Why Women Need Fat to Be Healthy

It's a common misconception-oh, don't eat that, it has a lot of fat in it. Fitness fiends and non-fitness fiends alike assume women should never have any fat at all, but authors William D. Lassek, M.D. and Steven J. C. Gaulin, Ph.D. will have to disagree. In their book, Why Women Need Fat: How 'Healthy' Food Makes Us Gain Excess Weight and the surprising solution to Losing It Forever, the two discuss just that--why women need fat, plus the kinds of fat they should be consuming daily.

"The idea that all fat is bad and unhealthy seems to be widespread, whether it comes in our diets or is part of our bodies. One reason for this is that the label of every food product we buy starts off by listing its (usually high) percentage of our daily 'allowance' of fat," the authors say. "And most women, even many who are quite thin, would like to have less fat on their bodies. But in both cases-bodies and food-some kinds of fat are beneficial for health, while others can be unhealthy."

We caught up with Lassek and Gaulin to reveal more fat facts you need to know, so when you start consuming this fat that they speak of, you're doing it the right way.

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SHAPE: Tell us about fat.
LASSEK AND GAULIN (LG): Fat comes in three forms: saturated, monounsaturated, and polyunsaturated. Most of us have heard that saturated fat is very unhealthy, but many researchers are now questioning whether this is true. Monounsaturated fat, like that in olive and canola oil, is linked with better health. Polyunsaturated fats are the only type of fat that we have to get from our diet . These come in two forms, omega-3 and omega-6, and both are important.

While almost everyone agrees that having plenty of omega-3 fats is beneficial, there is growing evidence that too much omega-6 fat may not be good for weight or health. Different types of dietary fat are connected to different types of body fat . Higher levels of omega-6 are linked to higher levels of unhealthy belly fat, while higher omega-3 is linked to the healthier fat in the legs and hips. so when it comes to fat, we need to "do nuance."

SHAPE: So why do women need fat?
LG: While women are able to undertake any kind of work or play they want to, their bodies have been designed by evolution to be very, very good at having children, whether they choose to or not. All of these children are very unique in having brains that are seven times larger than would be expected for other animals our size. This means that women's bodies have to be able to provide the building blocks for these large brains during their pregnancies and while nursing their children-building blocks that are stored in women's fat.

The most critical brain-building block is the omega-3 fat called DHA , which makes up about 10 percent of our brain not counting water. Since our bodies cannot make omega-3 fat, it has to come from our diet. During pregnancy and while nursing, most of this DHA comes from a woman's stored body fat, and this is why women need to have so much more body fat than other animals (about 38 pounds of fat in a woman weighing 120 pounds). So women have an undeniable need for fat in their bodies and fat in their diets.

SHAPE: How much fat should we get daily?
LG: It's not the amount of fat that, but the kind of fat. Our bodies can make saturated and monounsaturated fat out of sugar or starch, so we don't really have a minimum need for these as long as we have plenty of carbs. However, our bodies cannot make the polyunsaturated fats that we need for our brains, so these have to come from our diet. These polyunsaturated fats are considered "essential." Both types of essential fats-omega-3 and omega-6-are needed; they play a number of important roles, especially in the cells in our brains.

SHAPE: In our fat consumption, do age and life stage play a role?
LG: Having plenty of omega-3 fat is important for every life stage. For women who may want to have children in the future, a diet high in omega-3 is especially important in order to build up the DHA content of their body fat, because that fat is where most of the DHA will come from when they are pregnant and nursing.

Since there is some evidence that omega-3 helps muscles work better, more active women will likely benefit from having more in their diets. For older women, omega-3 is important for good health and to reduce the risk of Alzheimer's disease . For infants and children, getting enough omega-3 fat is especially important, since their bodies and brains are actively growing and developing.

SHAPE: Where can we find "good fats?"
LG: Good fats are fats high in omega-3. DHA and EPA are the most important and active forms of omega-3, and the most abundant source for both is fish and seafood, especially oily fish. Just three ounces of wild-caught Atlantic salmon has 948 milligrams of DHA and 273 milligrams of EPA. The same amount of canned tuna fish has 190 milligrams of DHA and 40 of EPA, and shrimp have a bit less. Unfortunately, all fish and seafood are also contaminated with mercury, a brain poison, and the FDA advises that women and children have no more than 12 ounces of fish per week, limited to those which have lower levels of mercury (we have a list in our book).

Fish oil capsules or liquid can provide an additional and safer source of DHA and EPA because the oils are usually distilled to remove mercury and other impurities, and DHA from algae is available for those who do not eat fish. The basic form of omega-3, alpha-linolenic acid, is also good because it can turn into EPA and DHA in our bodies, though not very efficiently. This is found in all green plants, but the best sources are flaxseeds and walnuts, and flaxseed, canola, and walnut oils. Monounsaturated fats, like those in olive and canola oil, also seem to be beneficial for health.

SHAPE: What about "bad fats?" What should we stay away from?
LG: Our current problem is that we have way, way too much omega-6 in our diets . And because our bodies "know" that these fats are essential, it holds on to them. These oils are found mainly in fried foods such as like chips, fries, and commercial baked goods. They are also added to other processed foods to increase the amount of fat, since fat makes foods taste better. As much as possible, limit fast foods , restaurant foods, and processed foods from the supermarket, because these foods tend to have a lot of omega-6 fat.

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The second kind of omega-6 that we get too much of is arachidonic acid, and this is found in meat and eggs from animals (especially poultry) fed on corn and other grains, which are the kinds of meats you usually find in supermarkets.

SHAPE: How important is exercise when consuming the good fats?
LG: There seems to be a positive synergy between exercise and omega-3 fats. Women who exercise more tend to have higher levels of omega-3 in their blood, and those with higher omega-3 levels seem to have a better response to exercise. The amount of omega-3 DHA in the membranes of muscle cells is linked with better efficiency and endurance. Increasing exercise and omega-3 levels together may also help women to lose excess weight.

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