type. I can't find any studies that look at this, so I don't know.

Complex carbohydrates are made up of simple glucose molecules that are put together in a branched form. The advantage of complex carbohydrates over simple carbohydrates is that, the simple carbohydrates are broken down into glucose molecules quickly by the body, while the complex ones are broken down slowly. The break down product is glucose. When there is a lot of glucose in the blood the body will use it to make energy, store as glycogen, or store as fat. The problem with simple carbohydrates is that since they are broken down so quickly, the bodies needs for energy and glycogen stores are quickly met and the rest of the glucose is turned into fat. The complex carbohydrates, because of their "complexity" are broken down much more slowly by the body, therefore there is less excess glucose in the blood stream that is turned into fat.

I think the problem with high protein diets is that they are usually based on animal proteins and so are also high in fat. Of course this is exactly what the atkin's diet is and it does appear effective for weight loss, but may be dangerous as people like Dr. Ornish suggest.

Ornish suggests a diet high in complex carbohydrates and vegatble/bean protein. He present data that shows that this diet "reverses heart disease" and help people lose weight. The reason you lose weight on this type of diet, is that you take in many less calories and feel satied faster by the complex carbs than by fats and proteins.

Honestly Its really hard for me to say what is best, I have a good understanding of the basic processes of metabolism, but will gladly admit that at this point in my training I do not fully understand how all of these processes interact.

Edited July 1, 2003 by mjc (log)

[inventolux]

What about a war on low fat?

[corvus]

Ornish suggests a diet high in complex carbohydrates and vegatble/bean protein.  He present data that shows that this diet "reverses heart disease" and help people lose weight.

Ornish's study was flawed. See Ravnskov's The Cholesterol Myths, pp 222-224 for the sordid details.

[dave88]

how can there be tv networks entirely dedicated to food when there are so many starving people?!? its almost comedic to see you people splitting hairs with regard to 'dean ornish's interpretations'. feh...

like drugs, there is an addictive/sensoral quality about food. serotonin and other neurochemicals are involved when people eat.

the way this country (u s a) creates industries relating and capitalising food and contrarily diet, SUCKS.

have fun, suckers.

common sense has been lost due to careful manipulation and tolerance of ideals set by corporate amerika.

julia child and i agree: so many people are afraid of fat because they dont know how to manage it properly. few know how to eat.

[inventolux]

What about a war on low fat?

I think this guy is onto something.

[dave88]

What about a war on low fat?

I think this guy is onto something.

i see where your going.

[macrosan]

I agree with you, FG, that you fit the mold of a person who knows a great deal more about nutrition than the average person, eat no fast food, yet, as you admit, are obese.  The difference, however, is that food is a way of life for you.  You eat out multiple times a week, cook lavishly at home, etc.

Thinking about this comment from way back a bit more, it occurs to me that it doesn't really explain the situation. If I ate half of what was on my plate, I'd lose weight. I could cook the same things, eat at the same restaurants, etc., and be fit and trim. The problem is simply that I eat more than I should.

You eat more than you "need", meaning simply that within the context of your genetic body size and type you ingest more calories (or some such units) than you burn off through metabolism and activity. Assuming that you haven't changed your eating habits, or your activity levels, why hasn't your weight continued to increase ? As far as I can see, the only reason your weight has stabilized is that third factor --- metabolism. It seems to me that as people gain weight, their metabolism compensates by operating internally to increase calorie burn. There comes a point when the process levels out, weight becomes stable, and the body has adjusted to deal with that weight. I would suppose that this is a natural process, and I have always believed that different people are genetically "designed" by nature to adopt different body weights.

Of course there are health problems associated with obesity, but there are also health advantages. And there are health risks associated with thinness. Society is so preoccupied with obesity, that it almost ignores these last two issues. The term obesity has become badly overused and misused by the medical profession, and by the health industry.

I do support the concept of educating people on the health risks of obesity, and of bad diet, and of lack of exercise. I disagree with FatGuy when he says that we don't have sufficient facts to carry out such education. I agree we don't know everything we need about what constitutes a "healthy diet", but we do have some general pointers on issues such as variety of diet, vitamin function, protein biology and so on to give people a general (although inconclusive) education; more important, we do know enough about what gross overweight can do to people's health at least to make people aware of the need for them to think about diet and exercise.

But I also think the net of "obesity" is being flung far too wide. I understand that Arnold Schwarzenegger is classified as obese by current medical standards, and that's just foolish. In my view, a proper definition of obesity has to take into account the genetic predisposition I talked about earlier. Some people are designed by nature to be "fat" and I think we tamper with nature's intent at our own risk. Some of my best friends are "fat" and their whole personality and character is colored by that fact. That's just another example of "nature's rich variety" and we should cherish it.

[mjc]

Of course there are health problems associated with obesity, but there are also health advantages.

What are they?

[Fat Guy]

Of course there are health problems associated with obesity, but there are also health advantages.

What are they?

Fat people are rarely anemic. I've seen some information indicating that they tend to have less cancer overall. They do a lot better in terms of broken bones. They are less likely to be killed by infectious diseases once those diseases are contracted. They are less likely to develop osteoperosis. Suicide rates are lower. Most of these health benefits max out at a certain level of fatness, though. There don't seem to be any health advantages to extreme obesity.

[slkinsey]

Assuming that you haven't changed your eating habits, or your activity levels, why hasn't your weight continued to increase ?  As far as I can see, the only reason your weight has stabilized is that third factor --- metabolism. It seems to me that as people gain weight, their metabolism compensates by operating internally to increase calorie burn. There comes a point when the process levels out, weight becomes stable, and the body has adjusted to deal with that weight. I would suppose that this is a natural process, and I have always believed that different people are genetically "designed" by nature to adopt different body weights.

The first part of this is easy to explain when you understand that each pound of body mass burns off about 12 calories per day. So, for any given caloric intake there is an "equilibrium" weight where the calories consumed will equal the calories burned. I'll make an extremely simple example: Say you have a 200 pound male who burns off 2,400 calories a day (for the sake of simplicity we are going to assume that this person lies in bed all day long and does not burn off any calories from exercise). Further, suppose that this person normally consumes 2,520 calories a day -- 120 more than he burns. As we know, this person will gain weight. But once the person gets up to 210 pounds, he will stop gaining weight because he is consuming the same number of calories he burns. This is because the extra ten pounds of body weight burns 120 calories/day. The reason people tend to stabilise at a certain weight is because they tend to consume/burn right around the same number of calories on a daily basis.

Whether or not people are genetically predisposed to put on "excess" weight... it seems fairly clear that some are. The mechanism by which this happens is not entirely clear, however, to me at least.

[Varmint]

Of course there are health problems associated with obesity, but there are also health advantages.

What are they?

I can only say that I've met a lot more thin neurotics than fat ones!

[slkinsey]

Just to be sure that we're on the same page, it would seem that the efficiency of turning these things into fat is only relevant to losing/gaining weight if the person consumes practically no fat.  Otherwise, the body will simply store excess calories by converting dietary fat to fat storage, which is extremely efficient -- yes/no?

I'm not sure we are exactly on the same page, because I don't exactly understand what you mean. As i understand it the efficiency of turning these things into fat is always relevant, no matter if you take fat in or not. The amount of fat the body can store seems to be endless. So if you take in excess fat it will be turned into fat, and if you take in carbs and protein in excess of what your body can store/use in those forms then it should be converted to fat by this ineffecient process.

OK... let me see if I can explain myself better here...

Let's say that an adult male burns 2,000 calories/day but eats 2,400 calories a day. We both agree that he will gain weight. Now, let us further say that this guy's diet is such that he takes his calories from the following sources: 800 from fat, 800 from carbohydrates and 800 from protein. So, there are two different ways of looking at the "extra" 400 calories... We can think of it as 133 calories each from carbs, fat and protein, in which case the extra calories would be converted into around 297 calories (129 from fat at 95% efficiency, 102 from carbs at 77% efficiency, 66 from protein at 50% efficiency) of stored fat. But, is there reason to suppose that the body would go that route? If there is plentiful dietary fat around (which there almost always is), why wouldn't the body simply do the most efficient thing and convert 400 calories of dietary fat into 380 calories of stored fat?

My reading of what you are saying is that the body has a separate requirement for fat, carbohydrates and protein respectively and that any calories beyond those requirement are converted into fat according to the efficiencies you quantified. Except, obviously we know that this doesn't happen in the case of a hypocaloric diet where the individual eats more than the required amount of protein, for example, so the "extra" protein calories would have to be turned into something else and used, right? That's where I get confused. Given that the body seems to be able to use excess protein (or carbs or whatever) for something other than fat storage, why wouldn't the body choose the most efficient thing in and use dietary fat as the main source of calories for stored fat? Thanks for offering your expertise on these things, by the way. Is this kind of thing part of your profession or field of academics?

Something I didn't mention before:  As you have said a pound of fat contains 3500 calories.  To lose a lb of fat you must have a caloric deficit of 3500 calories.  Because of the fact that the storage of fat is inefficient, if you eat a "normal diet", meaning one constisting of a mixtures of fats, proteins, and carbs, you have to take in about 4000 calories to lay down 1 lb of fat.

So this assumes approximately 87.5% efficiency in converting extra calories from a mixed diet into stored fat. It strikes me, however, that the amount of dietary fat would not have to be all that high for this efficiency to come up a few percentage points. In the real world, of course, there is not much difference between 4000 calories turning into 1 pound of fat and 3500 calories turning into one pound of fat. If one's diet is consistently 250 calories over equilibrium (not a hard thing to do) it will take only two days more to salt away a pound of fat.

[LEdlund]

And choosing carbs with lower glycemic load ratings[1] will help control your blood sugar and insulin levels. Since one of insulin's many jobs is to store glucose as fat, this may give you another weight loss advantage.

The problem with glycemic ratings is that the foods are rated based on the blood sugar and insulin levels when processing that food by itself. My husband was recently diagnosed with Type II Diabetes and, as his nutritionist pointed out, most people rarely eat just one thing at a time. You can't just add up all the glycemic ratings for the componants of your sandwich and count that because that specific combination of foods, and how it changes the blod sugar and insulin levels wasn't tested. You can see how unreliable the glycemic rating is.