I was fortunate enough to be asked by a media company to work with a journalist and write a column on Fertility and diet. This was fascinating for me as it meant I spent some time reading the research on this area and brushing up my knowledge. The article is at  the end of this post.

There has been some good research showing:

• There is a U-shaped relationship between weight and fertility, with lower fertility rates in obese and underweight women, so you have the best chances of concieving when you are a healthy BMI.
• Caffeine should be restricted to <300mg/d (1-2 cups tea/coffee). More than this is linked to an increased risk of miscarriage and poor fetal growth. Caffiene has a prolonged half life meaning it hangs around in the body so you really want to cut down the caffeine before you become pregnant. 
• A large piece of research calls the Nurses Health study followed 17,000 plus women who were trying to conceive over a period of 8 yrs. The study showed that healthy eating is key. Women eating less trans fats, more monounsaturated fats (heart healthy fats such as olives and avocardo), more plant protein, high fat dairy products, high fibre, low glycaemic index carboydrates and more iron that comes from plants had higher fertility rates.
•  There is some research to suggest over exercising and infertility may be linked. Although it is not proven that it is the exercise that causes the infertility, it makes sense as over exercising can stress the body and lead to being underweight, which are things we know affect fertility.