UAB Medicine News


Do Restrictive Diets and Eating Disorders Affect Fertility?

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For pregnant women, nutrition has a huge impact on the health of the unborn baby and how you feel during pregnancy. But physicians and patients also are interested in how diet can affect the reproductive system of women who are trying to get pregnant or want to have a baby in the future.

UAB Medicine OB/GYN Deidre Gunn, MD, weighs in on this topic and explains how restrictive diets and eating disorders may affect your fertility.

Extreme Diets

Each year brings new and trendy diets that offer women hope of losing weight and getting their bodies into shape. To jump-start weight loss, many of these diets are based on restrictions, such as not eating carbs or skipping some meals. By cutting out certain foods, however, you may be depriving yourself of what your body needs to support a growing baby.

“There are dozens of diets out there that can help you lose a bunch of weight in the short term, but ultimately you want to do this in a healthy way and also be able to keep the weight off,” says Dr. Gunn, who specializes in obstetrics, gynecology, reproductive endocrinology, and infertility. “Restrictive diets like a keto diet or intermittent fasting are hard to maintain long-term, and they’re also not ideal for fertility, because your body doesn’t get the right balance of nutrients it needs for reproduction.”

Eating Disorders

Restrictive diets are one thing, but eating disorders take restrictions to a whole new level. Eating disorders affect every aspect of a woman’s health, especially her fertility and the regularity of her menstrual cycle. Dr. Gunn says this is because the pituitary gland in the brain is very sensitive to extreme calorie deprivation and excessive exercise.

“Many women who have eating disorders or who exercise too much will begin having irregular periods or even stop having periods altogether,” Dr. Gunn says. “When that happens, it usually means the ovaries aren’t releasing an egg every month. Ovulation essentially stops, because the body simply doesn’t have the calories to support a potential pregnancy.”

Healthy Weight Before Pregnancy

Dr. Gunn stresses that getting to a healthy body mass index (BMI) is very important, not only for a woman’s general health but also to lower the risks of dangerous complications during pregnancy. Obesity (defined as a BMI greater than 18.5) makes pregnancy much riskier, which is why it’s a good idea to address your BMI before trying to get pregnant.

But what many women don’t realize is that both ends of the weight spectrum can be bad for fertility. Women who are underweight – with a BMI less than 18.5 – are at the opposite extreme and may have irregular menstrual cycles and ovulation. A woman with a BMI that is too low may not release an egg every month for ovulation and therefore have a much harder time getting pregnant.

“If you’re thinking about getting pregnant in the next year or so, now is the time to start thinking about getting healthy and setting yourself up to have the safest pregnancy possible – for you and your future baby,” Dr. Gunn says.

Support Fertility with Nutrition

One of the best ways to support your fertility is to know your BMI number, work to achieve a number between 18.5 and 25, and then maintain that number with a balanced diet.

“You want to focus on eating whole grains rather than processed foods, eating lots of fruits and vegetables, eliminating sodas and sugary beverages like juice and sweet tea, and choosing lean meats like fish and poultry over red meat,” Dr. Gunn says. “And don’t forget a prenatal vitamin, which you should actually start taking before you get pregnant. That way, your body is already getting all the important nutrients needed for early fetal development when you do get pregnant.”

Advice for Women

Extreme dieting has been the norm for many women for much of their lives, with far too many women trying “miracle diets” and quick fixes to lose pounds fast. Meanwhile, the National Association of Anorexia Nervosa and Associated Disorders estimates that at least 30 million people in the U.S. of all ages and genders suffer from an eating disorder. If you don’t struggle with these issues yourself, chances are that someone you love is facing them right now.

Fortunately, there is help available for women who want to get pregnant but who are battling an eating disorder or extreme dieting habits. The first step is to talk to your doctor or OB/GYN. However, treating an eating disorder may require the help of a specialist or dietitian who can help you choose the best foods and adjust your portion sizes.

The UAB Weight Loss Medicine Clinic works with patients to develop a personalized program for weight loss, to make sure they do it in a healthy way. A goal of this program is to teach people how to choose healthy foods low in energy density such as fruits, vegetables, and other sources of fiber rather than foods that with more fat and calories per gram. For patients who need to lose 50 pounds or more, UAB Weight Loss Medicine offers OPTIFAST meal replacement, a safe and effective program that has proven to be consistently successful.

“Patients usually need a combination of different support services to help with their eating disorders, including medical, nutritional, and mental health support,” Dr. Gunn says. “It’s important to remember that you’re not alone and there are so many resources to help you. So, please take that first step and ask!”

Click here to learn about Women & Infants Services at UAB Medicine, or visit the UAB Weight Loss Medicine Clinic.