The study above was published in 2012. Regardless of the results (which support my assertion), the fact that they are even doing this study (partially funded by the National Institute of Health which means that it was peer reviewed by experts in the field before grant was given to do the study) suggests that this was a question there wasn't a definitive answer at this point and there were still nutritional questions.

"The results of our study challenge the notion that a calorie is a calorie from a metabolic perspective. During isocaloric feeding following weight loss, REE was 67 kcal/d higher with the very low-carbohydrate diet compared with the low-fat diet. TEE differed by approximately 300 kcal/d between these 2 diets, an effect corresponding with the amount of energy typically expended in 1 hour of moderate-intensity physical activity."

They can do all the studies they want, if I'm at a calorie deficit regardless of the type of food, I lose the same weight, and for me thats good enough. I don't need to add anything else to complicate my diet and have me fall off the wagon from the food limitations lol

I absolutely agree. You need to create the deficit. You don't need to complicate your life. Particularly if you are also eating for health and variety and generally eating a diet that includes all the macronutrients.

I just like understanding and knowing - it helps me make better decisions.

I agree. I have no doubt that differences between protein metabolism and carb metabolism, etc., are real. IN PRACTICAL TERMS, however, the difference in weight loss between going higher carb or lower carb (given the same amount of calories) will be quite small for most of us.

Freelance

Which assertion you're made does this study support? (You've made several in this thread)

I've not had the opportunity to read this study in depth but at first glance it appears to have a small sample size and protein consumption was not matched. Not saying it is a bad study but it may not be saying the things you think it is. At first glance it appears to support the idea that insulin resistant people will burn fewer calories on a higher carb diet.

A lot of these studies seem to be poorly done XD

Hi John, I'm not sure I've made that many assertions besides the one that what you eat (and specifically the macro-nutrients) can influence how many calories you burn. Other discussion has just nitpicked details on that assertion (e.g. insulin response and what that does, etc.). This particular study suggests that diets made up of different macro-nutrients resulted in changes in both resting energy expenditure and total energy expenditure (not sure why they would match the protein consumption as you suggest, that is kind of what they were testing)

You are right - there are issues and limitations in the study as in all studies. It is a small sample size. However, even with the small sample size, the effect sizes were big enough that they got statistically significant results. This is a peer reviewed article in JAMA - a well respected highly competitive journal with a really high impact factor (impact factor is sort of a measure of how well respected a journal is and how often it gets cited by other academics). I promise you if this was a crap study, it would not get into JAMA. But as in all studies, there is potential that random chance alone would find these results even if there is no difference between the groups. And for sure, there are a LOT of limitations. In fact, there are a couple of followup letters in the journal questioning some of the statistics in this particular study. My area of expertise is research methodology and statistics - so I am acutely aware of the limitations when reading studies - and of the fact that there are a lot of crap studies out in the world.

But you are sort of missing my point. I am asserting that there may very well be (and there is some good evidence to suggest) physiological reasons that in some ways, a calorie is not a calorie and that the composition of calories CAN make a difference. Even if the study is so flawed we don't trust anything about it (which I don't think should be the case), clearly the researchers who bothered to do the study thought it was a possibility that calorie composition impacted energy expenditure, as did the expert grant reviewers, as did Action editor at JAMA, as did the peer reviewers ...... The results of the study may support this possibility. But even if we wanted to write off the results due to poor design (actually great design IMHO, some bad stats and interpretation though) - a multitude of experts are saying that nutritional composition effecting energy expenditure is a possibility simply by virtue of conducting the study, funding the study, and publishing the study. So why are you so sure you are right that "a calorie is a calorie is a calorie" and that they can't possible be effected by the composition of those calories. This isn't the only study - there are a lot of studies that show that the nutritional makeup from your food can effect the energy output of the equation. And at one point earlier in the thread, I thought you agreed with that assertion.

Yes you need an energy deficit to lose weight. And, I totally agree with Cherry Quinn - for the average person who is losing weight no problem, there is no reason to get worked up about all of this and think about this. Eat a diet that also promotes good health and not just weight loss (you need fat, carbs, and protein; you need fruits and vegetables), and this is not something you need to worry about. Create a deficit you will lose weight. Even if you only eat twinkies, create a deficit you will lose weight. That I know you agree with. What I am saying, is that if you only eat twinkies, to create that deficit, you may actually have to eat less calories than you would if you ate differently. What you eat matters in regards to how much energy output you have.

So to be simple, this is not something to worry about. But if we are going to be technical, I want to know the most correct answer there is, and I think that the science generally supports the notion that not all calories are the same.

I wasn't gonna say anything but some of the things you have said just bothered me. Small sample sizes are bad...very bad and just because a scientist has an hypothesis does not mean theres some credit to it even if the results aren't there. Thats why they get tested over and over and over and over in double blind studies with large sample sizes...What science do you study exactly?

Yes, double blind studies are the gold standard. I agree. That is not always possible (or necessary). And yes, large sample sizes are better - not always necessary, particularly for large effect sizes (that is why you conduct a power analysis before a study and why grants require a power analysis) . And yes, just because a scientist has a hypothesis does not mean it gives it some credit even because the results aren't there. But, a scientist can't get a grant without evidence that there hypothesis is at least an actual viable question that 1) hasn't been completely answered and usually, 2) has been shown that there is literature to support that it may be true. That is the info you put in a grant - the literature leading up to the formation of the new research question. Does this one particular study PROVE that calories impact that output end of the equation? ABSOLUTELY NOT. Does it suggest that this is at least a viable research question that hasn't been definitively answered even though John seems to think it has - I think it does. And there are a TON of studies in the last few years validating and supporting this idea - all with different methodology. I believe the literature empirically supports my claims.

To answer your other question. I study quantitative psychology. Specifically, my research interests are statistical analyses when there are missing data, planned missing data research designs, longitudinal designs, and mediation analysis (mediation analysis is analysis of a causal chain where some mediator, M, impact the relationship between X and Y such that X causes M causes Y). Mainly my application applies to health and prevention research.

I really don't agree that these imo poorly done studies prove anything and them just being there cause the 'scientists' received grants doesn't prove anything either. But thats my opinion.

I am asking you to consider that this proves this is an area that is not fully understood. Not that I am necessarily right.

And what poorly done studies? I just showed you one. There are a lot of studies on this topic and similar. My perusal of the literature suggests that these support my belief. I am no means a subject matter expert on this though and could be wrong. Plus, I don't think the field has actually worked out all these answers definitively. What is sort of bothering me, is how adamant you and John are that there is no way I am right when it seems clear that there is evidence that this is at least a question worthy of consideration.

PS I am also curious how you would propose to double blind a study like this one ..... double blind would imply that the participants didn't know what food they were eating ....

To clarify my position, I personally think that:

Macronutrient composition does not affect RMR but does affect TEF and can affect SPA and NEAT.

Translation:

What you eat can affect your energy levels but not your metabolism. Energy levels can affect the calories one burns through non exercise movement.

Insulin resistant people will burn more calories on a low carb diet because they'll have higher energy levels.

Many of the studies done on this topic in the past did not match protein. (Including this one) First, we know protein has a higher TEF. Second, many of these studies are not ward studies and we know protein has a much higher satiety level. (People lie about their actual intake) Third, most of these studies are hypocaloric and protein is the most LBM sparing. I'm just speaking in general, not about any specific study.

There is no doubt that there is debate amoungst the scientific community regarding macronutrients and energy output. What I said is that I rarely find studies confusing or contradictory. I am not an expert, I just have common sense and a basic understanding of how the body works.

I find the notion from some posters here that macronutrients don't matter because it doesn't affect them pretty silly. Just as I find the notion that macronutrient composition matters to everyone silly. What seems to make the difference is insulin resistance. Generally I don't think it makes much difference in most people from a energy utilized perspective but I do think it makes a tremendous difference in most people from a compliance perspective due to saiety.

Not many areas of a lot of things are fully understood lol I refer to studies as studies done on this topic in general. Proving that this is a science not fully understood yet does not in any way shape or form prove your theory right. The way you talk is very confusing. Very. You want for us to agree but I'm not even sure what it is you are trying to prove , and a question existing of whether or not something is true or not does not prove something correct...I am not saying you are wrong because you're exact position is unclear and mine is simply that there has not been enough quality studies done to prove one way or the other that eating certain foods will cause me to lose more weight and regardless in my experience the types of food i eat has not effected my weightloss whether its healthy foods or not .
I can think of plenty of ways really but a double blind was just an example. I think a lot of scientists look for the evidence to prove their hypothesis rather than being objective, as a student of psychology you would know that.

Actually what interested me in this study was the rise in cortisol levels in the very low carbohydrate group... and it's possible effects... Not only on maintaining weight loss, but also its other possible negative health effects...