The guidelines also establish ranges (called acceptable macronutrient distribution ranges or AMDR) for fat, carbohydrates and protein, instead of exact percentages of calories or numbers of grams. The report maintains that since all three categories serve as sources of energy, they can, to some extent, substitute for one another in providing calories.

A healthy vegetarian diet falls within the guidelines offered by the USDA. However, meat, fish and poultry are major sources of iron, zinc and B vitamins, so pay special attention to these nutrients. Vegans (those who eat only plant-based food) may want to consider vitamin and mineral supplements; make sure you consume sufficient quantities of protein, vitamin B12, vitamin D and calcium. You can obtain what you need from non-animal sources. For instance:

As women, many of us are prone to neglecting our own dietary needs. You may feel you’re too busy to eat right, used to putting the needs of your family first, or trying to adhere to an extreme diet that leaves you short on vital nutrients and feeling cranky, hungry, and low on energy. Women’s specific needs are often neglected by dietary research, too. Studies tend to rely on male subjects whose hormone levels are more stable and predictable, thus sometimes making the results irrelevant or even misleading to women’s needs. All this can add up to serious shortfalls in your daily nutrition.

A year later, a second Harvard study added to the concern. The Physicians' Health Study of 20,885 men did not evaluate diet per se, but it did measure the blood levels of ALA in 120 men who developed prostate cancer and compared them with the levels in 120 men who remained free of the disease. Men with moderately high ALA blood levels were 3.4 times more likely to develop prostate cancer than men with the lowest levels; curiously, though, men with the very highest levels were only 2 times more likely to get the disease.

You should eat a healthful, well-balanced diet during pregnancy. However, you should avoid certain foods, including raw or undercooked fish, poultry and meat; raw or partially cooked eggs or foods containing raw eggs; unpasteurized juices; raw sprouts; unpasteurized milk products; and some soft cheeses (cream cheese is OK). Avoid deli meats and frankfurters unless they have been reheated to steaming hot before eating. To prevent food-borne illnesses, take the following precautions: