NuSI metabolic ward study on low-carb & the insulin hypothesis


I think the study is flawed in attempt to disprove the effectiveness of low-carb diets. To do the study right, they need to have a control group and experimental group of people selected at random. The control group follows the baseline diet, and the experimental group follows the low-carb diet. All other factors in both groups are kept the same. After some time, then the results are measured.

I think those who did this study for political or economic reasons wanted to make low-carb diets appear to fail. As with most diets, the first few pounds are easy to lose. But later in the diet the weight loss seems to stop and go very slowly, usually ending in failure. So it seemed perfect to start the study with every participant on a baseline diet, then end the study with every participant on a low-carb diet. Naturally the low-carb diet fails. Then they talk about how well the baseline diet worked yet the low-carb diet failed. I don’t buy it.

If you have an hour and a half to watch, there is a YouTube video by UCTV by Robert H. Lustig about how sugar and low-fat diet guidelines have caused people to become fat over the past 30 or 40 years. He points out how some studies show the problem and how other studies are flowed, and how government recommendations are based on flowed studies and cause people to become less healthy over the past 30 years.


While there are indeed many ways in which this should be studied, I doubt this particular study was designed to fail… It was, after all, partly funded by NuSI which is a big proponent of low carb.

I do find the theory that the “low fat” craze over the last few decades has accelerated obesity to be rather interesting. A few weeks ago I was going through a bunch of old VHS tapes I made from commercial TV in the 90s (all destined for the trash bin)… It was amazing how just about every food product advertised at that time was promoted as being low in fat. While there was certainly a brief “low carb” craze after that, there is still much work to be done to de-program the anti-fat message.


No, the study was very well-designed to sensitively measure specific metabolic effects of eating a low-carb diet.

Your description makes me think you misunderstood the study when you listed to the video:

The baseline diet was not a weight-loss diet, at all. It was intended to be maintenance calories - causing no weight loss or gain (almost certainly based, in part, on the subjects’ reporting of previous food intake levels.) It was there with the intention of getting people onto an even keel with sensitive measurements of “normal” before switching them to the low-carb version. This was necessary to be able to have a baseline to which to compare the effects of switching to a low-carb diet.

Then they begin the low-carb diet… the dominant theory supporting low-carb and ketogenic diets is that the effects of lower blood sugar and insulin will lead the body to burn more fat, even while eating the same number of calories and getting the same amount of exercise. So this low-carb diet was not intended to be a reducing diet, either… it was just designed to provide the same number of calories as the previous baseline diet. They were trying to tease out the inherent “metabolic advantage” of the low-carb diet, if there was any such advantage… and the study, done in the most sensitive way, found no such advantage.

I found it amusing that the calculated “baseline” number of calories to maintain weight turned out, in reality, to cause weight loss. It’s just another indicator to me that we all tend to eat more than we think we do… unless we’re forced to only consume a certain number of calories.

There’s surely a lot of that going on - people support the studies designed to produce the results they want. You’re mistaken on this one, however. NuSI is an organization formed by major proponents of the low-carb diet, notably including Gary Taubes, who is solidly in the same camp as Lustig. In fact, you can read a Gary Taubes piece in the New York Times where he solidly supports the very video you posted:

The people supporting this study very much wanted to prove one of the underlying mechanisms by which low-carb diets succeed. Sadly for them, the actual results say otherwise.


I still see “low fat” and “no fat” plastered all over products on the shelves today. It’s much harder to find “low carb” products labelled.


Look for “low sugar” and “no sugar.” Everywhere.

It’s hard to do things like cookies and pastry with no carbs, so they don’t bother trying, but you can can do low-fat easily (add more sugar for flavor compensation!)

Most low-carb items are traditionally low-carb and don’t get labels for it - meat, cheese, etc.


Um, “no sugar” can still be 100% carbs.

Why don’t they get labels? Traditional “no fat” items get “no fat” labels like they’re some sort of healthy version:

Answer: there is still a huge cultural bias against fat in product labelling.


Wait, are you saying Swedish Fish aren’t healthy?!?!?!


I didn’t say otherwise.

Same is true of sugar as for fat. There an anti-fat fad, there’s an anti-sugar fad. Both are demonized by large swathes of the population. They’re both just constituents in food.

If you make a crap junk food with no fat, or a crap junk food with no sugar, it’s still crap junk food.

I’ll bet that sugar-free oreos have more fat than regular oreos. And I’ll bet they have plenty of carbs. But hey, no sugar, so it’s healthy, right?


Lol. I remember low fat Oreos. I actually used to eat that crap.

Yes sugar is the new demon, but the anti fat stuff lingers.


How many shades of lipstick can they put on that pig?

My favorite shades are protein and fiber.


Thanks for the reply. I’m sorry it took so long for me to find time to return and read and then post this reply.

I think you missed my point about why I think the study is flawed and the conclusion is flawed. I probably shouldn’t have accused them of being biased, doing so caused people to overlook why the study is flawed.

If I read correctly, the study had all 100 percent of the subjects follow a baseline diet, then later have all 100 percent of the subjects follow a low-carb diet. Then the researchers jump to conclude that all the subjects didn’t expend significantly more energy during the low-carb phase of the study. I finally took my time to watched the video and only find the same flawed study and flawed conclusion. He says low-carb diets don’t help - I DON’T BUY IT. It’s unclear what he says about hunger. He hints that to lose weight you need to eat less and exercise more. I think who designed the study should be fired.

To do the study properly, they could have started with 100 percent of the subjects follow the baseline diet. After two weeks with the baseline diet, they split the group of subject by selecting each at random. The 50 percent selected at random follow the low-carb diet, while the other 50 percent follow the baseline or a normal or low-fat diet. Then after some time they compare the results of the two groups. If the warmer springtime weather made a difference it would effect both groups. If news about the Presidential election made a difference in energy burn it would effect both groups. They would probably find that all did ok during the starting phase baseline diet, losing some weight. Then during the second phase of the study both groups would do about the same in weight loss and energy expenditures, but one group probably would do a little better than the other group. I’d guess the low-carb group would do better than the baseline group. Also in a follow up study, it would be interesting to see if one group did better than the other in keeping the weight off.

The mistake in the flawed study is they had all of the 17 subjects follow a baseline diet than all the same 17 subjects followed a low-carb diet. We don’t know what would have happened if all the subjects remained on the baseline diet. We don’t know what would have happened if all the subjects started with a low-carb diet than went to a baseline diet. We don’t know if the weather, humidity, the super bowl, news about Oprah or any other event could have made more of a difference than the diet during the first or second phase of the study. They should have split the group and compare the two groups side by side, this way we know that the only difference in the two groups is in the diet, then we can conclude if there was a difference in the results.


I’m afraid you still fundamintally misunderstand the study.

You’re talking about a study with control groups, or a comparison study (formally called a “Randomized Controlled Trial,” or RCT.) This would be a good design if they were asking the comparison question, “does a low-carb diet cause more weight loss than a low-fat diet,” or something like that. Or if they were asking, “does a low-carb diet cause weight loss,” they’d also include a control group (i.e., people on baseline diet that stay on baseline diet.)

But they were not asking either of those questions.

This study was funded by a group that already believes that a low-carb diet leads to more weight loss than other diet, so they are not asking that question! The group had a specific theory to explain why a low-carb diet should do better. Confirming their theory relied on very fine measurements, so they designed and funded a study which uses the necessary (and very expensive) procedures to get those very fine details, in hopes of confirming their theory. This study was basic experimental research, not an RCT, and this was not a flaw - it was an intentional design. There weren’t comparing or testing… the were experimentally analyzing.

You seem to be confusing a control group with a baseline measurement.

If you’re doing a comparison study or RCT, you need a control group. But if you’re trying to measure effect size, you don’t want or need a control group. A control group would be a waste of time. But you DO need a BASELINE.

For example, if you wanted to ask the question, “how much does blood pressure rise when a healthy is given an epinephrine injection,” you don’t need to waste time and money taking a control group that isn’t given an injection. You need to give people actual injections and measure their blood pressures.

Of course, to know how much their blood pressures rose, you’d also need to measure them before the injection. That’s where the baseline comes in.

The reason for the baseline diet in this particular study was because it’s not enough to say that, before the study, these people were eating “normally.” There is no normal - people eat all kinds of diets! So they have to be given a specific “normal” diet to establish a solid baseline from which to measure the small changes than can be measured in an expensive metabolic ward study.

To use an analogy, you’re addressing by talking about a sensible study design for the question, “which can be thrown further, a football, or a baseball?” But this study was trying to answer the question, “is it true that the angle of throw for a maximally thrown baseball is just under 45 degrees from the vertical, and if so, exactly how much farther does it go compared to 45 degrees?”

To answer the football/baseball question, you just need a couple of throwers and you measure distances. You don’t care about angles, at all, and it should be obvious which does better.

But for the other question, you’ll need some sort of setup to capture the throws in a way that allows to you carefully measure the angle, as well as the corresponding speeds and distances. And you’d wan’t to establish clear baselines for things like strength of throw and the wind at the time of the throw. And you wouldn’t care at all about the numbers for a football, because that wasn’t what you’re asking about.

Does that make sense?

One more thing I think you’re missing, but which is outside my main points… you said that if the study were 50% kept on baseline and 50% put on intervention, that

A metabolic ward study doesn’t care about external conditions - in this kind of work, the internal conditions are as perfectly controlled as possible so that all you’re measuring is the intended aspect, and the outside has no influence.

But just as importantly, you seem to have the idea that they’d put dozens of people into metabolic wards at once. That’s not realistic. Metabolic wards are scarce and expensive, and only one person can be in the chamber for the entire period. A facility doing the work would likely have one or two chambers. If they have two chambers and 20 study participants, they can only run 2 participants through at a time. They’d need ten days, plus reset time in between each. They can’t test everyone during “the same weather.”

Putting someone through a prescribed-calorie trial for a month were every meal is provided is very expensive, and putting people through metabolic wards is expensive. If you only have enough money and time to put 15 or 20 people through, you’re not going to have half of them skip the intervention. There’s no point in doing that, and all you do is lessen the statistical accuracy of what you learn about the people who do experience the intervention you’re analyzing.


Pics of metabolic ward chambers:

This one shows some of the gas monitoring and management equipment. You need to give the subject oxygen, and take out CO2, but you need to know exactly how much of each.

There are other things you need to provide and take out, too - in this pic, you can see the food-in and poop-out boxes.

And a cheerful inmate. Life on the inside is boring.


One last thing - I don’t mean to imply there’s anything wrong with an RCT, or anything wrong with this sort of experimental study… it’s all good science. They just address different sorts of questions and get different kinds of data.

I think this NUSI metabolic ward study provides valuable data which we wouldn’t otherwise have, because it’s expensive to do, and others have little motivation to spend a lot of money to get this particular fine-grained detail.

I just find it ironic that this NUSI funded this study looking for the fine details they hoped would confirm an underlying theory - they were sure a particular effect was real, but they hoped to show that it was big enough to explain why low-carb is a “better” diet. Instead, the study is telling us that this effect probably isn’t there at all.


I re-watched the video and reviewed things and I’m still not convinced that the NuSI metabolic ward study is a “Gold Standard” or has proven the low-carb insulin hypothesis invalid.

The reason for the need for a control group is the baseline information still needs to be kept track of and compared to the experimental group for the 28 days remaining after the first 15 days. Many or most diets fail because the person suddenly becomes hungry weeks into the diet - and probably has metabolic changes. In your analogy of the baseball vs football throwing study, if someone throws a baseball 15 times, then throws a football 28 times, it wouldn’t be scientific to say the study “proves” that the football can’t be thrown as far - the subjects may simply be tired toward the end of the study in every case. It remains unknown if the difference in measurement data is caused by the person being tired or the type of ball thrown. There is a need to have a control group throw the baseball the remaining 28 times so that can be compared to the experiment group throwing the football 28 times. For the diet study, there are some types of fat on the body that is more metabolically active than other fat. When the metabolic active fat is used up, it may be one of many reasons why weight loss tends to slow AFTER the first 15 days following a diet that causes fat loss. There still needs to be a baseline control group to compare to the low-carb experiment group for the remaining 28 days.

Also it’s unclear if the 80 percent fat 5 percent carbs and 15 percent protein [? 0 percent empty calories] would be significantly different if they did 65 percent fat 5 percent carbs and 30 percent protein. There maybe some things going on from the limited protein during the 28 days of the low-carb diet that may cause the body to go in emergency mode to decrease metabolic expenditures. That may explain why the extra calories burned was only 100 per day instead of the 400 per day they expected for the low-carb diet. If they did a low-carb diet with 30 percent protein, then maybe they’d get the 400 calories per day extra expenditures they expected to find in the 28 days of low-carb diet. Also fiber, flour and many other types of food may play a role in whether or not the low-carb insulin hypothesis would show valid or not.

Thanks for the pictures of the chambers and additional information about the study. They show a lot of details about how the experiment was done. It helped me to know that not all the subjects were tested at the same time - testing one or two of the subjects at different times of the year helps eliminate seasonal variations such as seasonal affective disorder or lengths of daylight hours - at least one chamber has a window in it.

Is why I’m so skeptical of the NuSI metabolic ward study is I’ve seen a lot of studies that are flawed yet they influenced government decisions. Americans spend a lot of money on health care yet they are not more healthy. Another reminder of the failures is I think someone else on this forum may have died after losing control of eating. 400 lb 65 y/o Type II Diabetic & life long food addict, Soylent effects Miraculous

He was overweight and kept on a diet for months and posted regular updates, and then suddenly he lost control of calorie intake and food choices and probable died - his monthly updates suddenly stopped after about two months of rapid uncontrolled weight gain. There are cases like this everywhere, yet the NuSI, NIH, FDA, US Dept. of Agriculture and most people refuse to accept the fact that most people don’t have much control over their diet.

To design a study, I’d want to solve problems so people can be more healthy. Saving a bunch of money in the costs of the study, I’d send participants home with packages of food and record books, have them keep records of hunger, exercise, the times they cheated on the diet and what types of foods they ate/drank when cheating. Periodic collection of records and doing medical tests would track the subjects’ health and ability to control their diet in the real world. This would provide real world information about what foods work and what foods fail in terms of letting people have control over their diet and whether or not they become more healthy. I believe about 250 thousand lives could be saved if Americans had easy access to good food.


You are still crossing the concepts of control groups and baselines:

  • A control group is a separate group of people who don’t have an intervention.
  • A baseline is a measurement of the starting point for an individual.

The baseline measurement for a given person is applicable to that person only, not to anyone else in the group.

Let’s say you and I are doing a study on weight loss, and let’s say you weigh 180 and I weigh 200.

Your baseline is 180, my baseline in 200.

I go on the diet; you don’t. I’m the intervention, you’re the control.

Four weeks later… you may have gained or lost weight, but your baseline is still completely irrelevant to my data. It’s your baseline, not mine. All that matters for my outcome is where I end up after four weeks compared to my baseline.

Clearly, “baseline control group” is just a misnomer.

Moreover, in this study, there is no need for a control group, because we’re not trying to figure out whether the intervention works. We’re not going to compare it to anything. There was only one intervention - low-carb - and the point was simply to get detailed measurements of what it does to a body. It wasn’t going to be compare to anything.

You seem very fixed on the idea of comparing the results of the low-carb diet to the results of the baseline diet… and are clearly defensive about low-carb diets.

I’d like to remind you that this study did not say that (reduced calorie) low-carb diets don’t work for weight loss. It wasn’t about the effectiveness of low-carb diets in any way, shape or form.

It was about the insulin hypothesis underlying current low-carb diet theory. It was designed to answer questions like, “what happens to a body that shifts to running on low-carb?” This was a prospective study about getting detailed measurements about things like insulin response on a eucaloric diet when someone switches from a “standard” diet to a “low-carb” diet. Again, we’re talking eucaloric diets - this was not about weight loss, or they would be on restricted diets instead of eucaloric (staying the same) diets.

This was strictly about getting detailed measurements on the effects of switching the composition of the food you eat, it was not a study of the effects of reducing the food you eat.


If you think the fact that someone gained weight and stopped posting is substantial enough evidence to conclude they’ve died…



I wrote “…may have died after losing control of eating”. I did not conclude the person died. I really hope the person is alive and well and starts posting updates again.

My point was that the person lost control of eating; many people can’t control eating. I concluded that many people, researchers, businesses and government regulators refuse to accept the fact that many people don’t have much control over their diet.


Gary Taubes visited the Sam Harris podcast…

He does lament that in this study they were unable to set up the desired baseline (S.A.D. with sufficient calories to maintain stable weight).


Not at all. In fact there was no “they” concluding anything, as Gary Taubes and Kevin Hall came to completely different conclusions based on the study. In the top video on this page, Mr. Taubes talks about how the study was flawed from the very beginning, including for some of the reasons that @HungerControl was making in this thread.

In the podcast interview that @GregH linked, Mr. Taubes goes into much more detail about the study and why it should have been scrapped very early on; he also talks about the frustration regarding our lack of real knowledge regarding human nutritional needs in spite of over 100 years of mostly well-meaning but misguided study. He points out that we are preparing to colonize Mars and yet we can’t even say with any degree of certainty what is a basic optimum diet for the average human in spite of the fact that we have existed as a species for over 200,000 years. It’s a great interview, as almost all of Sam Harris’s are.