Big fat lies: The truth about the Atkins diet

In July last year, an article in the New York Times, "What If It’s All Been a Big Fat Lie?" by Gary Taubes, set off the loudest round in the ongoing debate about low-fat versus high-fat diets. The fact that it generated such an uproar shows the power of the Times. But it also shows that lots of people are truly worried and confused about what to eat.

Taubes argues that loading our plates with fatty meats, cheeses, cream and butter is the key not only to weight loss, but to a long, healthy life. He claims that it’s not fatty foods that make us fat and raise our risk of disease. It’s carbohydrates. So, the low-fat, high-carbohydrate diet that most nutrition experts advocate is wrong. And he proposes that high-fat diets, notably that of Dr. Atkins, may be the solution.

Taubes’ article though was filled with half-truths, "what ifs," and muddled science. Here are the facts – and the fictions – in Taubes’ article.

Big Fat Confusions

Taubes’ and Atkins’ claim: People gain weight because carbohydrate-rich foods (everything from rice, bread, and pasta to fruits, vegetables, and sweets) actually make them hungrier.

Fact: There is no evidence that most high-carbohydrate foods stimulate the appetite. Sugary or starchy foods, when eaten by themselves, can cause a spike in insulin level, followed by a drop in blood sugar, and thus may leave some people hungry in an hour or two. But not all carbohydrate-rich foods do this, certainly not most vegetables and fruits, beans, and whole grains, or even starchy foods when eaten as part of a balanced meal. Many high-carb foods are filling and satisfying. And by the way, most people who say they crave carbohydrates or have a "sweet tooth" actually overindulge in foods such as cakes and ice cream, which are actually combinations of fats and sugar.

Claim: Excessive intake of carbohydrates causes insulin resistance and thus weight gain.

Fact: A significant number of people today are insulin-resistant – that is, their cells have become less sensitive to insulin, so the body pumps out more of it. This can progress to diabetes and is associated with a common cluster of disorders – obesity, high blood pressure, low HDL ("good") cholesterol, high triglycerides (dubbed Syndrome X or Metabolic Syndrome). But there’s no evidence that carbohydrate-rich foods cause insulin resistance. Moreover, insulin resistance doesn’t make people fat. Most experts believe that insulin resistance is largely a result of obesity, lack of exercise, smoking, and aging, though there’s also a genetic component.

Claim: The calories in carbohydrate-rich foods lead to more or easier fat storage.

Fact: Again, there’s no evidence for this. A calorie is a calorie, whether it comes from fat, carbohydrates, or protein. And remember, fat contains more than twice as many calories by weight as carbohydrates or protein.

Claim: It has never been proven that a carbohydrate-rich diet can promote weight control or good health.

Fact: Not true. Many studies have shown that the right kind of high-carb diet can help people lose weight and reduce the risk of heart disease, diabetes, and certain cancers. In most countries like the Philippines, where diets consist overwhelmingly of rice, noodles, vegetables, and other carbohydrate-rich foods, people tend to be thinner and have a lower risk of major chronic diseases than their Western counterparts.

Claim: The Atkins diet and other high-fat diets work. In fact, they work better than other diets.

Fact: No one ever claimed that they don’t work in the short term. They work because they are low-calorie diets. You may lose more weight initially, but such diets do not work better than other low-calorie diets in the long term. It doesn’t matter if you cut the calories from fats, carbs, or protein, you’ll lose the same amount of weight. In any case, losing weight is not that hard – keeping it off is.

ATKINS: A Best-Seller Again

For 30 years, until he died last year, Dr. Robert Atkins has been promoting his high-fat, high-protein, low-carbohydrate diet not only for weight loss, but also for disease prevention. Other diet doctors (Eades, Sears, and Heller) advocate their own variations. Such low-carb diets have actually been around for at least a century.

During the first two weeks of the Atkins diet, you eat as much fat and protein – beef, poultry, eggs, bacon, cheese – as you like. But you can hardly eat any carbohydrates (only a few vegetables, such as asparagus, broccoli, and cabbage). You can’t consume any bread, rice, or other grain products, fruit, starchy vegetables, or milk. Eventually in the "maintenance phase," you’re allowed slightly more carbohydrates. The rest is all fat and protein.

During the first two weeks on this diet, weight loss can be dramatic, since most of it is water, not fat. Because of the calorie reduction, you will burn your own fat. Actually, you burn fat all the time, but without carbohydrates, your body does not burn the fat completely, and thus substances called ketones are formed and released into your bloodstream. This condition, called ketosis, makes dieting easier, because it tends to cause nausea, which suppresses appetite. Dr. Atkins considers this state benign, but there is no evidence for this claim. Ketosis poses potential dangers over the long term.

No Wonder You Lose Weight

If you lose weight on Dr. Atkins’ plan after the first two weeks, it’s because it gets you to cut down on calories, despite his claims that this is not a low-calorie diet. He doesn’t specify quantities, but the food choices are very limited so you end up eating less, especially if ketosis continues.

Normally, eating lots of highly saturated animal fats boosts LDL ("bad") and total cholesterol. But the Atkins diet, because it causes weight loss, may actually reduce cholesterol, according to a study at Duke University (subjects averaged only 1,450 calories a day). Other studies have found that such diets can raise cholesterol, at least in many people. Even if your cholesterol level drops once you stop losing weight, it will likely climb back up if your diet is high in saturated fat.

Since 1972, Atkins’ books have sold more than 11 million copies. And yet, when researchers who compiled the US National Weight Control Registry analyzed the diets of 3,000 successful dieters (who lost at least 30 lbs. for more than a year), they found that fewer than 1 percent had used a very-low-carb diet such as Atkins’. If the Atkins diet offered some sort of metabolic advantage for long-term success, surely it should have been better represented.

So Why Not?

There’s virtually no place on earth where people regularly eat such a high-fat, high-protein diet, so there’s no long-term safety record. If you are healthy and stay on the Atkins diet for a few weeks or months, with proper supplements, it may be safe. There are known adverse effects, though: Dehydration, constipation, dizziness, fatigue, nausea, and headaches. The longer you remain on the diet however, even in its maintenance phase, the greater the risks:

• A diet rich in animal fat (and low in plant foods) increases the risk of heart disease, high blood pressure, stroke, diabetes, various cancers (such as colon and prostrate), and diverticulosis (intestinal disorder).

• High intake of animal protein over long periods can increase the risk of liver disorders, and possibly kidney disease and bone loss.

• You can’t get the vitamins, minerals and fiber you need on this diet, so Dr. Atkins recommends supplements – preferably the formula his company markets. But no matter how many pills you take, you won’t get the fiber and the protective phytochemicals found only in fruits, vegetables, and whole grains.

• People with medical problems, such as diabetes or high blood pressure, should consult a doctor when trying any diet.

The bottom line: If you follow an Atkins-style diet, you’ll probably lose weight, but it could be dangerous beyond a few weeks. As with all crash diets, keeping the weight off is the hard part.