Junkfood Science: When fat (dare I say it?) is a good thing

June 13, 2007

When fat (dare I say it?) is a good thing

Two new studies have received little notice in the media, perhaps because their findings tell young people caught up in dieting and the desire to be thin, that they need to eat more and have more body fat.

For years, biology professor Anne Loucks, and colleagues at Ohio University have been researching the effects of retrained eating and undereating on teens and young women. Their studies have shown that too few calories disrupt bone formation among women even into their thirties. Their latest research highlighted that hunger and irregular menstrual periods aren’t good indicators of whether women are undereating; and that among those who weren’t eating enough calories, bone formation was suppressed even among those with normal body fat. The problem appeared not just with anorexia, but was especially pronounced among those exercise intensely. “Regular menstrual cycles do not reliably indicate that they are eating enough for what they’re expending,” Dr. Loucks said to the New York Times.

The second study was highlighted by writer Harriet Brown. Last fall, she’d authored a powerful piece in the New York Times on the painful process of trying to help her daughter through recovery from anorexia. “Once the [normal] physiological process of starvation kicks in, the disease takes on a life of its own, unfolding with predictable symptoms, intensity and long-term consequences,” she learned. Her family’s incredible story will go right to the heart of any parent.

On her blog this week, though, she mentioned a new study out of Columbia University looking at preventing relapse among anorexia nervosa patients.

It was an analysis of a small one-year trial of anorectics who had recovered their weight and were randomized to receive either an antidepressant medication or a placebo. All also received individual cognitive behavioral therapy specifically designed to prevent relapse. “A major contributor to the poor prognosis of this illness is the high rate of relapse following initial treatment,” wrote the researchers from New York State Psychiatric Institute/Columbia University Medical Center. “Despite successful weight restoration, 30% to 50% of patients require rehospitalization within 1 year of discharge.” Their findings concurred with other studies and found that anti-depressants were of no benefit in recovering from anorexia.

This new paper found that none of the usual physical measures of successful treatment predicted a sustained clinical recovery — not BMI, subtype of eating disorder, waist-to-hip ratio, serum cortisol or leptin levels. Only “lower percent body fat was associated with poor long-term outcome.”

Mrs. Brown wrote a moving appeal to young people suffering from anorexia:

Repeat after me: Fat is good

....We're so used to thinking of fat as the Ultimate Evil, which must be banished at any cost, that news like this can feel downright shocking. Fat can be not just good but essential. Without it our brains don't work very well. We're supposed to have a certain amount of fat in our bodies.

This is important for those in recovery from anorexia, especially people (like my own daughter) who are naturally athletic and build a lot of muscle mass. Nothing wrong with muscles, but you've gotta have fat, too. Lean muscle mass without body fat is associated with relapse. And that's not what anybody wants.

So repeat after me: Fat is necessary for human life. Fat is not evil. Fat can even (dare I say it?) be a Very Good Thing.

It might seem astonishing that such a simple, common sense message is a revolutionary idea for many young people today. It can be difficult for older adults to realize just how powerful the fear of fat is among young people, and just how dramatically restrictive beliefs have become about how much fat our bodies should have. What healthy bodies, of all shapes and sizes, look like isn't what's most in the media. Most girls and young women, for instance, feel that to be healthy and fit, they need to have body fat percentages so low that they are more in keeping with young boys.

At first, it can be hard to understand the depth of such beliefs among young people. But they've become so common nowadays, that people of all ages accept them; yet, at least Babyboomers and Seniors have had something in their pasts to help keep a balanced perspective. While the cultural and medical admonitions to be thin were building when we were growing up, experts were giving us body fat recommendations that still were considerably higher than young people generally hear today. Back then, women heard that an average healthy twenty-year-old female had 28.7% body fat, by middle age healthy women averaged 38% fat, which increased to 41.5% by age 60. Similarly, guys were told that the average twenty year old man had 11% body fat and the average fifty year old had 25.8%.

Just try to find consumer information close to that today. I spent an entire day, trying every permutation of web search terms, and discovered the internet has been wiped clean of practically anything but the need to have low body fat percentages — percentiles lower than has ever been normal or considered healthy — and the dangers of fat. Admonitions against body fat dominate, saying that too many of us are fat and that just because it’s “normal doesn’t mean it’s healthy.” Today, even mature adults are expected to have body fat percentages of twenty year olds.

Few consumers probably hear about those inconsistencies in studies, such as conducted at St. Luke's-Roosevelt Hospital Center in New York a few years ago which found that middle-aged men and women who had BMIs in “normal ranges, had body fat percentages of 24% and 38%, respectively. And a recent study of Japanese adults, aged 20 to 79, conducted at the Okayama Southern Institute of Health, found that body fat percentages of average, healthy men and women with “normal” BMIs were 25.1% and 34.6%, respectively. And the Greek study on perimenopausal women, which found the average body fat percentages among women with “normal” BMIs was 36.5%. What is humorous is that with each one, even though the adults were all healthy and at government-recommended BMIs, the researchers still said their study revealed that people were too fat, with “undesirably high body fat percentages.”

This sports medicine advisor is not atypical in the extremely low body fat percentages being heard by young people today. Note that what was considered normal and healthy less than two decades ago, is now seen as indicative of disease:

The minimum percent body fat considered safe for good health is 5% for males and 12% for females. The average adult body fat is closer to 15%-18% for men and 22%-25% for women....For men over 25% and women over 32% fat, there is a dramatic correlation with illness and disease.

The drive for thinness has reached extremes, with thinner believed to be ideal and any amount of fat thought to be dangerous and a risk for early death. But this isn’t based on credible science. In fact, according to obesity researcher Dr. Paul Ernsberger, Ph.D., who conducted a review of over 400 studies on the health implications of obesity, “there is widespread agreement that reduced adiposity plays little or no role in ... life-prolonging and cancer-preventing effects.” Even in studies of mutant mice, a number of studies have shown that the heavier animals in each treatment group live longer than the lighter ones, he said. Those mice bred for obesity who are overfed later in life to make them obese still live longer than controls, with “a continuous positive relationship between body weight and longevity.”

In humans, severe food deprivation early in life has many adverse effects and shortens life expectancy....One marker of human aging, the menopause, appears several years later in fat women than in lean women. There is no evidence for retarded aging or prolonged life expectancy in lean or underfed humans.

When Dr. Kim-Anh Do, Ph.D., now professor of biostatistics at MD Anderson Cancer Center and Rice University in Houston, TX, led a large Australian twin study on the predictive factors for menopause, she wrote that it is generally agreed that among contemporary industrialized populations, the age of menopause rises with better nourishment. The association between fatness and slower aging is one few have probably heard about. Yet, “early menopause may be a risk factor for earlier mortality from diseases related to decreased estrogen levels and may promote increased incidence of osteoporosis, heart disease, diabetes, hypertension, breast cancer, osteoarthritis, and autoimmune disease,” said Dr. Do. “Recent results also suggest that irregular menstrual cycles, dieting, and stress (especially in African American women) are also predictive of earlier median age at menopause.”

While kids and young people needn’t be worried sick about what chronic disease may befall them when they get older, many do. And a surprising number are already afraid that their fat means they’re going to die earlier. We shouldn’t be surprised, given the recent popularity of the claim that the effects of long-term obesity have never been seen before and this could be the first generation to die sooner than they’re parents. Researchers at the Centers for Disease Control and Prevention, however, demonstrated this claim isn’t the case. In the CDC’s Epidemiological Follow-up Study following people’s BMI through their lives, they explained that we’ve already seen the long-term effects of obesity on longevity. And what the evidence shows is no association between longevity and BMI, with higher BMIs associated with longer, healthier lives. In today’s anti-fat climate, the fact that the evidence has shown such “obesity paradoxes” for decades sounds unbelievable.

We’ve looked at the fat advantages in cancer and infections, kidney dialysis, diabetes, and cardiac death.

The protective effect of body fat is even seen among people with hypertension, said Dr. Ernsberger, with most studies reporting lower mortality in fat hypertensives than in lean ones. As much as five times difference. The hypertension seen in fat people differs in several says from ordinary essential hypertensin, he said. “Plasma volume and cardiac output are increased while total peripheral resistance is unchanged, in marked contrast to the contracted plasma volume and elevated peripheral resistance characteristic of nonobese essential hypertension.” They have normal stroke volumes and don’t have the elevated peripheral resistance of thinner hypertensives, which compromises blood flow to vital organs such as the kidneys. These differences may be part of the reason why fat people appear to have improved survival of cardiovascular disease.

The bottom line is that we needn’t fear our body’s natural fat — however much and places our genes have determined each of us is to have. It’s there for some pretty wondrous reasons.

© 2007 Sandy Szwarc

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