According to the World Health Organization, infertility affects between 48 million couples and 186 million individuals globally.  Infertility affects both men and women and is defined as not being able to conceive after 12 months or more of regular unprotected sex.
Even though there is anecdotal evidence of the benefits of keto on fertility from clinical practitioners and their patients, there are few studies examining the effects of the ketogenic diet on fertility. The majority of existing studies focus on the diet’s effect on polycystic ovary syndrome (PCOS). We were not able to find studies on how the ketogenic diet affects male fertility.
Infertility and Polycystic Ovary Syndrome
PCOS is a common endocrine disorder in which the ovaries produce an abnormal amount of male sex hormones, which are usually only present in women in small amounts. It is a very complex disorder with many clinical manifestations and symptoms including difficulty conceiving. Women with PCOS also have an increased risk for type 2 diabetes mellitus, cerebrovascular and cardiovascular disease, anxiety and depression, and a substantially increased risk for complications during pregnancy and birth if they succeed in getting pregnant. 
It isn’t known what causes PCOS, but there might be a genetic component, as it’s common for several women within the same family to have PCOS. When women with PCOS wish to get pregnant, they are often given medications to stimulate ovulation, and if unsuccessful, fertility treatments such as in-vitro fertilization (IVF) are the next options.
The Connection Between Being Overweight or Obese and Infertility