-Reduces body fat and maintains muscle
-Critical Essential Fatty Acids (EFA) are missing in our diet

from "Rust Out" by Dr. Royce Bailey, page 32

Pills and potions that promise to slim you down are a dime a dozen and there’s very little scientific evidence to support their potential benefits or harm.  CLA, developed and patented by scientists at the University of Wisconsin Food Research Institute have changed all that!  Changes in the food people eat and the way cattle (the source of beef and most dairy products) are raised, have lowered the amount of EFA-CLA in the American diet (the American paradox).  People are getting less EFA in their diets and Americans are seeing a substantial increase in body fat levels. There is a growing, cultural trend to eliminate dietary fat.  However, EFAs are critical and vital to good health. These are basic requirements, because they cannot be manufactured by the body, but must come from dietary sources or supplements. Modern processing techniques remove many of these essential oils from our foods.

71 obese men and women on a diet and exercise program were given 3 grams of CLA (two 500 mg caps with each meal) or placebo.  After 6 months, all subjects were about 5 pounds lighter, but the CLA takers reported:

1.  Easier time staying on their diets
2.  Experienced fewer hunger pangs
3.  Any weight they did gain back during the common fluctuations of dieting was mostly lean muscle (the others gained back mostly fat).
“This is a big difference, their weight might not have changed much, but they were slimmer,” said Dr. Michael Pariza author of the study.

CLA works in several ways:
1.    It doesn’t make people lose body fat faster, but it does keep little fat cells from getting bigger.  (By repression of Steroyl-CoA desaturase gene expression in adipose cells by the trans-10, cis-12 isomer in CLA).
2.    The supplement helped people emotionally-with their mood and concentration (dieting is stressful).
3.    CLA appears to have an anti-cancer effect (anti-oxidant?)
4.    CLA has an anti-atherosclerosis function.
5.     CLA enhances your immunologic function (modulates cellular response to Tumor Necrosis Factor alpha (TNF-a) and has been shown to protect against end-stage Lupus).

Early studies in humans showed little effect from CLA, because all 24 isomers, or a 50-50 mixture of trans-10, cis-12 and cis-9, trans-11 isomers was used.  Trans-10, cis-12 isomer positively alters the body composition and should be the isomer used.

Other EFAs that have been shown of benefit include: Flaxseed Oil, Evening Primrose Oil, Borage Oil, Black Currant Seed Oil, Fish oil (DHA/EPA essentials), Neuromins (vegetable sourced DHA).

References:
Park,Y., “Effect of Conjugated Linoleic Acid On Body Composition in Mice,” Lipids, August 1997;32(8):853-858.
Pariza,M., “Mechanisms of Action of Conjugated Linoleic Acid: Evidence And Speculation,” Proc Soc Exp Biol Med, January 2000; 223(1):8-13.
Pariza,M.,“Conjugated Linoleic Acid And The Control Of Cancer And Obesity,” Toxicol Sci, December 1999; 52 (2 suppl): 107-110.
Yang, M., “Dietary Conjugated Linoleic Acid Protects Against End Stage Disease  Of Systemic Lupis Erthematosus In The NZB/W F1 Mouse,” Immunopharmacol Immunotoxicol, August 2000; 22(3): 433-439.
“Can A Supplement Really Help Dieters?” Health, Nov/Dec 2000; 24.