Fat, Carbohydrates & Science - The Straight Dope

[IzzyR]

What if It’s All Been a Big Fat Lie?

If the members of the American medical establishment were to have a collective find-yourself-standing-naked-in-Times-Square-type nightmare, this might be it. They spend 30 years ridiculing Robert Atkins, author of the phenomenally-best-selling ‘‘Dr. Atkins’ Diet Revolution’’ and ‘‘Dr. Atkins’ New Diet Revolution,’’ accusing the Manhattan doctor of quackery and fraud, only to discover that the unrepentant Atkins was right all along. Or maybe it’s this: they find that their very own dietary recommendations – eat less fat and more carbohydrates – are the cause of the rampaging epidemic of obesity in America. Or, just possibly this: they find out both of the above are true.

It was Ancel Keys, paradoxically, who introduced the low-fat-is-good-health dogma in the 50’s with his theory that dietary fat raises cholesterol levels and gives you heart disease. Over the next two decades, however, the scientific evidence supporting this theory remained stubbornly ambiguous. The case was eventually settled not by new science but by politics. It began in January 1977, when a Senate committee led by George McGovern published its ‘‘Dietary Goals for the United States,’’ advising that Americans significantly curb their fat intake to abate an epidemic of ‘‘killer diseases’’ supposedly sweeping the country. It peaked in late 1984, when the National Institutes of Health officially recommended that all Americans over the age of 2 eat less fat. By that time, fat had become ‘‘this greasy killer’’ in the memorable words of the Center for Science in the Public Interest, and the model American breakfast of eggs and bacon was well on its way to becoming a bowl of Special K with low-fat milk, a glass of orange juice and toast, hold the butter – a dubious feast of refined carbohydrates.
In the intervening years, the N.I.H. spent several hundred million dollars trying to demonstrate a connection between eating fat and getting heart disease and, despite what we might think, it failed. Five major studies revealed no such link. A sixth, however, costing well over $100 million alone, concluded that reducing cholesterol by drug therapy could prevent heart disease. The N.I.H. administrators then made a leap of faith. Basil Rifkind, who oversaw the relevant trials for the N.I.H., described their logic this way: they had failed to demonstrate at great expense that eating less fat had any health benefits. But if a cholesterol-lowering drug could prevent heart attacks, then a low-fat, cholesterol-lowering diet should do the same. ‘‘It’s an imperfect world,’’ Rifkind told me. ‘‘The data that would be definitive is ungettable, so you do your best with what is available.’’

The bottom line is that for the better part of 30 years Atkins insisted his diet worked and was safe, Americans apparently tried it by the tens of millions, while nutritionists, physicians, public- health authorities and anyone concerned with heart disease insisted it could kill them, and expressed little or no desire to find out who was right. During that period, only two groups of U.S. researchers tested the diet, or at least published their results.

Should these clinical trials also find for Atkins and his high-fat, low-carbohydrate diet, then the public-health authorities may indeed have a problem on their hands. Once they took their leap of faith and settled on the low-fat dietary dogma 25 years ago, they left little room for contradictory evidence or a change of opinion, should such a change be necessary to keep up with the science. In this light Sam Klein’s experience is noteworthy. Klein is president-elect of the North American Association for the Study of Obesity, which suggests that he is a highly respected member of his community. And yet, he described his recent experience discussing the Atkins diet at medical conferences as a learning experience. ‘‘I have been impressed,’’ he said, ''with the anger of academicians in the audience. Their response is ‘How dare you even present data on the Atkins diet!’ ‘’

Two issues, as I see it:

1. Who is right about the issue at hand? IOW, is this a one sided article by a NYT writer who is skewing the situation based on bias or ignorance, or is his portrait an accurate reflection of the historical and current scientific positions?

2. If he is right, what does this say about the amount of faith we should in current scientific consensus about anything? There are probably few scientific subjects that are of as great immediate concern as national health policy, and if a possibly erroneous theory can become entrenched and established dogma in this field based on such a small body of evidence, how much more skeptical must we be of established dogma in fields that are more esoteric. (OTOH, once politicians get involved in a scientific matter, all bets are off).

[IzzyR]

The link does not appear to be working - for some reason it is putting the url of the SDMB in front of NYT one. If you delete the front end you will get the correct link and the article - sorry.

[Brutus]

1. The ‘Atkins Diet’ does work, if properly done. I can attest to that. Also, it is a wonderfull diet for weight-lifters, who knew about it long before Atkins

I have heard some say that the diet works because of lower overall caloric intake. I have heard some say it works because the body does not readily store protien as fat. I dunno.

I also don’t know the long-term effects. I drink lots of water; many people on this diet do not, and I have heard that high-protien diets are harsh on your kidneys.

‘Scientific’ studies are a dime a dozen on this topic. I would be more inclined to trust something that JAMA put out, then what is in the latest ‘Muscle Mag’, but JAMA is not infallible…

2. As scientific means become more advanced, outcomes may change. Diet is a tricky thing for science, it appears. Some 122 Albanian woman eats typically fat-soaked Balkan fare, smokes, etc. My fairly health-concious cousin died of heart disease at 45. Who knows? Science doesn’t appear to

[Stoid]

Friend of mine PDF’d this for me after I sent her the link.

1. If anything, this is the beginning of balance. The truth of the situation is walking around us every day, both in the obese low-fat/high carb eaters, and the in the formerly obese high fat/protein low carb eaters.

2. Well, when medicine works, why question? But when it doesn’t… question.

[elucidator]

Anecdotal testimony here. My son was very overweight, and of an age when Pappa Darwin says shit starts to happen. He determined to follow the high-protein low carb thing. I said ok, despite reservations, “balanced diet” and all that.

Huge hit to the grocery bill, felt like Daisy Mae feeding Lil’ Abner nothing but pork chops.

Kid lost, at last count, 80 lbs! He’s still friggin’ huge, but he’s starting to catch those sidelong glances from admiring eyes… You know, the kind that make a young man’s life worth living. That is, if I remember correctly.

Seems to have had a very positive effect, attitude wise. And thats as much as I know.

But I would be very interested to hear from anyone with anthro-paleological experience, rather along the lines of Guns, germs and steel.

Did we start eating heavy carbs because we could? Is that the only real reason? After all, what do Eskimo eat but seal blubber?

[ultrafilter]

It’s very difficult to measure the effects of a specific diet, given the complexity of the human organism, and the incredible variations among people’s reactions to a diet, both across a population and across an individual’s lifespan. Nutrition, as important as it is, is still a fledgling science, and the truth is probably somewhere between the extremes.

That said, I read the article, and I thought it seemed fairly objective. There are a few points I’d like to make:[ol][li] The evolutionary explanation for the low-carb diet does seem reasonable, but that doesn’t mean that any specific low-carb diet is actually good. After all, we can improve upon our situation in the wild in so many ways.[/li][li] Carbohydrates are the main source of fuel used in exercise. While bodybuilders do tend to eat fewer carbohydrates than the general population, most of the ones I’ve encountered still shoot for about 40% of their caloric intake being from carbohydrates (no cite, just my experience). However, they do aim more for complex carbohydrates. Athletes whose primary focus is in endurance are encouraged to get about 60% of their calories from carbohydrates (this is from a book I have on nutrition for endurance athletes).[/li][li] There’s some evidence that a diet high in fruits, vegetables, and fiber will reduce the risk of certain cancers and other diseases. You don’t get fruits and vegetables on the Atkins diet, a fact that the author of the article in question pointed out.[/li][li] Additionally, the nutritional benefits of phytochemicals (chemicals found in plants that give them their taste, color, etc.) are not well understood, but they probably are important–after all, we are omnivores; we evolved to eat plants as well as meat. There is some evidence that phytochemicals need to be eaten in the ratios that they are found in the original plants.[/li] Fat is a necessary food–the health benefits of nuts and fish are pretty well-documented.[/ol]Those are all generalities, though. At bottom, there is a lot of individual variation in humans with respect to nutrition. You really have to find what works for you, and stick with it.

[elucidator]

Excellent advice! Everybody get that?

[divemaster]

Overweight tendencies run in my family. My father died 2 years ago (at 57) basically by eating himself to death. My mom is roundish.

Well, I love food, but have taken care of myself pretty well. I run 4 miles 4-5 times a week, but in recent years, my (already slow) metabolism slowed down even more and I noticed the weight creeping up on me.

The first thing I tried was cutting back on the fat. For snacks, went with baked chips, pretzels, and baby carrots instead of fried foods. Low fat yogurt rather than ice cream. Snackwells cookies. Low-fat salad dressings, etc. I’m not saying that’s all I ate, just that I replaced certain things with lower fat eqivalents.

But you know? I didn’t lose any weight. That was disappointing; not to mention having to eat substandard fare, taste-wise. Then I realized most low fat foods just pack in extra sugar to improve the taste form the missing fat. Of course, extra sugar adds calories and gets stored in your body as fat anyway.

My sister gave me a copy of The Carbohydrate Addict’s Diet which is similar in principal to Atkins but is NOT Atkins. I took the quiz (to see if my tendencies with food, cravings, and weight fit the bill for this diet) and figured this was just what I was looking for.

In a nutshell, no carbs during the day. Then eat anything you want for dinner (as long as you eat within one hour). No late night snacking. This regulates your body’s release of insulin and controls cravings and reduces fat storage.

Now, no carbs during the day means no breads, grains, sugar, or fruit. Certain veggies are right out (corn, taters, lima beans, etc.). I eat a lot of salads (regular dressing); but I also eat a lot of cheese and meats. Breakfast may be a mushroom and cheese omelete with a side of bacon (I eat LOTS of omelets). And bacon tastes good. Pork chops taste good. Lunch might be cream cheese (regular, not low-fat which has extra sugar) and celery or a salad with Ranch or Blue cheese dressing. Carbs are A-OK for dinner, so I’m sure to satisfy my needs there.

I don’t bother to count calories, and I’m sure I get a lot. But I don’t care. I don’t crave carbs like I used to, I have more energy throughout the day, and I eat foods that I like.

I’ve lost 26 pounds in 13 months and am generally satisfied where I’m at. I do not consider this a “diet,” to be abandoned once I reach a certain goal. If I did that, it wouldn’t be long before I gained the weight back. I plan on sticking with this program for the rest of my life.. A “fad” diet? I think not. Averaging 2 lbs per month is generally considered to be a reasonable pace.

[IzzyR]

To clarify the first question a bit: I’m not so much asking if Atkins is right or not. Rather, whether it is indeed true, as is suggested in the article, that his theory was rejected out of hand based on little or no evidence, and that this formed an unrational bias against him for 30 years, until now, as the emerging weight of the evidence is forcing a rethinking? Or were/are there solid grounds for rejecting Atkins, and the antipathy to his theories is based on rational science?

[ultrafilter]

*Originally posted by divemaster *
Well, I love food, but have taken care of myself pretty well. I run 4 miles 4-5 times a week, but in recent years, my (already slow) metabolism slowed down even more and I noticed the weight creeping up on me.

Yeah, this is a pretty typical experience. Despite what we’ve all heard, aerobic exercise in and of itself is not a good way to burn fat. Thing is, when you’re doing a lot of aerobic exercise, you end up burning muscle. Muscle is a very metabolically active tissue-- a pound of muscle burns something like 50 calories an hour when you’re just sitting around. A pound of fat burns about two calories per hour in the same scenario. So as you do more aerobic exercise, it can actually cause your metabolism to decrease. Couple this with the muscle loss due to inactivity (about a half-pound per year), and you can see a major problem arising.

The answer is simple, though: weight training, aerobic exercise, and a reasonable diet. Weight training will cause your muscle mass to increase, thereby raising your metabolic level. Aerobic exercise forces you to burn more calories per pound, and that applies to both fat and muscle–moreso to muscles, because they are providing the force necessary to move you. And the diet gives you the nutrients you need to do all this.

[ultrafilter]

*Originally posted by IzzyR *
**To clarify the first question a bit: I’m not so much asking if Atkins is right or not. Rather, whether it is indeed true, as is suggested in the article, that his theory was rejected out of hand based on little or no evidence, and that this formed an unrational bias against him for 30 years, until now, as the emerging weight of the evidence is forcing a rethinking? Or were/are there solid grounds for rejecting Atkins, and the antipathy to his theories is based on rational science? **

His theories were probably unfairly rejected. Unfortunately, he set himself up as an easy target by making a few ridiculous claims–I mean, he did say that ketosis is better than sex. This was mentioned in the article, IIRC.

[ResIpsaLoquitor]

Hmmmm…if it helps…

I just bought Atkins’ book, coincidentally a few days BEFORE all the fuss was announced this week. I’ve read it up to the part that tells you how to start the diet.

I’m not going to start it until after I see my physician to get checked over…although I am generally healthy, have good blood pressure, and exercise several times a week. Still, I tend to get very tired, and I’m more blobbish in certain areas than I should be. Bottom line is, I could stand to drop about 30 lbs.

I’ll probably start it within the next month, barring any major warnings from my doctor. I’ll let y’all know how it goes.

[tracer]

Just to let y’all know that a lower-fat diet can be effective:

In May 2000 I decided to limit my intake of saturated fat to 20 grams a day. Saturated fat was the only number I watched; I didn’t watch calories, or grams of simple carbohydrates, or even grams of unsaturated fat. Just saturated fat.

In order to make this work, I had to quit eating pizza on a daily basis.

But inside of a few months, my weight dropped from 270 lbs. to 230 lbs.! So something was definitely working.

I haven’t really continued the experiment since then, though, because now I am paying attention to my caloric intake as well as my saturated fat intake. (I’m down to around 210 lbs. now.) But whether it was because of the reduction in saturated fat, the incidental reduction of total fat, or the fact that fatty food also tends to be high-calorie food, a saturated-fat-limiting died worked for me.

[tracer]

Oh, one more thing:

I make absolutely sure not to starve myself. Nothing will kill my motivation to stick to a diet regimen quicker than self-deprivation. When I reach my daily limit of saturated fat grams, I don’t stop eating; I merely have to turn to food that’s saturated-fat-free instead.
[sub]And I wish the FDA would get off their collective duffs about requiring grams of trans-fat to appear on food labels. trans fat is, last I’ve heard, nutritionally equivalent to saturated fat, and I’d like to have the option of limiting my total grams of both saturated and trans fat to 20 per day.[/sub]

[Left_Hand_of_Dorkness]

I read that article, and I felt it pretty badly misrepresented the mainstream dietitians’ position.

I’ve read a fair amount on diets, both as research for being vegetarian and to find out what this funky Atkins thing was that my mom was getting into.

And the ADA, AMA etc. do NOT recommend eating a low-fat, high-carb diet. They recommend eating a diet rich in whole grains, legumes, fresh fruits, and fresh vegetables, with fat making up less than 30% of total dietary intake. They recommend eating a variety of different foods. They recommend making changes to your diet slowly, not dramatically.

Note the whole grains bit. The article mentions this in passing around the sixth page, but it’s really important: whole grains (and legumes, and most fruits and vegetables) contain lots of fiber, which IS filling and satisfying. Furthermore, fiber has all sorts of health benefits. There is no animal-derived source of dietary fiber.

A high-carb diet can consist of sodas and Wonder bread. A whole-grains etc. diet cannot.

The article looked to me like it was setting up one big fat straw man.

Daniel

[tracer]

*Originally posted by *
**I read that article, and I felt it pretty badly misrepresented the mainstream dietitians’ position.

I’ve read a fair amount on diets, both as research for being vegetarian and to find out what this funky Atkins thing was that my mom was getting into.**

I found a half-decent article on mainstream dieticians’ positions – or at least on the vegetarian position – when I was poking around looking for data on the Zone Diet. (Barry Sears’s Zone Diet is similar to the Atkins Diet, except not as extreme; Sears suggests your caloric intake should be 30% fat, 30% protein, and 40% carbohydrate.)

Here is said article:
http://www.vegsource.com/attwood/zone.htm

A high-carb diet can consist of sodas and Wonder bread. A whole-grains etc. diet cannot.

Well, it can contain whole wheat Wonder bread.

The article looked to me like it was setting up one big fat straw man.

Straw is high in fiber too, isn’t it?

[Left_Hand_of_Dorkness]

Straw is, indeed, high in fiber. So is newspaper. Here’s hoping they eat their words.

I’m having trouble finding the American Dietetic Association’s position paper on good eating – all I can find are specific guidelines (e.g., for fiber, for vegetarians, etc.)

However, here are a couple useful ones: on fad diets, and another on healthy weight management. Note that the fad diet fact sheet is pretty clearly referring to Atkins. Although the NYT article makes it seem that the article is off-base (it refers to ketosis as something bad, which the NYT-quoted scientists disagree with), it also makes it clear that the ADA is not recommending a diet low in fish and high in cookies, as the NYT article implies.

Daniel

[Left_Hand_of_Dorkness]

One more interesting link: the US Government’s Nutritional Advice.

Contrary, again, to the article’s suggestion that the high-carb, low-fat diet is some sort of evil American Government conspiracy to experiment on its populace, I’ll quote an exerpt from the World Health Organization’s Nutrition Web Site:

Global trends, nutrition in transition

The emerging epidemics of NCDs are associated with changing dietary patterns, compatible with increased risks of NCDs. **Worldwide, the trends are towards a reduced intake of fruit and vegetables and increased intake of fats (especially saturated fats) and sugar. When associated with reduced physical activity, this leads to increasing weight and growing problems of obesity. **Salt consumption is high in many populations, greatly contributing to elevated blood pressure levels and risk of cerebrovascular strokes. Also, in many populations, intake of fibre is decreasing.

Although undernutrition remains a problem in many developing countries, we see growing rates of overweight and obesity in these same countries. It should be pointed out that nutritional issues behind NCDs are by no means limited to obesity. Many nutrition related problems, e.g. elevated blood cholesterol or elevated blood pressure, can be seen in people with normal weight but unbalanced nutrition.

The changing and unhealthy patterns of nutrition in the world are often linked to so called globalization. While globalization can clearly bring benefits in global poverty alleviation and infection disease control – and is seen by many as inevitable – there are obvious negative consequences for NCD related risk factors, in form of some unhealthy lifestyle changes.

(emphasis mine)

These dietary recommendations are accepted by the international scientific community, and are not some sort of weird mad-scientist plot unique to the US.

Daniel

[IzzyR]

*Originally posted by DanielWithrow *
it also makes it clear that the ADA is not recommending a diet low in fish and high in cookies, as the NYT article implies.

I don’t see where it implies that - it specifically says otherwise:

Surely, everyone involved in drafting the various dietary guidelines wanted Americans simply to eat less junk food, however you define it, and eat more the way they do in Berkeley, Calif. But we didn’t go along. Instead we ate more starches and refined carbohydrates, because calorie for calorie, these are the cheapest nutrients for the food industry to produce, and they can be sold at the highest profit. It’s also what we like to eat. Rare is the person under the age of 50 who doesn’t prefer a cookie or heavily sweetened yogurt to a head of broccoli.

‘‘All reformers would do well to be conscious of the law of unintended consequences,’’ says Alan Stone, who was staff director for McGovern’s Senate committee. Stone told me he had an inkling about how the food industry would respond to the new dietary goals back when the hearings were first held. An economist pulled him aside, he said, and gave him a lesson on market disincentives to healthy eating: ‘‘He said if you create a new market with a brand-new manufactured food, give it a brand-new fancy name, put a big advertising budget behind it, you can have a market all to yourself and force your competitors to catch up. You can’t do that with fruits and vegetables. It’s harder to differentiate an apple from an apple.’’

[SenorBeef]

*Originally posted by ultrafilter *
**It’s very difficult to measure the effects of a specific diet, given the complexity of the human organism, and the incredible variations among people’s reactions to a diet, both across a population and across an individual’s lifespan. Nutrition, as important as it is, is still a fledgling science, and the truth is probably somewhere between the extremes.

That said, I read the article, and I thought it seemed fairly objective. There are a few points I’d like to make:[ol][li] The evolutionary explanation for the low-carb diet does seem reasonable, but that doesn’t mean that any specific low-carb diet is actually good. After all, we can improve upon our situation in the wild in so many ways.[/li][li] Carbohydrates are the main source of fuel used in exercise. While bodybuilders do tend to eat fewer carbohydrates than the general population, most of the ones I’ve encountered still shoot for about 40% of their caloric intake being from carbohydrates (no cite, just my experience). However, they do aim more for complex carbohydrates. Athletes whose primary focus is in endurance are encouraged to get about 60% of their calories from carbohydrates (this is from a book I have on nutrition for endurance athletes).[/li]

**

This is misleading. If I recall correctly, fat can be converted to glycogen (is that the term?) in the muscles and can power them just as well - if not better, than carbohydrate fuels.

The only muscles that actually need sugars to function, I believe, are in the eyes - and even then, your body can synthesize what it needs.

**

[li] There’s some evidence that a diet high in fruits, vegetables, and fiber will reduce the risk of certain cancers and other diseases. You don’t get fruits and vegetables on the Atkins diet, a fact that the author of the article in question pointed out.[/li]

**

This is patently untrue.

First off, the weight loss phase of the Atkins diet is extreme compared to the maintenance phase - and if you truly follow Atkin’s advice, you’ll spend almost all of your time (in life) on the maintenance phase. There are many vegetables that have negligible carbohydrate content, and many that have little - and so you can have a lot of vegetables even on the weight loss phase.

Secondly, the amount of carbohydrates one can heathily consume on the maintenance phase is much higher. The weight loss phase is so strict because it’s trying to maximize weight loss - but once you hit the maintenance phase, you can have plenty of vegetables and a decent bit of fruit, depending on your metabolism.

**

[li] Additionally, the nutritional benefits of phytochemicals (chemicals found in plants that give them their taste, color, etc.) are not well understood, but they probably are important–after all, we are omnivores; we evolved to eat plants as well as meat. There is some evidence that phytochemicals need to be eaten in the ratios that they are found in the original plants.[/li]

**

Atkins encourages eating vegetables, and laster, fruits.

[QUOTE]
**
[li] Fat is a necessary food–the health benefits of nuts and fish are pretty well-documented.[/ol]Those are all generalities, though. At bottom, there is a lot of individual variation in humans with respect to nutrition. You really have to find what works for you, and stick with it. **[/li][/QUOTE]

I guess so, but I’d definitely say universally a low carb diet is better for 99.9% of people than a high carb diet.