Fertile Weight: Why Weight Matters and How to Achieve a Healthy Weight for Optimal Fertility

There are so many different ways that nutrition and lifestyle can affect your fertility, but perhaps the most basic way is via weight. Weight is something that is often difficult to talk about and something that physicians and other healthcare providers can be reluctant to bring up with their patients, but it can play a very significant role in fertility.  Being underweight or overweight can negatively impact fertility and have higher rates of miscarriage. Here's how to determine if your weight may be affecting your fertility:

1. Calculate your Body Mass Index (BMI). Use this link, and simply enter your height and weight.
2. Use the following chart to determine which category you fall into according to your BMI:

This chart shows the normal range of BMI for overall health. Things are a little bit different for fertility. Women should aim for a BMI of 20-24.9 for optimal fertility. Women with BMI between 18.5 and 20 may still be considered normal weight, but when body fat tends to be lower it can be harder to conceive.

If you are overweight, losing even 5% of your body weight can significantly improve fertility. In a 200-pound woman, this means a weight loss of only 10 pounds to have a beneficial effect. Weight loss can help restore normal ovulatory cycles in overweight women with or without PCOS and can improve hormone balance. Conversely, if you are underweight, gaining weight to get your BMI over 20 can also support regular ovulation and your ability to maintain a pregnancy.

BMI doesn't tell us the whole picture since it's only based on height and weight and doesn't tell us about body composition. Another important factor in fertility is body fat percentage. Women typically need a minimum of 20% body fat in order to have regular menstrual cycles in which they ovulate. A body fat up to 31% would be considered normal, with anything above 31% considered excess body fat according to the American Council on Exercise. Did you know that we can measure your body fat percentage at Pulling Down the Moon using something called Bioelectrical Impedance Analysis (BIA)? We use BIA as part of our FirstLine Therapy for Fertility program to track changes in body fat percentage, and we also use it to determine whether or not women have a healthy amount of body fat for fertility.

If you are underweight, making sure you eat adequate protein and healthy fats are priorities. Incorporating a high calorie shake can also be helpful. Check out these great shake recipes. If you're overweight, check out our FirstLine Therapy for Fertility (FLTF) program with a new group starting March 21st.  FLTF is a high protein, low glycemic modified Mediterranean style eating plan designed to help you lose weight, decrease inflammation, and improve your fertility. FLTF is a very effective program. Check out this progress report from women who've done the program, and we hope to see you soon!

By Margaret Wertheim, MS, RD, LDN

Categories: Blog