BlogHer caught up with William D. Lassek, M.D., and Steven J.C. Gaulin, Ph.D., co-authors of BlogHer Book Club's pick, Why Women Need Fat for more information on what women eat and how it affects them, especially as they age.
BlogHer: Your book focused a lot on consuming more naturally-sourced foods, including animal and dairy products. Do you have any suggestions for people who do not consume animal products, such as vegans?
William Lassek & Steven Gaulin: In general, most studies show that vegetarians are less likely to gain excess weight than those who eat meat. However, when we compare American women who say they are vegetarians with those who eat meat, their weights do not differ very much. This may be because of the large amount of vegetable oil high in omega-6 fat in the American diet.
One reason that vegetarians may benefit from not eating meat is that they get less of the active form of omega-6, arachidonic acid, which is a strong promoter of weight gain. However, because American women are also more likely to have more vegetable oils, which are high in a form of omega-6 which can turn into arachidonic, it is especially desirable for them to choose oils like canola, walnut, olive, and flaxseed and to avoid foods which “may contain” oils other than canola or olive oil. Flaxseeds and flaxseed oil are high in the basic form of omega-3 and canola and walnut oils are moderately high.
Vegetarians are more likely to have low omega-3 levels in their blood, especially the most active form, DHA, which is most abundant in fish or seafood. For those vegetarians who eat eggs, choosing high omega-3 eggs is very desirable. If they do not eat fish, DHA supplements made from algae are available and are very desirable. A web search for “DHA from algae” will provide many choices. If possible, they should aim for 750 mg to 1000 mg a day of DHA with similar amounts of the next most active form of omega-3, EPA. Taking supplementary DHA is especially important for women who may have children in the future and for those who are pregnant and nursing. Supplements for their infant children after weaning may also be desirable.
BlogHer: Your bibliography is impressive (something I appreciate in a book) and definitely helped back up your surprising claims. How long did it take to research and write this book?
William Lassek & Steven Gaulin: We have been working together on the research that ultimately led to this book for eight years, analyzing detailed data from more than 20 different national and international data sets. Since there is are so many different and opposing ideas and opinions about weight and dieting, many of which have surprisingly little evidence supporting them, we felt it was very important to make sure that all of our ideas were supported by hard evidence from our own research and the research of others. That doesn’t mean that we are correct about everything, because all scientific ideas are subject to relentless and constant criticism and so inevitably undergo change, refinement, and improvement. But it’s still the best method we have for trying to get at the truth. What we say in our book is as up-to-date as we could make it.
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BlogHer: Some of our reviewers have commented on the fact that they are struggling to reconcile the idea that animal fats and full-fat foods, in moderation, are not bad for us. As one person put it, they'd been programmed to believe that animals fats are bad for us and that low-fat is good. Do you have any advice for the people who are really struggling with the concept that full fat foods aren't as bad as we were raised to believe?
William Lassek & Steven Gaulin: We can certainly sympathize with this struggle, because we have keenly felt it as well. For the past fifty years Americans have been indoctrinated with the idea that animal fat is bad for us, so it is not easy to suddenly confront the possibility that this may not be true. But up until forty or fifty years ago, animals were the major source of fat in the human diet. Since the Stone Age, our richest source of fat has been animal fat, and getting that fat was one of the main reasons that our ancestors scavenged and hunted for meat. Millions of years ago our ancestors where breaking open the bones and skulls of grass-eating animals with stones to get at the fat inside. Without the energy and nutrients animal fat provided, we would never have been able to grow and support a brain seven times larger than other animals. Most importantly, animal fat from grass-fed animals is relatively high in the omega-3 fats we need to support those large brains, while fat from fish and seafood is even better. And for the last ten thousand years, meat and milk from domesticated animals, fish, and eggs have been a major source of the nutrients we need to live and thrive. Those with poor access to these foods were usually stunted, malnourished, and either died in childhood or shortly thereafter.
The unnatural fear of animal fat is largely an American preoccupation; as we explain in our book, this is largely the result of a tireless campaign by one man and the opportunistic exploitation of this campaign by processed-oils producers. In France, for example, animal fat today provides a quarter of all the calories in the diet, and its share is one-and-a-half times greater than in the U.S. Their share of calories from butter alone is four times greater than ours. Now, consider that the age-adjusted death rate from coronary disease in France is one half that of the United States and that only one in fifteen adult women there are obese compared with one in three American women. Other European countries also have much more animal fat and lower heart disease and obesity rates than ours. This is not to say that the French are healthier and thinner than we are because they eat much more animal fat, since there are several other ways in which their diets are better than ours, but it helps to illustrate the point that animal fat is not so bad. It is also likely that a diet high in animal fat is more satisfying, though this has not yet been scientifically investigated.
That said, it is also important to stress that the animal fat that the French and other Europeans eat is not the same as the animal fat Americans eat today, although it is similar to what we used to have forty years ago. Because our animals are usually now fed corn instead of grass, our meat, milk, and eggs are much higher in omega-6 fat and much lower in omega-3 fat than they used to be. This is unfortunate, because omega-6 promotes weight gain while omega-3 reduces it. So we are not urging women to eat lots of fat from corn-fed animals. But it is not the saturated fat in corn-fed meat that is the problem, but the high omega-6 and low omega-3.
This change in the way our animals were fed was considered to be a good thing at the time. Because it increased the amount of polyunsaturated (mostly omega-6) fat, this was thought to be beneficial, and it was also cheaper to raise large numbers of animals in feed lots than pasture.
BlogHer: In Why Women Need Fat, you state that diets don't work. It's a bold statement considering everywhere I turn someone is trying to sell me on a new diet regime or a new diet product. If diets don't work, why do we keep buying into the idea that they will?
William Lassek & Steven Gaulin: One thing Will learned when he was practicing medicine is that the more different treatments there are for a condition, the less effective any of them are. So why do we keep doing something over and over again and expect a different result from all the other times? Part of the reason is that any kind of diet that results in our getting less calories than we use will force us to burn fat and lose weight. So in one sense, all diets are successful. If you stick to a diet for more than a few days, you will lose weight. And when we are losing weight we feel a rewarding sense of pride and accomplishment. The problem, of course, is that for almost all dieters, the weight they lose not only all comes back, but they often end up weighing more than when they started the diet. Many studies have shown that women who diet more, gain more weight over time than those who diet less. Since 1999, almost two-thirds of American women have tried to lose weight in any given year, and they have gained an average of two pounds a year—more than the women who do not diet. (For more on the reasons why diets fail, see our recent blog on the Psychology Today website and our book.)
BlogHer: Many women find after pregnancy they are more active and actually have an easier time keeping weight off than before they had kids. How do you think activity level plays in to the idea that women are biologically programmed to gain weight after childbirth?
William Lassek & Steven Gaulin: During her pregnancy, the average American woman gains more than thirty pounds, with five to ten pounds of that being added fat. After her baby is born, and especially if she nurses, that new fat quickly melts away, along with some of the fat she had before she became pregnant. So losing weight is usually easy for much of the first year and even longer in women who keep nursing. During this period, a woman naturally eats less than she needs to maintain her weight, especially with her increased activity level. The reason for this is that her body wants to release the omega-3 fats stored in her body fat—fats which are critical for the growth and development of her baby’s brain. Regardless of her diet, most of that omega-3 comes from her stored fat.
However, over the next five or ten years, almost all women will gain weight, because this is beneficial to any other children they may have. In fact, the rate at which women naturally add weight is actually greatest in their 20’s and 30’s and then starts to slow down. And we find that this is true in every group of women in countries where extra food is available: women in their late teens typically weigh around 120 pounds, and women in their late 40’s typically weigh 145 to 150 pounds (20 pounds less than the average American woman today). Much as we might wish it were not so, this pattern is normal, natural, and programmed into women’s genes. And while her activity levels may increase after having a baby and may help her to lose weight, this does not protect her from the natural weight gain that usually follows over time. Our brains are very good at adjusting our food intake to our activity level to keep our weights where it wants them to be. Women who don’t have children often also begin to gain weight in their 30’s at an even faster rate, for reasons that we explain in our book.
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