Re: Weight Loss Through Calorie Restriction,But Not Exercise, May Lead To Bone L

[Guest guest]

" CR-induced weight loss, but not EX-induced weight loss, is associated

with reductions in BMD at clinically important sites of fracture.

Despite weight loss, the EX group did not demonstrate a decrease in

BMD at any site. "

They don't say what kind of exercise (likely resistance training) but

here is the actual study abstract:

Bone Mineral Density Response to Caloric Restriction–Induced Weight

Loss or Exercise-Induced Weight Loss

A Randomized Controlled Trial

Dennis T. Villareal, MD; Luigi Fontana, MD, PhD; P. Weiss, PhD;

B. Racette, PhD; Steger-May, MA; B. Schechtman,

PhD; Klein, MD; O. Holloszy, MD

Arch Intern Med. 2006;166:2502-2510.

Background Bone loss often accompanies weight loss induced by caloric

restriction (CR), but whether bone loss accompanies similar weight

loss induced by exercise (EX) is unknown. We tested the hypothesis

that EX-induced weight loss is associated with less bone loss compared

with CR-induced weight loss.

Methods Forty-eight adults (30 women; 18 men; mean ± SD age, 57 ± 3

years; and mean ± SD body mass index, 27 ± 2 kg/m2) were randomized to

1 of 3 groups for 1 year: CR group (n = 19), regular EX group (n =

19), or a healthy lifestyle (HL) control group (n = 10). Primary

outcome measure was change in hip and spine bone mineral density

(BMD). Secondary outcomes were bone markers and hormones.

Results Body weight decreased similarly in the CR and EX groups

(10.7% ± 6.3% [–8.2 ± 4.8 kg] vs 8.4% ± 6.3% [–6.7 ± 5.6 kg]; P =

..21), whereas weight did not change in the HL group (–1.2% ± 2.5%

[–0.9 ± 2.0 kg]). Compared with the HL group, the CR group had

decreases in BMD at the total hip (–2.2% ± 3.1% vs 1.2% ± 2.1%; P =

..02) and intertrochanter (–2.1% ± 3.4% vs 1.7 ± 2.8%; P = .03). The CR

group had a decrease in spine BMD (–2.2% ± 3.3%; P = .009). Despite

weight loss, the EX group did not demonstrate a decrease in BMD at any

site. Body weight changes correlated with BMD changes in the CR (R =

0.61; P = .007) but not in the EX group. Bone turnover increased in

both CR and EX groups.

Conclusions CR-induced weight loss, but not EX-induced weight loss,

is associated with reductions in BMD at clinically important sites of

fracture. These data suggest that EX should be an important component

of a weight loss program to offset adverse effects of CR on bone.

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