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Does dieting cause a reduction in resting metabolic rate? - Open Knowledge — LiveJournal

Feb. 9th, 2007

12:45 am - Does dieting cause a reduction in resting metabolic rate?

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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=6725523&query_hl=29&itool=pubmed_docsum

J Clin Endocrinol Metab. 1984 Jul;59(1):41-4.
Resting metabolic rates of obese women after rapid weight loss.

* Welle SL,
* Amatruda JM,
* Forbes GB,
* Lockwood DH.

Reduced energy expenditure associated with reduced energy intake has been used as an explanation for resistance to weight loss in obese patients. Decreases in serum T3 concentrations and body cell mass induced by restriction of energy intake may contribute to the reduced energy needs. In the present study, mean resting metabolic rate (RMR) was reduced by 9.4% after 5 weeks of a very low energy diet (472 Cal/day) in six obese women, and the mean serum T3 concentration decreased 46%. However, the lowest RMR values measured were similar in these subjects (mean, 1328 Cal/day; range, 1110-1578 Cal/day) to RMR values of lean women (n = 19; mean, 1241 Cal/day; range, 938-1450 Cal/day) and moderately overweight women ingesting ad libitum diets (n = 8; mean, 1335 Cal/day; range, 1064-1533). Decreases in total body potassium (10%) and 24-h urinary creatinine excretion (23%) suggested that there was a substantial loss of body cell mass during weight loss, whereas nitrogen balance suggested that changes in body cell mass were slight. These data and those of previous studies indicate that even after rapid weight loss, the resting energy requirements of obese or previously obese subjects are not abnormally low relative to those of nonobese subjects, even though the concentrations of T3, a major thermogenic hormone, are substantially reduced. The hypometabolic response to weight loss cannot explain the failure of obese subjects to lose weight on weight-reducing regimens.

PMID: 6725523 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11063433&query_hl=31&itool=pubmed_docsum

Am J Clin Nutr. 2000 Nov;72(5):1088-94.Click here to read Links

Comment in:
Am J Clin Nutr. 2001 Mar;73(3):655-8.

Do adaptive changes in metabolic rate favor weight regain in weight-reduced individuals? An examination of the set-point theory.

* Weinsier RL,
* Nagy TR,
* Hunter GR,
* Darnell BE,
* Hensrud DD,
* Weiss HL.

Departments of Nutrition Sciences and Human Studies, the General Clinical Research Center, University of Alabama at Birmingham, and the Mayo Clinic, Rochester, MN, USA. weinsier@shrp.uab.edu

BACKGROUND: Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight. OBJECTIVE: Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain. DESIGN: Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T(3)), and reverse T(3) (rT(3)). Body weight was measured 4 y later, without intervention. RESULTS: Body composition-adjusted RMR and T(3):rT(3) fell during acute (phase 2) and chronic (phase 3) energy restriction (P: < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 +/- 2.0 kg). RMR among weight-reduced women (4771 +/- 414 kJ/d) was not significantly different from that in control subjects (4955 +/- 414 kJ/d; P: = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS). CONCLUSIONS: Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight.

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From:smjayman
Date:February 9th, 2007 05:56 am (UTC)
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So, in summary, odds are good that nobody out there has a "slow metabolism," they just eat more or move less. (If I'm reading all of this correctly?)
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From:crasch
Date:February 9th, 2007 06:11 am (UTC)
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Yes, judging from these studies, dieting doesn't appear to have more than a transient effect on BMR.
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From:resipisco
Date:February 9th, 2007 06:49 am (UTC)
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It would've been nice if they described the diets and body compositions in more detail.
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From:carrie
Date:February 9th, 2007 02:34 pm (UTC)
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What other studies did you come up with for this? Was this a Medline search? You know I'm a big believer in diet and exercise, but current teaching still espouses the set-point theory and I'm wondering why you're posting one 23 year old study and one 7 year old study to make this point.
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From:crasch
Date:February 9th, 2007 04:05 pm (UTC)
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Yes, they're from medline. I was looking for studies on the effects of ultra rapid weight loss. (It would be pointless to lose 30 lbs in a month, for example, only to permanently lower your RMR.) I don't have a strong opinion about set-point theory one way or the other -- I just thought the abstracts were interesting.
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From:carrie
Date:February 9th, 2007 07:41 pm (UTC)
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Pointless? I guess that depends on where you're starting from.
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From:crasch
Date:February 9th, 2007 08:18 pm (UTC)
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All I meant by pointless was that if too-rapid weight loss permanently reduces your RMR, and that in turn causes you to regain all the weight you lost, then I don't see much point in trying to lose weight rapidly. Are you thinking I meant something else?
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From:carrie
Date:February 9th, 2007 09:38 pm (UTC)
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No, I think that's what I thought you meant. I was just looking at it from the perspective of someone who's overweight or obese - if they lose 30 pounds, yeah, their RMR will decrease, but they've also shed the long-term health problems that come from being overweight. I think that's a fair trade. Long-term, yes, people who lose weight rapidly tend to gain it all back and then some, but I think that's a failure of habit change more than anything.
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