Researcher have show that excess weight and weight gain during adult life increases the risk diabetes, cardiovascular disease (CVD), dementia, and certain forms of cancer, including breast cancer. As such, weight gain has directly been associated with with an increase premature death. Observational and some randomised trials suggest that modest weight reduction (>5% of body weight) reduces the incidence and progression of many of these diseases, including a number of cancers.

An intermittent, low-carbohydrate diet was superior to a standard, daily calorie-restricted diet for reducing weight and lowering blood levels of insulin, a cancer-promoting hormone, according to recent research findings.

Researchers at Genesis Prevention Center at University Hospital in South Manchester, England, found that restricting carbohydrates two days per week may be a better dietary approach than a standard, daily calorie-restricted diet for preventing breast cancer and other diseases, but they said further study is needed. ?Weight loss and reduced insulin levels are required for breast cancer prevention, but [these levels] are difficult to achieve and maintain with conventional dietary approaches,? said Michelle Harvie, Ph.D., SRD, a research dietician at the Genesis Prevention Center, who presented the findings at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 6-10, 2011.

Weight loss and blood markers of breast cancer risk
Harvie and her colleagues compared three diets during four months for effects on weight loss and blood markers of breast cancer risk among 115 women with a family history of breast cancer. They randomly assigned patients to one of the following diets: a calorie-restricted, low-carbohydrate diet for two days per week; an ?ad lib? low-carbohydrate diet in which patients were permitted to eat unlimited protein and healthy fats, such as lean meats, olives and nuts, also for two days per week; and a standard, calorie-restricted daily Mediterranean diet for seven days per week.

Insulin resistance
Data revealed that both intermittent, low-carbohydrate diets were superior to the standard, daily Mediterranean diet in reducing weight, body fat and insulin resistance. Mean reduction in weight and body fat was roughly 4 kilograms (about 9 pounds) with the intermittent approaches compared with 2.4 kilograms (about 5 pounds) with the standard dietary approach. Insulin resistance reduced by 22% with the restricted low-carbohydrate diet and by 14% with the ?ad lib? low-carbohydrate diet compared with 4% with the standard Mediterranean diet.

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?It is interesting that the diet that only restricts carbohydrates but allows protein and fats is as effective as the calorie-restricted, low-carbohydrate diet,? Harvie said. She and her colleagues plan to further study carbohydrate intake and breast cancer.

This study was funded by the Genesis Breast Cancer Prevention Appeal.

For more information:
Presenter: Michelle Harvie, Ph.D., SRD
Abstract Number: P3-09-02
Title: Intermittent Dietary Carbohydrate Restriction Enables Weight Loss and Reduces Breast Cancer Risk Biomarkers.

Harvie MN, Pegington M, Mattson MP, Frystyk J, Dillon B, Evans G et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int.J Obes (Lond) 35; 714-27, 2011.

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