What Is the Fertility Diet?

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The fertility diet is designed to help you get pregnant by making several changes in your diet and activity. These changes emphasize consuming foods, such as plant protein and full-fat dairy products, that the authors believe can boost fertility.

The diet is rooted in science: the Harvard Medical School physicians who developed it delved deeply into a long-term study involving tens of thousands of women to see what those women ate and how often they got pregnant. Although the data doesn't prove that following the fertility diet will help you conceive, nutritional experts say some aspects of the program definitely may increase your chances of getting pregnant.

What Experts Say

The fertility diet provides recommendations for women trying to increase their odds of pregnancy. The advice includes avoiding trans fat, eating high-fiber foods, and incorporating more vegetarian meals. Experts agree these tips may be helpful for women trying to become pregnant.

Chrissy Carroll, RD, MPH

Background

Diet and exercise can have profound effects on your health and well-being. Various clinicians, including authors of The Fertility Diet, theorized that diet and exercise also could influence fertility.

Using data from the second round of the massive Nurses' Health Study, which began in 1989, author Walter Willett, M.D., Dr.PH., identified 18,555 women who had said they wanted to get pregnant, and then followed study data to see whether they were able to conceive and how long it took them. Around 3,400 of those women had trouble getting pregnant, and Willett and his co-author, Jorge Chavarro, M.D., Sc.D., used data they provided to see what dietary and exercise factors appeared to be most important to fertility.

They published their results in 2007 in The Fertility Diet, which attempts to convert the research into tactics women can implement to get pregnant. The diet and exercise tactics are aimed specifically at ovulatory infertility, which is the type of infertility you have if your ovaries aren't producing mature eggs during each menstrual cycle. This type of infertility affects around one-quarter of couples who have trouble getting pregnant.

Many of the recommendations will sound familiar to people already well-versed in healthy eating, and the authors speculate that some of the strategies might help to improve fertility in men, as well as in women.

The diet fertility diet isn't specifically a weight loss diet. However, the authors' research found that women who had body mass indexes between 20 to 24—the range that's considered normal body weight—were least likely to have infertility. In addition, the authors note that overweight women who are having trouble ovulating may be able to improve their odds by losing 5% to 10% of their total body weight. Therefore, The Fertility Diet includes tips for losing a modest amount of weight.

How It Works

Drs. Willett and Chavarro believe there are 11 key diet and exercise changes women can make to improve their chances of getting pregnant. The changes emphasize switching from certain foods they believe might impede conception to foods that could help conception. These changes include:

  1. Avoid trans fats, which have been banned in the U.S. due to their adverse health effects.
  2. Use more unsaturated vegetable oils, such as olive oil and canola oil.
  3. Eat more vegetable protein, like beans and nuts, and less animal protein.
  4. Choose whole grains and other sources of carbohydrates that have "lower, slower effects on blood sugar and insulin" rather than "highly refined carbohydrates that quickly boost blood sugar and insulin."
  5. Consume milk fat every day in the form of a glass of whole milk, a small dish of ice cream, or a cup of full-fat yogurt, and "temporarily trade in skim milk and low- or no-fat dairy products like cottage cheese and frozen yogurt for their full-fat cousins."
  6. Take a multivitamin with folic acid—critical to fetal development—and other B vitamins.
  7. Get plenty of iron from fruits, vegetables, beans, and supplements, but avoid red meat (which is another source of iron).
  8. Avoid sugary sodas and other sugar-laden drinks, and drink coffee, tea, and alcoholic beverages in moderation. Instead, drink water.
  9. Aim for a healthy weight. If you are overweight, losing between 5% and 10% of your weight can jump-start ovulation, according to the research.
  10. Start a daily exercise plan, or if you already exercise, work out harder. Still, you shouldn't overdo it, especially if you're already thin, since too much exercise can work against conception.
  11. If you smoke, try to quit, since research has shown that smoking has a significant adverse impact on fertility.

What to Eat

Compliant Foods

  • Unsaturated vegetable oils, such as olive oil and canola oil

  • Vegetable protein from beans and nuts

  • Whole grains

  • Whole milk, ice cream, or full-fat yogurt

  • Iron-rich fruits, vegetables, and beans

Non-Compliant Foods

  • Trans fats

  • Animal protein, especially red meat

  • Highly refined grain products

  • Sugar-sweetened beverages

  • Coffee and tea (only drink in moderation)

  • Alcohol (only drink in moderation)

Unsaturated Vegetable Oil

The diet recommends replacing saturated fat with monounsaturated fat and polyunsaturated fat. These types of fats are considered healthy. Monounsaturated fats are found in olive oil, canola oil, avocados, and nuts such as cashews and almonds. Seeds, such as sesame and pumpkin seeds, also are good sources of monounsaturated fat.

Polyunsaturated fat, meanwhile, is found in fatty, cold water fish such as sardines, salmon, and tuna. However, since fish can be a source of mercury (which is dangerous to a developing child), the fertility diet recommends getting polyunsaturated fats from plant sources, such as flaxseeds, walnuts, and canola oil. Soybeans, sunflower, and safflower oil also can provide polyunsaturated fat.

Vegetable Protein

The research that led to The Fertility Diet found that women who had the highest intake of animal protein were 39% more likely to experience ovulatory infertility than those with the lowest intake of animal protein. In fact, adding one serving per day of red meat, chicken, or turkey predicted nearly a one-third increase in the risk of ovulatory infertility.

However, the reverse was true when the researchers looked at plant protein: women who consumed a lot of plant protein were much less likely to have ovulatory infertility. Therefore, the authors concluded that eating more protein from plants and less from animals could help with infertility and improve your chances of conceiving.

Whole Grains

The total amount of carbohydrates in the diet wasn't connected with ovulatory infertility—women who consumed the lowest level of carbohydrates were just as likely as those who consumed the highest level of carbohydrates to have trouble conceiving, according to Drs. Willett and Chavarro. However, the type of carbohydrate sources did appear to play a role.

Specifically, women who consumed lots of carbohydrates with a high glycemic load—basically, foods that tended to be digested and turn into sugar quickly—were more likely to have infertility than women who consumed carbohydrates with a lower glycemic load (the type that contain plenty of fiber and so take longer for the body to break down).

The diet doesn't require you to follow the glycemic index. Instead, it simply recommends you switch to whole grains for bread and pasta, consume more beans, and eat plenty of vegetables and whole fruit. You also should switch out your soda for water.

Whole Milk Products

Drs. Willett and Chavarro thought they might find connections between lots of dairy and infertility as they combed through the data from the nurses' study. However, they didn't find that at all. Instead, they found an association between low-fat dairy products and infertility: the more low-fat dairy products in a woman's diet, the more likely she was to have had trouble getting pregnant. Conversely, the more full-fat dairy products in a woman's diet, the less likely she was to have had problems getting pregnant.

The "most potent fertility food" was whole milk, followed by ice cream and full-fat yogurt. Therefore, The Fertility Diet recommends that every woman trying to get pregnant consume one serving of full-fat milk, ice cream, or yogurt per day. This doesn't mean binging on Ben & Jerry's, though, since the serving size envisioned here is about half a cup.

Iron-Rich Fruits, Vegetables, and Beans

Women who are trying to get pregnant seem to have better luck when they're consuming between 40 and 80mg of iron per day, which is two to four times higher than the general iron intake recommendations for women, The Fertility Diet reports.

To get that much iron, the diet recommends focusing on iron-rich plant-based foods. For example, apricots, dark leafy greens such as spinach, asparagus, and coconut all are high in iron, as are many beans and some nuts. However, you may also want to consider talking to your doctor about taking an iron supplement; in fact, many prenatal vitamins contain a hefty dose of iron.

Recommended Timing

When you're following the fertility diet, you don't need to time your meals or your snacks. The diet only calls for focusing on specific foods, not for eating at specific times of day, or for rotating foods.

Still, the authors do recommend that those who want to lose weight on the fertility diet eat a good breakfast—one that includes an egg, yogurt, or oatmeal, with whole wheat toast on the side—within a couple of hours of awakening for the day. This helps to check the boxes for plant protein, whole grains, and whole milk. The authors also recommend that women who are trying to lose weight not eat anything after dinner.

Resources and Tips

The Fertility Diet includes a week's worth of meal plans and 15 recipes for dishes that fit into the diet, including Red Lentil, Toasted Almond, and Ginger Soup, Broccoli and White Bean Gratin, and Orange-Glazed Salmon.

Beyond that, those following the diet are urged to eat healthful meals that follow the tenets of the diet. Those who are at their ideal weight should consume around 2,000 calories per day, while those who want to shed some weight should consume around 1,750 calories per day.

When it comes to exercise, if you're following the fertility diet and you're not already active, you should start an exercise plan that includes some vigorous workouts. "Working your muscles is good—not bad—for ovulation and conception. It's an integral part of losing or controlling weight and keeping blood sugar and insulin in check," the authors write. Vigorous activities may include competitive sports, exercise such as jogging, fast bicycling, and step aerobics, or even carrying groceries upstairs.

Modifications

Since the fertility diet is flexible—it only recommends specific types of foods, such as plant proteins, as opposed to requiring specific foods—it's easy to modify. For example, if you follow the gluten-free diet, you easily can avoid gluten-containing foods as long as you make sure to get enough fiber and plant protein from gluten-free foods. If you've been diagnosed with a food allergy, such as a tree nut allergy, you simply can skip any tree nuts while following the basic tenets of the fertility diet.

The diet does pose a bit of a dilemma for women who have an allergy to milk, those who are lactose intolerant, or those who just don't like milk. However, the authors say you shouldn't stress over not being able to have full-fat milk products on the diet, since there are many other tactics you can follow to improve your odds of getting pregnant.

Pros and Cons

Pros

  • Diet is generally healthy

  • Plant-based foods are emphasized

  • Avoids high-sugar foods

  • Steers clear of trans fats

Cons

  • Diet requires calorie counting

  • Emphasis on full-fat milk products

  • May require more meal prep

  • Could include too much iron

Pros

Diet Is Generally Healthy

The diet is designed for women who are trying to get pregnant, but many of its recommendations—eat lots of vegetables, avoid sugary foods, and get plenty of fiber—apply to everyone, not just women who are trying to conceive. Drs. Willett and Chavarro are careful to note cases in which their recommendations for resolving infertility may not match recommendations for an overall healthy diet.

Plant-Based Foods Are Emphasized

The diet recommends getting less animal protein and more plant protein. Doing so will boost your fiber intake (high protein plant foods, such as beans, also are high in fiber), and will improve your intake of various vitamins and minerals. It also will reduce your intake of saturated fat, which may help your overall health.

Avoids High-Sugar Foods

Rapidly digested carbohydrates—the kind found in soft drinks, cakes and other sweets, chips, white bread, and beer—is bad for fertility, according to The Fertility Diet. They're also bad for your heart and could increase your risk for diabetes and other conditions that are influenced by diet. Swapping out these foods for options that are higher in fiber is a good idea generally.

Steers Clear of Trans Fats

There's literally nothing good to be said about trans fats, which have been widely linked to heart disease. Since the publication of The Fertility Diet, the FDA banned artificial trans fats, so avoiding them should be simple if you live in the United States.

Cons

Diet Requires Calorie Counting

If you're trying to lose weight while you're following the fertility diet program, you'll need to count calories to ensure you're not getting too few or too many. The "sweet spot" is around 1,750 calories per day. If you currently sit at a normal weight, you also may need to count calories to make sure you don't gain or lose while you're following the diet plan.

Emphasis on Full-Fat Milk Products

The authors of The Fertility Diet firmly believe that full-fat dairy products can help improve ovarian function and therefore help infertility—that's what their research shows. However, they also say that long-term, eating a lot of full-fat dairy may not be the healthiest approach for your body. In addition, adding full-fat dairy may mean you need to subtract some other food in order to keep your calorie count (and your waistline) from expanding.

May Require More Meal Prep

Eating a healthy diet takes more time than just grabbing a burger and fries at your local drive-through window. If you follow the diet as outlined, you'll wind up spending more time on meal preparation, since you'll need to cook healthy ingredients from scratch.

Could Include Too Much Iron

Women who are in their childbearing years need far more iron than men, as do pregnant women. However, it's possible to get too much iron, and the recommendations for iron intake in the fertility diet plan could overdo the iron. Before you take more iron than is included in a recommended prenatal vitamin, make sure to talk to your doctor.

How It Compares

The fertility diet compares quite well with the overall elements of a healthy diet. Putting aside the issue of full-fat dairy, the diet's recommendations for fruit, vegetables, plant protein, and whole grains parallel what most experts would consider to be a near-ideal eating plan.

The 2019 U.S. News and World Report Best Diets ranks the Fertility Diet number 11 in Best Diets Overall and gives it an overall score of 3.5/5.

USDA Recommendations

The U.S. Department of Agriculture's MyPlate nutritional guidelines closely track the recommendations in the fertility diet, with a focus on whole grains, fruits, vegetables, and lean protein. The only major difference is in the dairy section: MyPlate recommends skim milk and non-fat or low-fat yogurt, while the fertility diet calls specifically for full-fat versions of dairy products.

Similar Diets

Flexitarian Diet

"Flexitarian" is a combination of "flexible" and "vegetarian," and the flexitarian diet can be both. Like the fertility diet, the flexitarian diet relies heavily on plant-based protein and avoids highly refined carbohydrates and added sugar. However, it allows people following the diet plan to consume meat, refined carbs, and sugar in moderation.

Mediterranean Diet

The Mediterranean diet emphasizes lots of vegetables and whole grains—foods that don't spike your blood sugar. That makes it similar to the fertility diet. Still, while the Mediterranean diet is heavily plant-based, it also allows for plenty of fish and poultry in moderation. Those foods are not encouraged on the fertility diet.

A Word from Verywell

Although you can lose weight on the fertility diet, that's not its main purpose; the diet intended specifically to help women who are having trouble conceiving because they aren't ovulating. Nonetheless, it's a generally healthy diet. Coupled with recommendations on physical activity, the diet should improve your overall well-being, and it might help you get pregnant.

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Article Sources

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  • Chavarro, Jorge, et al. The Fertility Diet. McGraw-Hill, 2009.