Busting the Low-Fat Dieting Myth

January 01, 2000  ·  Michael Fumento  ·  Overweight and obesity

Fat, these days, seems to be nothing but a villain.

You see, telling overweight people to eat less and exercise more might send them fleeing for the hills, so the diet book authors and women’s magazines searched valiantly for some aspect of eating to blame, some way of telling people they can stuff their faces — and still lose weight. They found such a culprit in fat. It seemed to make sense: the fat you eat becomes the fat you wear. And there even seemed to be some science behind it.

And so a fad was launched. In part the attack on fat is justified because of its extra energy-carrying capacity. After all, a gram of fat does have nine calories compared to only four for carbohydrates and protein. Reducing fat intake to reduce calories can be a major factor in weight control. But the centerpiece of the attack against Demon Fat is that even on a calorie-for-calorie basis, there is something especially bad about those calories coming from fat.

"Your body does not manufacture fat," states Susan Powter authoritatively in Stop the Insanity! Rather, ". . . it comes from the end of your fork." If you avoid fat, she says, "You can eat whatever you want, whenever you want it, and however much of it you want. "

Meanwhile The Fat Attack Plan, authored by the same team who wrote that two-million-selling The Fat Counter, asserts that "you don’t have to count calories. All you have to do is learn to identify foods containing fat and eat less of them [emphasis in original]."

The Fat Attack Plan gives the green light to eating sugared cereals: "you may be surprised to learn that our answer is `No, sugared cereals won’t make you fat.’ Not the ones without fat, that is."

"Calories do not count," writes Debra Waterhouse in her best selling 1993 Outsmarting the Female Fat Cell. "What counts is how you eat those calories and where they come from: carbohydrates, protein, or fat."

Some in the popular media have also bought into the calories-don’t-count, only-fat-does thesis, letting it guide their reporting. In 1995 the Center for Media and Public Affairs in Washington, D.C., monitored three months of news coverage from 37 different local and national news outlets to see how they covered issues of food safety and nutrition. The center found that fat consumption attracted twice as much coverage as any other nutritional topic. The media warned against fat consumption four times as often as the over-consumption of calories.

But at least as important as anything the media have done has been the government’s proclamation, in a 1990 report endorsed by a coalition of 38 federal agencies, that we should reduce fat in our diet to 30% or less of total calories. That fat is especially detrimental to weight control is also incorporated into the labeling that the Food and Drug Administration requires on virtually all food products. Right next to where you’re given the number of calories, you’re told which calories come from fat. The label also incorporates the 30%-of-calories-from-fat recommendation.

Has this bombardment affected American eating and shopping habits? A joint Food Marketing Institute and Prevention magazine survey in 1996 found that 72% of those polled made decisions to buy food based on the fat content listed on the label, while only 9% treated calories the same way. In fact, sodium content was rated as more important than calories. An American Dietetic Association survey in 1992 found that many people believe fat should be completely eliminated from the diet. Yet that action would prove suicidal since a small amount of fat is needed to absorb certain vitamins and carry out other bodily functions.

All this Demon Fat propaganda is false. It has changed our eating habits for the worse, devastating our diets and causing scales across the country to creak and groan and beg for mercy under added weight.

A Myth Takes Hold

The history of blaming dietary fat for bodily fat goes back to the turn of the century, when it was wrongly hypothesized that dietary fat passed unchanged through the digestive tract directly to become body fat. But it wasn’t until 1989 that it swept the imagination of the American public. That year saw the publication of The T-Factor Diet, written by Martin Katahn, a psychologist at Vanderbilt University.

"YOU CAN’T GET FAT EXCEPT BY EATING FAT!" exclaims Katahn in The T-Factor Diet in the obnoxious way pitchmen like to put things in all capitals. "You are not going to be cutting calories or counting them," he says. "Except for fat, you are going to be eating just about as much of everything as you want."

Still later he insists, again all in capitals, that magical line that almost automatically leads to best-sellerdom: "FORGET ABOUT CALORIES!" But a funny thing happens later in the book. In a chapter in which he propounds an especially speedy system of weight-loss called the "Quick Melt", he offers a diet that provides "approximately 1,000 calories for a woman, and 1,500 for a man." But wait a second. Didn’t he tell us that "only fat makes you fat" and that we can "forget about calories"?

So how come suddenly we’re counting calories, and not just fat ones, but all calories? Is it true that only fat makes you fat, or do calories count? The answer, as we shall see, is that ultimately all that counts is calories, and that fat-free food will not make you fat free.

Katahn’s thesis was based on two different formulas that began in the medical journals and should have stayed there. Both appear to be scientifically valid, but simply have no relevance to weight loss. One, dietary fat converts more efficiently to body fat than does carbohydrate or protein. Two, carbohydrates, whatever the conversion ratio, rarely become body fat in any case. Rather, they are almost always burned off immediately as fuel.

If you think about it a moment — which, alas, no one ever does — you see that the second formula cancels out the first. It doesn’t really matter that carbohydrates convert less efficiently to body fat, since the conversion rarely takes place at all. Thus we can forget the first part of the formula entirely.

But what about the second part? It turns out that in everyday life, it’s not very important either. What this all means is that the body has priorities. It prefers to get its energy from carbohydrates and store fat as fat. But if you are gaining weight because you’re eating too many calories, even if the number of calories from fat is relatively small, the excess dietary fat will all convert to body fat, rather than any of it being burned off as fuel.

Indeed, if you really eat to excess, even much of the extra carbohydrates will become fat, too. On the other hand, if you’re already overweight, you can be eating virtually no fat and still not lose weight because your body isn’t involved in making new body fat, just maintaining the fat that’s already there.

So how do you lose that body fat? Simple. You either cut your calories or increase your energy expenditure. If your daily intake of calories is too small, your system is forced to convert the fat you eat into fuel, just as it converts the carbohydrates. Your body doesn’t want to use fat for fuel. But by restricting your energy intake (your calories), you restrict its options. Your body must burn off not only the fat you’re consuming but the fat you’re carrying around. So the low-fat diet gurus have it absolutely backward. Calories aren’t irrelevant; ultimately, they’re all that matters.

The scientist whose work was so crucial to Katahn and remains so to the low-fat faddists is a soft-spoken professor of biochemistry at the University of Massachusetts named Jean-Pierre Flatt, M.D. He is the person who came up with the formula for the cost in carbohydrate and fat burning. Katahn specifically cites Flatt’s work.

When I contacted Flatt by phone, it was, truth be known, to pick a fight. Imagine how I felt when I found out the poor man agreed completely with my own findings and had no idea of the misconceptions and deception to which his work has led. "Anybody who eats more calories than he burns is going to gain weight," he told me. "If somebody eats 4,000 calories and burns 2,000, they will retain more of the fat they eat. "

No Clinical Evidence

In all fairness, it must be said that diet gurus aren’t the only ones who have bought into the low-fat myth. Some medical researchers have as well. But a look at some of the same studies these scientists invoke — along with studies they sometimes ignore because they don’t fit with preconceptions — shows that for weight control purposes, yes, all calories are alike.

A few of these studies have been retrospective, looking back at what subjects have eaten, and they seem to find that fatter people eat more fat. But these studies suffer from "recall bias," meaning the researcher is dependent on what the subjects claim to have eaten. Recall is notoriously inaccurate for measuring what people have eaten. The only reliable way of measuring is to do so at the time they’re actually eating.

The methodology is fairly simple. You take two or more groups of people and feed them the same amount of calories. But you vary the amount of fat from which those calories are coming. Then you compare the high-fat eaters with the low-fat eaters and see if there are any differences.

Of these studies, I have found only a few that might lead to the interpretation that eating less fat as a percentage of calories translates into less fat on the body. All show only slight differences, and in each case the reduction in fat intake was drastic. Had it been a mere 33% to 30% reduction, such as the government is trying to get us to make, the differences wouldn’t have shown up at all.

Further, none of this difference may have been due to different levels of fat consumed. The complicating factor is that decreasing fat intake almost necessarily means increasing fiber intake. The only study that recorded this difference gave the low-fat subjects almost twice the fiber as the high-fat ones. Considering the weight-loss benefits of fiber, this may completely account for the difference between the two groups.

Most of the studies on fat content show that persons eating a high-fat diet lost as much body fat as, or even more than, those on the low-fat one. One study, reported in the American Journal of Clinical Nutrition in 1996, compared obese Swiss patients on diets in which 26% of the calories came from fat (45% from carbohydrates) with those on diets in which 53% of the calories came from fat (15% from carbohydrates).

In both groups, total calories were limited to 1,000. If the low-fat myth were no myth, those 53 percenters should have been rolling their way onto the scales. Instead both groups lost the same amount of weight in the same amount of time. The authors concluded it was only the caloric reduction that caused weight and fat loss.

A study at Rockefeller University in New York determined its subjects’ caloric needs, which was given to patients in a liquid formula. But the formulas had differing amounts of fat, ranging from zero all the way up to 70% of total calories. The result? Once again there was simply no difference between subjects. "Metabolically, the difference between conversion of fat or any other food is so minute as to be largely irrelevant to dieters," said the chief author of the study, as reported in The New York Times. "A calorie is a calorie," he added.

Lawrence Kushi and some researchers at Harvard University undertook a survey of non-American data and found no substantiation for the belief that fewer fat calories mean less body fat. "In Europe," they wrote, "southern populations with lower fat intakes display more obesity than do northern populations with higher fat intakes. In China, where fat intake ranges from 5% to 25% of calories, there also has been found no association between percent of calories from fat and body weight."

"The studies are clear," says Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health. "It’s a myth that it’s just the fat in your diet that makes you fat. As far as body fat goes, it doesn’t make any difference where your calories come from."

Despite diet-guru assertions to the contrary, the federal government’s own data show fat consumption — as a percentage of calorie consumption — is declining. The Department of Agriculture has determined that as of the years 1994 to 1996, fat comprised about 33% of total calories in the American diet. This showed a continuing decrease from 34% in 1989 to 1991 and 40% in 1977 to

  1. Thus at the same time our consumption of fat as a percentage of calories was dropping — just as the government was telling us it must — our waistlines were exploding.

Fat consumption dropped 17.5% as obesity increased by 25%. A longer look at fat consumption appeared in a medical journal, comprising studies dating back to the 1920s, showing that even though we’re fatter than ever before, we’re actually getting fewer of our calories from fat.

The Fattening Low-Fat Craze

The low-fat craze is just that. Scientifically it’s utterly bankrupt. But oh, what a craze it is! And until the common knowledge catches up with the science, the food industry will do everything in its power to flood our taste buds and pack our growing bellies with engineered low-fat foods.

It does so with the encouragement of the government. The Department of Health and Human Services’ Healthy People 2000 publication urges that by the millennium there should be an increase to "at least 5,000 brand items [in] the availability of processed food products that are reduced in fat and saturated fat."

It’s impossible to walk down any food aisle without seeing banners proclaiming: LOW FAT! REDUCED FAT! NO FAT! FAT FREE! LITE! AS ALWAYS, FAT FREE! and a dozen other variations. As one network news correspondent put it: "In a world fighting fat, fat-free has become the battle cry." You can even find fruit drinks advertising themselves as fat free, as if a substance comprising nothing but water, sugar, artificial flavoring, and artificial color could possibly have fat in it.

Grocery sales of all low-fat foods amounted to $18 billion in 1993, and have been estimated to grow to $30 billion by 1997. The aforementioned Food Marketing Institute-Prevention Magazine survey asked shoppers about nine types of food engineered to be lower in fat, ranging from salad dressing to cake. It found that for each category, Americans were eating more of the low-fat items in 1996 than in the year before.

Much of this growth has been in the snack food industry. The Snack Food Association reported in 1995 that nearly every company in the $15-billion industry is working on low-fat or reduced-fat products. That category produced less than 5% of the industry’s total sales in 1994 but is expected to grow to a third of the market by 2000, according to the association.

No label is more associated with the low-fat fad than Nabisco’s SnackWell’s line of low-fat and fat-free cookies and other snacks. Although it didn’t even exist before 1992, by 1996 it was producing an amazing $600 million annually in revenues. "I’ve never seen anything like it in the industry," proclaimed a Ray Verdon, president of Nabisco Foods, about the SnackWell’s line. In those four short years, SnackWell’s became America’s most popular cookie.

When SnackWell’s Devil’s Food Cookie Cakes first appeared, demand was so high that Nabisco had to ration them out to stores. Women’s groups formed to scout out the cookies, fights erupted in the stores over the boxes, and grocery store managers kept the snacks under lock and key. These cookies are hardly noncaloric, with 100 calories in a measly little ounce. But people are convinced that if the cakes have no fat they can’t possibly make you fat, so they eat away.

Meanwhile, Hershey somehow manages to pawn off chocolate syrup as a health food. "Because it’s virtually fat free, you can really pour it on," says one of its advertisements. Yes, and with 100 calories in just two tablespoons, you can virtually feel your pants ripping at the seams as you do so. Similarly, Hershey’s premixed chocolate milk is sold in 15.5-ounce bottles that state in bold letters: "99% fat free." That small bottle of fat-free drink delivers 240 nice low-fat calories, so the wide-mouth bottle enables you to down more than a tenth of a day’s calories in a matter of seconds.

Of course, the food industry rakes in megabucks from people thinking they can eat twice as much as they did before and not worry about gaining weight. But while industry counts its money, health professionals are horrified.

"I think the greatest myth is that fat-free means calorie-free and that means I can eat all I want," says Robert Kushner, director of the University of Chicago Nutrition and Weight Control Clinic. "If people only pay attention to fat, they will drift to fat-free products that are high in calories."

"While people who want to drop weight have decreased dietary fat, they’ve also become volume eaters, giving in to a second or even a third bagel because they’re using no-fat cream cheese," says registered dietitian Cathy Nonas, director of the Theodore Van Itallie Center for Weight Control at St. Luke’s-Roosevelt Hospital Center in Manhattan.

"I have so many people who come to me and say, ’I’m eating only healthy food. I’ve really cut out the fat, and I still can’t lose weight’," says Colleen Pierre, a Baltimore registered dietitian and a spokeswoman for the American Dietetic Association. "Because we think only fat counts, we think that if food has no fat in it, it’s okay to eat all you want."

Laboratory tests, as well as anecdotes, provide evidence that people eat more when told what they’re eating is low in fat. In one test, 17 volunteers were given meals consisting of a variety of low-fat, low-calorie foods. When the subjects were told the meals were low fat and low calorie, they pigged out. When told they were eating high-fat and high-calorie foods, they carefully restricted what they ate. And these were persons who were selected because they hadn’t dieted in at least the previous six months.

Dieters would presumably fare much worse because they are always looking for an excuse to eat. A 1996 survey found a third of shoppers admitting that they felt it was OK to eat more of a food because it was low in fat or had no fat. My guess is most of the other two-thirds fibbed.

Aside from the pig-out factor, there are other problems with this increased intake of low-fat foods. One is that, as we have seen, low-fat or no-fat may be extremely high in calories. A fat-free eight-ounce glass of grape drink has a whopping 200 calories in it and can be downed in seconds. Many of the new foods engineered to be low fat or fat free have as many or almost as many calories as they replace. This is partly because the fat was only a small component anyway. Reduce a small part by a small part, and you really don’t have much reduction. Further, manufacturers often pump up the sugar content to make up for the taste lost from the shortening.

"People are basically substituting sugar for fat," says Marion Nestle, head of the New York University Department of Nutrition. "As people focused on eliminating fat, food marketers came up with fat-free substitutes. But the substitutes they provided were equally as fattening."

SnackWell’s Devil’s Food Cookie Cakes lists three of its first four ingredients as sugar. Thus, one calorically dense ingredient is simply swapped for another. Here are a few examples in which fat-free means little in calorie reduction:

Cracker Jack

120 calories in 28 grams 110 calories in 28 grams

Oreo cookies 160 calories in 32 grams 140 calories in 33 grams

Vic’s Gourmet Popcorn 150 calories in 30 grams 130 calories in 30 grams

Skippy peanut butter
190 calories in 32 grams 180 calories in 35 grams

Kraft shredded cheese
110 calories in 30 grams 90 calories in 31 grams

Sometimes the reduced-fat version has just as many or more calories as the original or the full-fat competitor. SnackWell’s reduced-fat Chocolate Creme Sandwich Cookies have slightly fewer calories per gram than Oreos, but because they’re slightly bigger they actually have more calories per cookie. The Sourdough Unsalted Hard Pretzels from Snyder’s of Hanover, while fat free, actually have substantially more calories than the original.

In theory, reduced-fat foods, usually being also slightly reduced in calories, could help make a difference in weight control if you swapped exactly the same amounts of food. But even then it wouldn’t be of much help. That’s because the reduced-fat foods on the market today are almost exclusively what is known as "peripheral foods, or things you shouldn’t be having much of anyway. Yes, if half your diet was potato chips and sandwich cookies, reduced-fat Lay’s and reduced-fat Oreos might help you lose weight if you swapped evenly chip for chip, cookie for cookie. But if half your intake is cookies and potato chips, you’re in a lot of trouble one way or the other.

The Secret: Low-Density Eating

Having read this far, you may now be shocked to hear that eating a low-fat diet can actually be a tremendous boon to weight loss and control if you use it as a means to an end, and not an end in and of itself. That’s because fat has more than twice as many calories, for the same amount of weight, as carbohydrates or protein. By swapping carbohydrates or protein for fat, you can reduce your calorie intake, and the reduced calorie intake will help you lose weight.

Here’s the basic rule and probably the most important sentence in this article: Don’t reduce the percentage of the calories you’re eating that are coming from fat: reduce the fat in your diet in order to reduce the number of calories you’re eating.

The way you do this is by eating foods that are naturally low in fat. By "naturally," I’m not making a case for organic foods or only buying your food at places with names like "Alfalfa’s" or "Sprouts" or "Green Things." I mean foods that haven’t been processed, and especially those that haven’t been processed to be low-fat in order to replace higher fat products. The problem with most of those, as I’ve noted, is that they’ve used sugar to replace fat. Sugar, like fat, is calorically dense. You’re just replacing one high-calorie item with another.

Consider, for example, an orange versus a glass of orange juice. The juice is an orange in processed form. It has about 80 calories in a six-ounce glass. Like any liquid, it has little satiating effect on hunger; in fact, you get as much satiation from a glass of water, which has no calories. But an average-size California Valencia orange in its unprocessed form, which is to say simply an orange, has just 60 calories and sits in your stomach a long time while your digestive system works to break it down and pass it through the intestines. Part of the satiating effect comes from the high amount of fiber in oranges. Most orange juice has had the fiber completely removed.

How about spuds? Potatoes are a naturally low-calorie, highly nutritious food. Many Irish used to live practically on potatoes alone (though admittedly not through choice). A pound of unpeeled potatoes has only 289 calories. Processed into potato chips, one of the unhealthiest foods ever discovered, they have an incredible 2,400 in a single pound. Peanuts are high fat and high calorie in their natural form, but processing makes them that much worse. A half cup of raw peanuts has 430 calories, but processed into peanut butter a half cup has a whopping 780.

The more you process a food, the more bulk and fiber you take out of it and the more calories you leave. What you’re left with is less satisfaction and satiety per calorie. Thus in one study, subjects either ingested whole apples, apple puree (which contained the same amount of fiber as a whole apple), or fiberless apple juice. The ones who ate the whole apples were most satisfied, while those who drank the juice were least satisfied.

Converting to a natural, low-fat diet can make a huge difference in how many calories you consume. Demonstrating this was a Cornell University study in which three groups of women were given fairly similar food each having a different level of fat: 15% to 20% of calories from fat, 30% to 35%, and 45% to 50%. Those on the low-fat diet consumed an average of 2,087 calories daily, while those in the middle range consumed 2,352 daily, and the high-fat eaters ate 2,714 calories a day.

And does eating fewer calories on a diet low in energy density translate into weight loss? Of course. It has to. Calories always count. They are all that count. Another Cornell study compared women on a high-energy dense diet with those on a low-energy dense one and allowed both to eat as much as they wanted of the foods allowed them. The second group ate far fewer calories and lost 5.5 pounds in 11 weeks, twice the weight loss of the women eating foods that had a high energy density.

What are we to make of all this? Simply that it isn’t just fat that’s the bad boy in our diets; it’s anything that has lots of calories relative to its bulk. Fresh fruit is good, but dried fruit is not so good because all the bulkiness provided by water has been squeezed out. White bread isn’t as good as whole wheat because part of the bulk provided by fiber has been removed. A 70-calorie cookie isn’t as good as a 70-calorie banana regardless of whether it’s a fat-free cookie, because the banana is big and heavy and bulky and the cookie can be popped down your throat like nobody’s business and followed quickly by another.

The foods that are highest in energy density contain no fat whatsoever. They are soft drinks and juices. A glass of water and a glass of a soft drink sweetened with sugar, such as Kool-Aid or soda pop, have exactly the same bulk. But while the glass of water contains no calories, the sugar-sweetened soft drink contains about 140 calories in a 12-ounce glass. Furthermore, for most people soft drinks are more palatable than plain water, making it clear that soft drinks can play an important part in making you fat. This is not so important in countries such as those in Europe where standard soft drink sizes are around eight ounces. But in the United States where the smallest size in theaters is 20 ounces, where machines now dispense 20 ounce sodas, and where mini-marts sell bathtubs containing 64 ounces of soda, soft drinks can play a key role in popping your britches.

All of this isn’t to advocate eliminating all processed foods from your diet. I, for one, would consider life not worth living if peanut butter were not available. But recognize that processed foods that are dense in energy are bad actors. If you’re eating a lot of them and are having trouble controlling your weight, don’t wonder why.

Every year Americans gobble up more processed low-fat foods, and every year they grow fatter. The low-fat fad must end now.

Calculate your BMI to see if you are obese. What the scores mean:

  • 24 or under: Minimal health risk
  • 25-29: Low to moderate risk
  • 30 or over: High risk