Fertility diet basics

The science

With so many different diets on offer now, it can be confusing to know which foods are best. Our approach is based on the diet advocated by the researchers behind the Nurses’ Health Study. This study examined the effects of diet and other lifestyle changes on fertility among 20,000 female nurses, and was a landmark long term study led by professors and clinicians at Harvard Medical school. We have adapted it slightly so it is translatable to the UK food industry and we have also included additional advice from Public Health England and the NHS.

This approach, based on science, doesn’t focus on a single miracle food or dietary demon. Instead it offers a balance of healthy choices. It is built from these key building blocks: more fruits and vegetables, good fats, good sources of carbohydrates, healthy protein and smart drink choices. The below picture shows what healthy eating for fertility looks like.

The study analysed the diet, and found ten simple changes that offer a boost in fertility for women. Women in the study who followed three or four of the recommendations suggested in the Fertility Diet were 66% less likely to have problems conceiving than women who didn’t. In this programme we’ll guide you through all ten of these changes, plus strategies to improve your relationship to food.

The first important step is understanding and managing your Body Mass Index (BMI). BMI is a measure that combines height and weight into a single number and is a good indicator of total body fat. Women who start pregnancy with a normal BMI, compared to overweight or obese women, have better maternal and infant outcomes. Overweight and obese women also have a higher risk of their children being overweight or obese.

Being severely underweight or overweight can interrupt normal menstrual cycles, impact ovulation or stop it all together.  It’s therefore important to maintain a healthy lifestyle and BMI for your fertility health.

Weight isn’t just an issue for women. Research also indicates that overweight men aren’t as fertile as their healthy weight counterparts, with excess weight lowering sperm production.

So what is a normal BMI? Here are the NHS guidelines:

Low (underweight)NormalHigh
Below 18.518.5 and 24.925 and 29.9 (overweight)

+30 (obese)

The Nurses’ Study found that infertility was least common among women with a BMI between 20 and 24, with an ideal BMI around 21. Of course women with higher and lower BMIs than this get pregnant all the time without delay or any medical help. So if you aren’t within this range, don’t worry. Working to move your BMI to that range by gaining or losing some weight could have a positive impact.

If you’re overweight, losing 5 to 10% of your weight is often enough to improve ovulation. Even when that loss doesn’t get them to the healthy weight range. Among all overweight women, reducing your weight by 5-10% improves your health across the board. A major trial called the Diabetes Prevention Program, included more than 3,200 people who were at risk of developing type 2 diabetes. Those who lost just 7 percent of their weight and exercised about thirty minutes a day cut their risk of developing diabetes by nearly 60%. For women who have polycystic ovary syndrome (PCOS) , this amount of weight loss can not only help to restore ovulation and menstruation but can also clear the skin and curb excess hair growth.

Your task/change for the week

Understand what your BMI is – is it low, medium or high?

If your BMI is normal:

  • It’s still important to maintain a healthy lifestyle – this includes focus on eating a healthy balanced diet, reducing alcohol intake and exercising regularly to maintain your BMI while you are trying to conceive.

If your BMI is high (more than 30):

  • Start by reducing your calorie intake by 500 calories per day
  • Here are some ideas for easy foods to avoid:
    • Pret croissant – 291 calories
    • Pret chocolate chunk cookie – 370 calories
    • Pret macaroni cheese – 586 calories
    • Starbucks Caramel Frappuccino – 420 calories
    • Starbucks Cafe Mocha – 290 calories
    • Plain bagel (4-inch diameter) – 257 calories
    • Chocolate ice cream (1 cup) – 286 calories
    • Starbucks cafe mocha with whipped cream (12 ounces) – 310 calories
    • Pints of 5% beer – 430 calories
    • Glass of wine (250mls) – 203 calories
    • Haribo (100g starmix) – 580 calories
    • Snickers bar – 245 calories
    • Jacket potato with butter and cheese – 600
    • A glass of fruit juice – 136
    • Sainsbury’s Chewy Granola Slices – 368 calories
    • Walkers cheese and onion – 169 calories
  • Exercise regularly – 3 times a week or at least 150 minutes per week

If you’re BMI is low (below 18.5)

  • To gain weight you can do this gradually by making some healthy food swaps. Try not to focus on increasing your intake of unhealthy foods such as, sugar, chocolate and cakes but instead focus on the pyramid above and try to increase your portion sizes. If you are worried about your weight speak to a GP or a registered dietitian as they will be able to provide you with more detailed advice. You can also get support from Adia’s nutritionist.
  • Here are some ideas for how to increase your intake:
    • Plan your meals to contain starch/carbohydrates such as wholegrain pasta or rice, potatoes or bread
    • Eat a variety of fruit and vegetables and aim for at least 5 a day
    • Drink plenty of fluids throughout the day
    • Smoothies are a great healthy way to increase your calorie intake – especially if they are homemade, then you know exactly what you’ve put them
    • If you consume dairy products look at changing to the full-fat version.