New evidence has been revealed on how the ‘warrior diet’ style of intermittent fasting impacts on female hormones in pre and post-menopausal women.
This style of dieting involves a ‘window’ of four hours a day when participants can eat without calorie counting, before sticking to just water until the following day.
While it has been proved to be a good way to lose weight, there have been concerns about the effect it may have on female hormones.
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Now a research team from the University of Illinois Chicago has presented new findings after measuring hormone levels in a group of pre and post-menopausal obese women over eight weeks. Some of the women followed four and six-hour feeding windows while a control group did not have any diet restrictions.
The team made a number of key findings, one being that the protein which carries reproductive hormones throughout the body – the sex-binding globulin hormone – remained unchanged in the fasting women at the end of the eight weeks. The same results were found for testosterone and androstenedione, a steroid hormone that is used to produce testosterone and oestrogen.
However, the team did find significantly lower levels of dehydroepiandrosterone (DHEA), a hormone used by fertility clinics to boost ovarian function and egg quality, in both the pre-menopausal and post-menopausal women at the end of the eight weeks. These levels were found to have dropped by about 14%. The team noted that despite the drop, levels of DHEA remained in the normal range.
Research leader Krista Varady, a professor of nutrition, commented: “This suggests that in pre-menopausal women, the minor drop in DHEA levels has to be weighed against the proven fertility benefits of lower body mass.
“The drop in DHEA levels in post-menopausal women could be concerning because menopause already causes a dramatic drop in oestrogen, and DHEA is a primary component of oestrogen. However, a survey of the participants reported no negative side effects associated with low oestrogen post-menopause, such as sexual dysfunction or skin changes.”
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The team said that a small drop in DHEA levels may benefit pre and post-menopausal women as high DHEA has been associated with a risk of developing breast cancer.
The study found that in both fasting groups, the women achieved 3% to 4% weight loss, while the control group saw virtually no weight loss. There was also a drop in insulin resistance amongst the fasters.
The study has been published in the journal Obesity.