Are you struggling to get pregnant because of polycystic ovaries (PCOS)? Here’s some good news: a new study suggests that women with PCOS may face fewer fertility issues if they eat a good breakfast and a lighter dinner.

PCOS and fertility – the link

PCOS affects fertility by creating a state of resistance to insulin, pushing the ovaries to produce an excess of testosterone, the male sex hormones. Too much testosterone meddles with ovulation as it interferes with the equilibrium of the female sex hormones – suboptimal ovulation would make it harder for you to get pregnant.

Study details

The 12-week study involved 60 women diagnosed with PCOS – they were all slim with a BMI below 23kg/m2. The women, aged 25 to 30, were asked to adhere to an 1800kcal diet and were randomly assigned to one of two groups:

  • The breakfast group: The women consumed a big breakfast of 980kcal and a small dinner of 190kcal.
  • The dinner group: The women ate a small breakfast of 190kcal and a larger dinner of 980kcal.

All the participants were advised to have a 640kcal lunch. They were also asked to record everything they ate in a food diary.

Study findings

The scientists discovered that ovulation improved among women who ate a big breakfast and a small dinner. Although none of them ovulated in the first month of the study, 50% of the breakfast group had ovulated by the end of the study compared to only 20% of the dinner group. And 5 women in the breakfast group ovulated twice; none did in the dinner group.

The women in the breakfast group showed improvement in insulin sensitivity – after 90 days, their fasting blood glucose levels dropped by a significant 8% and their insulin levels decreased by 53%. No such changes were observed in the dinner group.

While there were no changes in sex hormone levels among women in the dinner group, those in the breakfast group had a 50% decrease in testosterone levels and a 105% increase in SHBG (sex hormone-binding globulin). Higher SHBG levels can ameliorate some PCOS symptoms such as acne and excess hair growth.

“The research clearly demonstrates that indeed the amount of calories we consume daily is very important, but the timing as to when we consume them is even more important,” said study author Oren Froy, a nutrition and health specialist.

So does that mean you should eat almost 1000kcal for breakfast?

That’s really up to you but 1000kcal is a lot to eat in one sitting unless you’re having a few doughnuts and a sugar-laden milkshake first thing in the morning. However, not only would that be plain unhealthy, but consuming a diet rich in refined foods can actually promote accumulation of body fat – this would worsen insulin resistance. But if you plan to try a 980kcal breakfast, make sure to reduce your dinner, otherwise you may gain weight – this could adversely impact your fertility.

Keep in mind that not all women with PCOS have the same glucose tolerance in the morning. Some women find that consuming only one slice of bread shortly after waking up can throw their glucose levels off the charts. A dietitian could work with you to create a safer, more effective diet that suits your personal tastes and dietary habits.

In the meantime, you could have 3 main meals (a light dinner) and 2 snacks. Ideally, your dinner should be composed of a lean protein source like grilled fish and some salad or veggies. You can also check out this article for a list of foods that can improve your fertility.

What if you’ve got some extra kilos?

Remember that only losing 5% of your weight can considerably ameliorate your PCOS symptoms and chances to conceive.


    Jakubowicz et al (2013) Effects of caloric intake timing on insulin resistance and hyperandrogenism in lean women with polycystic ovary syndrome. Clin Sci (Lond). 125(9):423-432.