Fertility Diet

It is well established that diet, exercise, and body weight affect your fertility. The general rule of “all things in moderation” will serve your well! If your weight is too high or too low, your ovulation will be affected. If you exercise too much or too little your ovulatory function will be similarly affected. As far as diet is concerned, recent research from the Nurses’ Health Study offers some important insights. Drs. Chavarro and Willett in their recent book “The Fertility Diet” analyzed data from 18,000 women followed in the Nurses’ Health Study. They looked at dietary and other factors in terms of their effects on fertility. After 8 years of follow up one in six women had difficulty conceiving. They found that diet can affect the risk of ovulatory infertility. There is no information here for men since only women were included in the study. It is also important to know that no other cause of infertility such as tubal blockage was correlated with diet. Other studies back this up. The only clear link between diet and fertility appears to be related to ovulatory function. Ovulation problems are a common cause of infertility being a factor in at least 30% of cases. How do you know if your ovulation is a problem? The 2 most common signs are irregular menstrual cycles or abnormal body weight.

What is an Abnormal Menstrual Cycle?

Your cycle length is the time from your first day of full flow one cycle to the first day of the next cycle. If your cycle length is less than 25 or more than 32 days, it may be a problem. Your doctor can do specific testing such as blood work or ultrasound to confirm an ovulation problem.

What is Abnormal Body Weight?

Many tables of body weight are available. A good general rule for women is to allow 100 pounds for the first 5 feet of height and then 5 additional pounds for each inch. If you are 5’6” tall and of medium frame the formula would yield an ideal body weight of 130 pounds. Allow 10% less for small frame and 10% more if you have a large frame. If your weight is too much above or too much below the ideal your ovulation could be affected.

The Fertility Diet – Low Carb / Slow Carb

Carbohydrates are our source of quick energy. They are rapidly metabolized into sugars which can be used to fuel our immediate energy needs such as in an exercise state or be immediately stored in the form of fats. Unfortunately the last decade can be described as the low fat decade. We were all told that fats are bad for us. Reducing fat intake meant increasing carbohydrate intake for most of us. Unfortunately it is much easier to gain weight from carbs than from fat. It is simply much easier to intake a large amount of calories in the form of carbohydrates. It turns out that not all carbs are created equal. Fast carbs have a high glycemic index and are rapidly metabolized into sugars which cause weight gain and insulin resistance which in turn disturbs normal ovulation. Examples of fast carbs are white rice, white bread, potatoes, cookies, ice cream and sodas. Slow carbs are better for fertility and include brown rice, whole grain pasta and dark bread. Whole grains, vegetables and whole fruit all contain slow carbs.

Good Fats and Bad Fats

Some fats are healthy for you and needed by your body. These are called essential fatty acids. Many prenatal vitamins are fortified with essential fatty acids. Natural foods containing these fats include fish, fish oils, and some nuts.

Most fats found in our food can be divided based on their chemical structure as saturated and unsaturated. During the past decade, we were told that using a lot of saturated fats like butter was not good for your heart. Recently, we discovered that a type of unsaturated fat is also not good for you. This type of fat is called trans fat. These fats are manufactured by a process of hydrogenation of oils to create a product which, when used in cooking, results in a high shelf life for foods. Trans fats are bad for your heart and your fertility. The FDA now requires food labeling which details the amount of trans fats. Some cities such as New York have banned the use of trans fats from all their restaurants. Be careful with the following foods which can be high in trans fats: French fries, stick margarines, shortening, potato chips, doughnuts, and cake.

Tips from the FDA


  • Consider fish. Most fish are lower in saturated fat than meat. Some fish, such as mackerel, sardines, and salmon, contain omega-3 fatty acids, which are being studied to determine if they offer protection against heart disease. Some large fish which live for long periods of time can accumulate mercury. It is therefore suggested that pregnant women limit the intake of such large fish such as Shark, Sword fish, and Albacore tuna to two servings per week. Smaller fish such as Salmon or Tilapia is not a concern. They do not live long enough to accumulate significant quantities of mercury.


Proteins are what’s for dinner. These include the well-known animal proteins such as beef, pork, chicken and fish. In general, these are an important part of your diet and will lead to less weight gain than fats and carbohydrates. Less well known are vegetable proteins which appear to be better for your fertility. These include beans, peas and tofu (soy bean derivative). Peanuts and other nuts are also a good source of vegetable proteins. More protein intake, particularly from a vegetable source, can improve fertility.


Milk has been a source of controversy with some studies showing that it helps fertility and other studies showing a harmful effect. The most recent study show that two servings per day of whole milk or products of whole milk are beneficial. That could be in the form of a glass of milk and a cup of yogurt. In this study whole was better than skim. If your weight is increased, you may need to substitute skim milk since the effect of the weight is itself significant and unfortunately milk is rich in calories.

What About Fish and Mercury?

Large fish eat small fish and live a long time. In the process they accumulate mercury which is not healthy for pregnant women. However, small fish does not and is perfectly safe. Because this is confusing the Food and Drug Administration (FDA) suggests the following guidelines:

  • Do not eat shark, swordfish, king mackerel, or tilefish because they are particularly high in mercury.
  • Eat up to 12 ounces (two average meals) per week of a variety of fish and shellfish that are lower in mercury. This would include shrimp, crab, scallops, oysters, cod, pollock, tilapia, fresh water trout, salmon and canned light tuna.
  • If you choose albacore white tuna instead of canned light tuna, eat only up to 6 ounces (one average meal) per week.

Fish contains proteins and health omega 3 fats. You don’t have to cut it out of your diet. Most of the commonly available fish are the safe ones which you can have 2 servings per week of.

Body Weight

There is no question that weight is a major factor affecting fertility. Most commonly the issue is high body weight, but in some cases low body weight can be a problem. There are many diets which can be of help. These range from the Atkins high protein diet to Weight Watchers or Jenny Craig. It is important to find some system that you believe in and to set modest goals such as a 10% initial weight loss. Remember that the first week of any dietary change is the hardest. After the first week, you will be more acclimated to this change and progress can begin. Too many carbs are frequently the problem with the modern convenience food diet. Remember, it is easier to gain weight from too many carbs than any other single category.


Exercise was also shown to boost fertility. A reasonable plan is to set aside 30 minutes every day for exercise. This can be aerobic such as walking fast or running or muscle building such as working with weights. A mixture of both forms is probably the best. Anything is probably better than nothing. Remember that the longest journey begins with one step. Exercise has many other benefits such as improving heart health and longevity.