Meal Timing Can Improve Fertility in Women with PCOS


Between one in 10 and one in 20 women of childbearing age have PCOS – Polycystic Ovary Syndrome – a health problem that starts with a hormonal imbalance but can lead to concerns such as abnormal menstrual cycles and problems with fertility.

Researchers believe that insulin may be linked to PCOS as many women with the condition have excess insulin levels and a decreased ability to effectively use the hormone (they are insulin resistant). The overabundance of insulin makes its way to the ovaries, where it stimulates the production of testosterone, which is one factor in impairing fertility.

There is no cure for PCOS, but treatment to manage symptoms includes lifestyle modification including the adoption of a healthful diet – one that limits processed foods and foods with added sugars. This helps to lower blood glucose levels, improve the body’s use of insulin, and normalize levels in the body. Those who are overweight are encouraged to lose the extra pounds as even a 10% loss of body weight can restore a normal period and make the menstrual cycle more regular.

Researchers with Tel Aviv University have another suggestion for women with PCOS. Professor Daniela Jakubowicz suggests that the timing of meals may be critical in lowering insulin levels. Women with the condition who increased their calorie intake at breakfast and reduced their calorie intake throughout the rest of the day saw a reduction in insulin resistance. This led to lower levels of testosterone and a dramatic increase in ovulation frequency.

Previous research suggests that this type of meal pattern could also lower triglyceride levels.


Prof. Jakubowicz studied sixty women suffering from PCOS with a normal body mass index who were randomly assigned to one of two 1800 calorie maintenance diets with identical foods. The first group ate a 983 calorie breakfast, a 645 calorie lunch and a 190 calorie dinner. The second group reversed this with a small breakfast and the larger meal coming in the evening. After 90 days, the researchers tested participants in each group for insulin, glucose, and testosterone levels as well as ovulation and menstruation.

Neither group experienced a change in BMI, however those with a big dinner maintained consistently high levels of insulin and testosterone throughout the study while those in the “big breakfast” group experienced a 56% decrease in insulin resistance and a 50% rise in ovulation rate (indicated by a rise in progesterone).

There is growing evidence that switching how we currently eat can help improve our health. While Americans typically eat a small breakfast, breakfast on the go or no breakfast at all and then eat a significantly larger meal at night (presumably out of abundant hunger), focusing on what used to be called “The most important meal of the day” is becoming the preferred style of eating.

Dr. Jakubowicz also studied the high-calorie breakfast theory on 93 obese women. Those who consumed their largest meal in the morning lost more weight and had lower levels of the hunger hormone ghrelin. They also saw fewer glucose spikes after meals and improved insulin and triglyceride levels.

She says that when “overweight people (get) out of sync with what their bodies need – which is more food early in the day and less at night”, they often gain weight.

Journal Reference:
Effects of caloric intake timing on insulin resistance and hyperandrogenism in lean women with polycystic ovary syndrome Jakubowicz D ,Barnea M ,Wainstein J ,Froy OVolume: 125 / Pages: 423-432

Additional Resources:
Tel Aviv University: Meal Timing Can Significantly Improve Fertility in Women with Polycystic Ovaries Polycystic Ovary Syndrome (PCOS) fact sheet