Here's the study:
Effect of a Low-Fat, High-Fiber Diet and Exercise Intervention on Breast Cancer Risk Factors and Tumor Cell Growth & Apoptosis, Nutrition and Cancer, 2006
"The subjects of this study were postmenopausal women attending the Pritikin Longevity Center Residential Program where they were given a low-fat (10-15% Kcal.), high-fiber (>40 gm/d) diet along with one hour of daily supervised exercise, primarily treadmill walking. The diet consisted of natural whole grains, fruits and vegetables with limited amounts (<3.5 oz) of fish, fowl or lean meat and nonfat milk."It wasn't a diet devoid of animal food, although animal food was substantially scaled back.
Estrogens, insulin, and insulin-like growth factor-I (IGF-I) all stimulate the growth of breast cancer cells. In this study, women experienced marked reductions in all of these markers. Not only that, the blood of women who underwent the diet-plus-exercise for 13 days slowed the growth of plated cancer cells and caused an increase in cancer cell suicide (apoptosis), compared to their blood at the beginning of the study.
Dr. Michael Greger describes the results of this and another similar study involving prostate cancer that I discussed on this blog several years ago. In that study, the blood of men in the treatment group inhibited the growth of prostate cancer cells 8 times more than blood of men in the control group.