Study:Metabolic Slowing with Massive Weight Loss

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mikefarinha

Joined: Jun 11
Posts: 443

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Posted: 27 Apr 2012, 18:37
Interesting study.
http://jcem.endojournals.org/content/early/2012/04/24/jc.2012-1444.abstract

Quote:
Conclusions: Despite relative preservation of FFM (fat-free mass), exercise did not prevent dramatic slowing of resting metabolism out of proportion to weight loss. This metabolic adaptation may persist during weight maintenance and predispose to weight regain unless high levels of physical activity or caloric restriction are maintained.


So it seems that exercise doesn't affect metabolic rate. Losing weight through caloric restriction slows down ones metabolism.

I don't have full access to the study but I wonder what type of exercise they used; cardio or resistance training. Probably cardio.

-Mike
"Eat as if your life depends on it!"
Nimm

Joined: Dec 10
Posts: 669

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Posted: 27 Apr 2012, 18:58
mikefarinha wrote:
So it seems that exercise doesn't affect metabolic rate.


I don't think that conclusion is necessarily justified from the abstract; if the subjects did proper resistance training and had sufficient dietary protein, they almost certainly retained more of their LBM than they would have, if they hadn't lifted while dieting. And their final RMR was therefore probably higher than it would have been otherwise. If they didn't go through proper resistance training with sufficient protein, then they certainly lost more LBM than they would have otherwise.

Quote:
Losing weight through caloric restriction slows down ones metabolism.


It's been known for a while that a person who diets down to a certain weight will usually have a lower RMR than someone at that same weight who did not diet down to it. It's the extra bonus metabolic handicap we all face after losing weight. It's been measured at around roughly 150 calories/day or so, in the past, for less weight loss than in this study. These folks had a final metabolic handicap of around 500 calories - probably about right for the amount of mass they lost.

See: Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight.


Quote:
I don't have full access to the study but I wonder what type of exercise they used; cardio or resistance training. Probably cardio.


Given that the weight loss was 83% fat and 17% LBM, that's probably right. Or at least, a combination of cardio and a not-very-effective resistance training program. These were extremely obese subjects that underwent massive weight loss. Obese untrained beginners are the lucky few who can actually grow new muscle mass while losing fat, given enough protein and the right resistance training.

It would be interesting to see the full study...
Eringiffin

Joined: Mar 12
Posts: 117

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Posted: 27 Apr 2012, 19:05
How depressing. If I read this correctly, once you lose a lot of weight, you cannot go "off" of the diet, ever. Or risk gaining the weight back. Well, that seems to make sense considering the yo-yo effect that so many people experience. I'm saying my goodbyes to carbs forever. *sniff* I am also interested in what type of exercise they used. If more muscle was added, shouldn't that help with calorie burning?
MillaLite

Joined: Feb 08
Posts: 148

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Posted: 27 Apr 2012, 21:41
Eringiffin -- please don't let this get you down! You just keep doing what you are doing! You are steady losing NOW and that's what matters.
** You can’t solve a problem with the same mind that created it. –Albert Einstein **
Ingria

Joined: Oct 11
Posts: 530

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Posted: 27 Apr 2012, 22:49
All studies I read so far indicate the same. While I believe, that people who lost weight are at a disadventage, there is also a possibility that they always were, and that was one of the major reasons for weight gain in the first place.

Also there is no conclusive answer on how many more calories a pound of muscles burn per day but results vary from a dismal 6 cal to about 30. I doubt that I would be able to gain enough muscle mass through any amount of weight lifting to compensate for decreased BMR related to weight loss and aging. I am afraid I will remain a loyal FS member for many years to come melting those stubborn pounds.
~~~~~~~~~~
The first thing you lose on a diet is your sense of humor. ~ Author Unknown
It doesn’t matter what diet you follow… What matters is what makes you follow your diet. ~ Tom Venuto
mikefarinha

Joined: Jun 11
Posts: 443

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Posted: 28 Apr 2012, 00:11
Eringiffin,

Don't get discouraged. I think the problem with studies like these is they assume that losing weight is all about caloric restriction instead of looking at it like a metabolic disease that needs to be healed. IMHO When someone simply cuts calories they're not trying to fix the problem but rather treat a symptom.

The results of this study are not surprising at all. Just think about it logically. If your body is experiencing a famine (aka caloric restriction) what should it do? Use up all of it's reserves or slow down the metabolic rate so it will need less fuel?

To me it seems logical that typical body fat reserves are used to allow us to survive for a day or two after a bad hunt. Kind of a short-term reserve. A long term famine on the other hand would require a different metabolic approach to allow us to survive as long as possible. Slowing down our metabolism would allow us to survive on little food for a longer period of time. One of the benefits of this is reduced hunger and increased focus. However when the famine is over what do you think the body wants to do?

This is one of the reasons I'm starting to get interested in reading up on intermittent fasting (IF). It is a way to emulate evolutionary situations that we're adapted to. However I still don't know a whole lot about it.

Nutrition and metabolism are far more complicated than many authorities lead us to believe.

-Mike
"Eat as if your life depends on it!"
Eringiffin

Joined: Mar 12
Posts: 117

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Posted: 29 Apr 2012, 22:33
Mike,

I have to agree with you about nutrition and metabolism being complicated. Additionally, it seems like there is a lot of mis-information floating around. Everyone has a different belief in what foods are good, what will increase or decrease your metaboism, etc. Sometimes I really feel like I am being hunted by opportunists looking to take advantage of my desire to lose weight. I've sort of given up on finding the "right" way to lose weight and still be healthy. I am just focusing on any way to get this weight off and get back to being able to do all the things I want to do in life.

What I take away from this study is that "diets" don't work. I have to commit to making lifelong lifestyle changes. That, and get to the bottom of how I got here in the first place to avoid history repeating itself.
mikefarinha

Joined: Jun 11
Posts: 443

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Posted: 30 Apr 2012, 09:48
Nimm wrote:
mikefarinha wrote:
So it seems that exercise doesn't affect metabolic rate.


I don't think that conclusion is necessarily justified from the abstract;


Nimm, but that is exactly what was stated in the abstract:

"exercise did not prevent dramatic slowing of resting metabolism out of proportion to weight loss."

-Mike
"Eat as if your life depends on it!"
Nimm

Joined: Dec 10
Posts: 669

      quote  
Posted: 30 Apr 2012, 10:04
mikefarinha wrote:
Nimm wrote:
mikefarinha wrote:
So it seems that exercise doesn't affect metabolic rate.


I don't think that conclusion is necessarily justified from the abstract;


Nimm, but that is exactly what was stated in the abstract:

"exercise did not prevent dramatic slowing of resting metabolism out of proportion to weight loss."


This is just a semantic issue, I think. Your resting metabolic rate is affected significantly by the amount of lean mass you have. Resistance training will in turn affect that - either to grow more lean mass during a calorie surplus, or to preserve more lean mass than would otherwise be lost during a calorie deficit.

If you meant that whatever exercise was done in this study doesn't prevent the "bonus" slowdown out of proportion to lean mass then yes, that's right. Nothing does - or at least, I'm not aware of any research right now establishing that any type of diet or exercise will prevent this slowdown. You lose mass, and you will likely burn fewer calories at rest than someone with an identical body composition who didn't diet down to that weight. I don't know if anyone has determined whether the this penalty is permanent, and if not, what factors other than time can correct it.

What's more interesting is that the slowdown in resting metabolic rate (beyond simply having less mass) is small compared to the reduction in total daily energy expenditure. Your total calorie burn will drop significantly, because most people will, without knowing it, reduce their total activity level. It's likely an energy-conservation measure in response to a calorie deficit.
But, forewarned is forearmed - we can offset that by consciously staying more active, even if it isn't exercise activity.

mikefarinha

Joined: Jun 11
Posts: 443

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Posted: 30 Apr 2012, 11:36
Nimm, I think we're on the same page.

With only the abstract to go off of we can't know what we can't know. In my initial post I didn't try to put any commentary on the study just relate what was said in the abstract.

From what it looks like it seems the study only focused on the calorie in/calorie out paradigm which is solely about energy consumption & energy expenditure. Assuming that, I'm sure it didn't matter to these researchers what type of exercise is used. Just like many nutritional authorities like to tell us that a calorie is a calorie; it doesn't matter how it is consumed or how it is burned.

You and I both know that is a bad assumption. Resistance training (esp HIIT) IMHO, is the most effective type of training to improve ones health ,not that cardio also doesn't have an important role, and if they focused on building lean mass they probably would have had better results.

The assumption that you make that I disagree with is that the reduced activity level, after a typical caloric-restriction weight loss, is something that can be improved/increased with vigilance. The body reduces the metabolic rate for a reason and that reduction in metabolic rate is accompanied by a reduction in energy levels. To say that awareness and vigilance is the key is not really listening to what the body is trying to say and just continues to encourage people to fight their body instead of listening to their body. That is like lifting a rock in the air and expecting it to say in the air once you let go. The rock will only stay in the air as long as you hold it up; but who wants to spend their life holding a rock in the air? Plus some people have bigger rocks than others.

I expect that the future of health & nutrition will eventually revolve around emerging sciences such as Nutrigenomics and Epigenetics. However I don't expect this shift to happen anytime soon as there is too much momentum in our current system and too high a signal-to-noise ratio with diet and nutrition information for the average person to make an informed decision.

-Mike
"Eat as if your life depends on it!"
Nimm

Joined: Dec 10
Posts: 669

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Posted: 30 Apr 2012, 12:21
mikefarinha wrote:
Resistance training (esp HIIT) IMHO, is the most effective type of training to improve ones health ,not that cardio also doesn't have an important role, and if they focused on building lean mass they probably would have had better results.


I can't quite agree with that. First, high-intensity interval training is cardio, so I'm not sure what you meant by that. Second, I don't think a blanket statement that lifting is categorically "better" for health than cardio is defensible. It's going to vary a lot from person to person, based on individual circumstances and health status. Cardio is very overrated (and isn't even necessary) for weight loss purposes, but it has demonstrated health benefits. There are plenty of recreational and professional lifters out there whose health would improve more from an hour of cardio, than an extra hour of lifting, for example. Balance and moderation.

But having said that, yes, if I had to pick, the population concerned with body fat loss should generally focus more on resistance training than cardio. Ultimately, though, the best exercise regime is going to be whatever the person enjoys and is happy to stick with.


Quote:
The assumption that you make that I disagree with is that the reduced activity level, after a typical caloric-restriction weight loss, is something that can be improved/increased with vigilance.


Of course it can. Unless you don't have volitional control over your body, you can choose to increase your activity level, in ways that do or do not involve exercise. This isn't necessary for weight maintenance, as you can also just consume fewer calories. Or you can do a combination of the two. But unless and until research demonstrates a way to prevent the unintentional reduction in activity (and, therefore, TDEE) that comes with loss of body mass, it's a reality of life. If research demonstrates that a particular dietary regime prevents this from happening, wonderful. But until then, it's something to be aware of, regardless of which dietary strategy is used to reduce weight.

Quote:
The body reduces the metabolic rate for a reason and that reduction in metabolic rate is accompanied by a reduction in energy levels. To say that awareness and vigilance is the key is not really listening to what the body is trying to say and just continues to encourage people to fight their body instead of listening to their body.


I don't know what you mean with your claim that increasing your activity level is "fighting your body" or "not listening to your body." If I take the stairs at work instead of the elevator, I don't consider that "fighting" my body. Same for standing while talking on the phone instead of sitting. Or walking to the corner store instead of driving. If someone prefers to maintain a lower activity level (or must, because of injury or other condition), then the calorie consumption has to be correspondingly lower.

Unless definitive contrary research comes down the pike, losing weight through whatever means results in a lower total daily calorie burn, compared to someone with equivalent body composition who did not diet down to that point. Some of that reduction in energy expenditure is hormonal and we don't yet know if it can be prevented, or how. Most of the lower TDEE, however, is from unintentional reduction in activity level, and more efficient movement that uses less energy. With a reduction in TDEE, we have to move around a little more, eat slightly fewer calories, or both.

There's a lot of money and prestige to be earned for whomever demonstrates how to prevent this from happening in the first place, or how to ameliorate its effects without increased activity or reduced calorie intake. Until then, though, it remains wishful thinking or merely guesswork.

EDIT: Adding, the big picture here is that once someone has lost a significant amount of weight, their RMR is going to be lower anyway simply because of the change in mass. So to maintain the lower mass, that person will already be consuming fewer calories than before the weight loss, and/or increasing total activity. The marginal reduction in RMR only changes that by a small amount.



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