10% CR increases longevity even when started in adulthood.

[Guest guest]

.... and macronutrient composition doesn't seem to matter. Al Pater

found this abstract.

==============

Obes Res. 2005 Apr;13(4):693-702.

Intentional weight loss reduces mortality rate in a rodent model

of dietary obesity.

Vasselli JR, Weindruch R, Heymsfield SB, Pi-Sunyer FX, Boozer CN,

Yi N, Wang C, Pietrobelli A, DB.

Department of Biostatistics, University of Alabama, Ryals Public

Health Building, Room 327, 1665 University Boulevard, Birmingham,

Alabama 35294-0022. Dallison@....

OBJECTIVE: We used a rodent model of dietary obesity to evaluate

effects of caloric restriction-induced weight loss on mortality rate.

Research Measures and Procedures: In a randomized parallel-groups

design, 312 outbred Sprague-Dawley rats (one-half males) were assigned

at age 10 weeks to one of three diets: low fat (LF; 18.7% calories as

fat) with caloric intake adjusted to maintain body weight 10% below

that for ad libitum (AL)-fed rat food, high fat (HF; 45% calories as

fat) fed at the same level, or HF fed AL. At age 46 weeks, the

lightest one-third of the AL group was discarded to ensure a more

obese group; the remaining animals were randomly assigned to one of

three diets: HF-AL, HF with energy restricted to produce body weights

of animals restricted on the HF diet throughout life, or LF with

energy restricted to produce the body weights of animals restricted on

the LF diet throughout life. Life span, body weight, and leptin levels

were measured. RESULTS: Animals restricted throughout life lived the

longest (p < 0.001). Life span was not different among animals that

had been obese and then lost weight and animals that had been nonobese

throughout life (p = 0.18). Animals that were obese and lost weight

lived substantially longer than animals that remained obese throughout

life (p = 0.002). Diet composition had no effect on life span (p =

0.52). DISCUSSION: Weight loss after the onset of obesity during

adulthood leads to a substantial increase in longevity in rats.

PMID: 15897478