The High Fat, Low Carbohydrate Diet vs. Bicycling for Good Health

After writing my article on diet and health, I thought I had covered the matter and wouldn't return; then I encountered an interview on National Public Radio of a proponent of a high-fat diet, Gary Taubes, which caused me to do some further research into Dr. Aktins' diet and similar low carbohydrate diets. I believe that since I last looked at Dr. Aktins' book back in 1971, he has added a number of new claims, most of them expounded by Gary Taubes, so I thought it would be worthwhile to clear up the matter here. It's important also to look at Dr. Walter Willett's diet, which has been confused with Dr. Atkins'.

The Gary Taubes Interview

On July 7th, 2002, Gary Taubes slandered nutritionists and researchers by saying, "bad journalism never let the facts get in the way of a good story" and that their research was "not real science" but "poorly controlled studies," and accusing them of following "their own pre-conceived notions," and of "demonizing fat."

In his support of a high-fat diet, Taubes said that there was no scientific proof that a low-fat diet is healthier. Yet, in his own article, "The Soft Science of Dietary Fat," Taubes admits, "By the 1970s, each individual step of this chain from fat to cholesterol to heart disease had been demonstrated beyond reasonable doubt," -- and then continues -- "but the veracity of the chain as a whole has never been proven." This reminds me of Lewis Carrol's humorous assault on the syllogism (found in "What the Tortoise Said to Archilles") in which an infinite series of meaningless steps are declared necessary to reach an obvious conclusion.

His comments and attitudes are typical of those who support Dr. Atkins' diet "revolution," which argues that saturated fats are good for you and that carbohydrates are bad. I get letters from supporters claiming that food researchers and nutritionists who disagree with Atkins are Nazis.

Dr. Atkins' View of the Diet Problem

Here is Dr. Atkins' view of diet, health, and fat, as it now exists in the latest edition of his book: Early man ate a healthy meat diet, supplemented with low-calorie vegetables, berries, and fruit. Up until the last century, people ate meals that contained lots of butter and lard, pork, beef, and eggs without any health problems. However, the arrival of soft drinks and white flour in the 1890's created the problem of heart disease and overweight, which had not previously existed. According to Atkins, these highly refined carbohydrates raised insulin levels and created blood sugar imbalance leading to loss of energy, excessive fat accumulations, overweight, heart problems, and eventually full-blown diabetes (elsewhere he condemns white rice, honey, milk, and potato products as well). As the amount of fat in the diet dropped and as the amount of carbohydrate increased, people became fatter and developed more health problems. To make matters worse, overweight people married overweight people, thus producing children even more sensitive to carbohydrates. Nor did nutritional advice -- such as the USDA Food Pyramid -- help, as people were taught to reduce the amount of fat in their diets and eat even more carbohydrates, the opposite of what they should have done.

To solve the problem, Dr. Atkins doesn't want to just eliminate sugar, white flour, white rice, and other refined carbohydrates from the diet but to also strictly limit all other carbohydrate sources too. On his induction diet, carbohydrates are limited to 20 grams (a meat and salad diet), which means that the body quickly runs out of glucose and is forced to burn ketones instead. This diet should last just two weeks; however, he suggests going back to it whenever weight gain has occurred. He also mentions three follow-up diets, but these are almost the same with a somewhat greater allowance for carbohydrates, depending on how much the individual can tolerate without gaining weight. He suggests that for the average person that would be about 40 grams per day. According to Dr. Atkins, once the correct weight is reached, all the usual danger signals found in a blood analysis (high blood sugar, high cholesterol, triglycerides, etc.) will have disappeared.

What's Wrong with Dr. Atkins' Food Explanations?

Let's look at each of the claims that Dr. Atkins makes, as most of them have little merit.

First, his notion that early man ate a high fat, low carbohydrate diet is not based on any evidence. True, early man did kill and eat animals (or, as some researchers think, he scavenged the spoiled meat that meat-eating animals had left behind), so meat was part of the diet, but it is impossible to know what proportion it was. It's clear that our teeth are designed to eat both meat and vegetables and that apes and monkeys also eat a mixed diet. Analysis of the contents of the stomach of the Ice Man, who died 5,000 years ago, establish that he had been eating grains. We know from history and from the Bible that milk, honey, and bread were eaten in quantity back in the days of the pharaohs. In the Bible, bread is the most important food. Jesus asked us to pray for our daily bread, not for our daily steak.

When we look at groups of people pursuing hunter-gatherer or other simple lifestyles today, we do not find that those who eat the most meat are the skinniest or that the ones eating mostly plant foods are the fattest. The following data is from "Food for Thought" by William R. Leonard, from Scientific American, November, 2002. All of the peoples below, except those in the USA, are living rather basic lifestyles. This data also indicates that something besides the choice of animal or plant products in the diet is responsible for the amount of weight carried by the body. Weight is measured as BMI, Body Mass Index, and the higher the number, the greater the weight per height. A BMI of under 18.5 is considered underweight, while a BMI of 25 or above is considered overweight. Ironically, the Inuit (Eskimos), the people with the nearly all-meat diet who inspired the notion that eating meat could keep you thin, are among the heaviest. Looking at these diets, it seems that the total calories is probably more important than their source, with the Evenki being the only strong exception. Leonard points out that the Evenki diet is low in fat (20% fat vs. USA 35%).

Diets and Their Affect on Weight
People	Total kCal	From Animals	From Plants	BMI (Body Mass Index)
Turkana	1,411	80%	20%	18
!Kung	2,100	33%	67%	19
Quechua	2,002	05%	95%	21
Evenki	2,820	41%	59%	22
Inuit	2,350	96%	04%	24
USA	2,250	23%	77%	26

Second, in looking at various cultures, modern and historical, we find those societies with high carbohydrate diets, living on bread, rice, potatoes, corn, and beans, usually do not have the weight problems of modern societies which eat large quantities of meat. Atkins explains this by saying that those counties also do not drink large quantities of soft drinks. That's true, but they do consume large amounts of white rice and white flour, which he also considers responsible for our health problems. Besides, they are certainly not practicing a strict control of their carbohydrate intake, which Atkins considers necessary. If it were somehow strangely necessary for all mankind to eat Dr. Atkins' diet, most of the people on the earth would have to starve, as it takes 16 pounds of grain to produce one pound of beef. Half the people on earth have an income of less than two dollars a day and could not afford a heavy meat diet.

Third, Atkins accuses the introduction of "refined carbohydrates" with causing current health problems and says that these foods were not introduced until the beginning of the century. However, except for corn syrup, introduced in the 80's, all these foods have been around a long time. Refined sugar was introduced into Europe during the Middle Ages, and it was one of the few items taxed by the US government before 1802. Thoreau, as frugal as he was, purchased it for use at Walden Pond. Consumption per person has increased during this century. Honey has been a prized sweet for thousands of years, but the amount consumed even by honey lovers is small. White flour was first produced by the Romans, and its use has actually declined during this century, although there has been a smaller increase since 1970. White rice has been the customary rice of China since the time of Confucius, about 500 BC. It has thus been the standard food in Asia for about 2,500 years, although US comsumption has never been high. No one, except Atkins, would include milk in this category. Its use is ancient. Potatoes are an Amerindian food and have been heavily used as food by other peoples for hundreds of years.

Fourth, Atkins claims that people in the US have become more susceptable to diabetes due to overweight people marrying overweight people within this century. It is true that some people are at greater risk than others due to their greater tendency to gain weight or to acquire diabetes, and it's also true that some populations are more susceptable as well, but these developed over many generations. The weight crisis in the US has occurred within a single lifespan and thus could not be much affected by breeding.

The Recent Rise in Obesity in the USA
Year	1960-62	1971-74	1976-80	1988-94	1999-2000
% Obese	13.4%	14.6%	15%	23.3%	30.9%

Fifth, Dr. Atkins is effective at looking through medical research and finding a few studies that seem to support his claims. However, he completely ignores or dismisses the notion that saturated fats are dangerous. Atkins claims that the medical community supports a low-fat diet because of the financial support of the junk food producers, but he fails to provide any evidence of such support. In fact, all or nearly all nutritionists recommend eating whole grains, beans, vegetables, and fruit rather than eating processed foods. And like him, they consider junk foods and the trans-fatty acids (hydrogenate fats) found in processed foods harmful. It's ironic that Atkins accuses the researchers of being influenced by money, as he makes large amounts of money from the people who read his books, buy his pills, and use his services. His income is so great, in fact, that he has his own CEO (see the right panel).

Sixth, one claim that Atkins makes is that his diet is good for the heart. In fact, he spends a great many pages talking about this, saying that he developed the diet because he is a cardiologist and because his diet helps those with heart problems. Actually, saturated fat, which is a heavy component of his meat-heavy diet, causes heart disease. When Dr. Atkins developed his own heart problems, he kept the information secret from the public, and only a heart attack in a public place caused this information to be released. His agents said that his heart problems should not be publicized because they are a purely personal matter; however, I think that anyone who claims to be an example of his own diet should be completely honest about his condition.

If Dr. Atkins' Explanations Are Incorrect, Why Does His Diet Work?

As I explained in my web article on diet, all the various quick weight loss diets work by creating partial starvation or other unnatural condition, and the Atkins diet is no exception. Normally, the body burns glucose and uses fat as a long-term energy reserve. When carbohydrates are eliminated from the diet, there is nothing to convert to glucose, the body quickly runs out of blood sugar, and begins to starve. In desperation, the body breaks fat down into ketones and uses these as fuel instead. During this process, the body loses large amounts of water, and the appetite is suppressed. Thus the Aktins diet ends up being a low-calorie diet. However, due to the uncontrolled nature of the diet, the dieter is likely to burn protein (i.e. muscle mass) as well as fat.

Atkins makes two contradictory claims about ketosis, the production of ketones in the body. First, he states that ketosis is a highly desirable condition, that ketones are actually better fuel for the body and brain than glucose, and second he argues that ketosis occurs for less than two weeks in the diet, thus not long enough to cause major problems. Both of these claims are incorrect. Not much research has been done into ketosis, but it is known that the process creates problems for the kidneys. Atkins acknowledges that those with kidney disease should not use his diet, but he does not think his diet could cause kidney problems due to the short amount of time a dieter remains in ketosis. But, he elsewhere maintains that a person on his diet who starts to gain weight should induce ketosis once again, thus someone using the Atkins diet could be bouncing in and out of ketosis fairly often. In addition, the National Academy of Science's Institute of Health has determined that the human brain needs the energy produced by 130 grams of carbohydrate per day. Since those following Atkins' maintenance diet are consuming less than 130 grams of carbohydrate per day, they are evidently maintaining their weight by remaining in perpetual partial ketosis. Finally, a high-protein diet is hard on the kidneys and liver, and it may lead to osteoporosis as well.

Aktins maintains that after someone has lost the weight that all the desirable blood factors will be improved, which he credits to his method of losing weight. Medical authorities agree that the blood factors will be improved after losing the weight, but they say that the desirable blood factors result from having achieved a reasonable weight, not from the method by which it was achieved. However, they point out that during the weight loss period, these factors are pushed upwards to dangerous levels. They recommend slower and less risky weight loss methods.

To maintain the appropriate weight using the Aktins method, the dieter must keep the amount of carbohydrates in the diet restricted for a lifetime. Depending on the amount of restriction, this may mean that the person must greatly reduce the consumption of grains, beans, fruit, and vegetables which contain nutrients, antioxidants, phytochemicals, and fiber which are essential for maintaining good health. To resolve this problem, Dr. Atkins suggest purchasing his pills, and he takes 60 pills every day himself. But besides the expense of the pills, we yet don't have a complete understanding of the nutrients supplied by foods, and taking too many of some vitamins can be harmful.

Finally, Dr. Atkins recommends exercise, and he plays a little tennis as a result. However, the extremely low carbohydrate diet results in a body depleted of glucose, and thus a cyclist on the Atkins diet will be in a perpetual state of bonk. This makes a lifestyle with a healthy amount of exercise impossible. Atkins does not acknowledge this problem, but Sugar Busters (another low-carbohydrate diet) does:

One word of caution: If you are a marathon runner or an exercise "fanatic," this diet is probably not for you. High levels of exercise require the foods that generate large quantities of glucose to feed your engine.

Another Approach to Fat

I became aware of Walter C. Willett when National Public Radio used him in attacks on the food pyramid. From the NPR broadcasts, it would be easy to assume that Willett liked nothing about the pyramid and basically agreed with Dr. Aktins. The truth is almost the opposite. Both Aktins and Willett consider trans-fatty acids dangerous, dislike the food pyramid, and have no problem with a high-fat diet, but otherwise they don't agree. Atkins thinks saturated fat is harmless and advocates a diet high in saturated fat based on meat; Willet considers saturated fat dangerous and advocates nuts, fish, and vegetable oil as safe sources. Both have problem with carbohydrates, but Aktins wants them largely removed from the diet, and Willett wants the amount reduced, with only refined carbohydrates eliminated. Atkins does not want fruit included in the diet, while Willett considers it important. Atkins' diet has yet to be tested in a controlled experiment using large numbers of people over a long time, but Willett's diet is based on such tests. All of Willett's conclusions are based on research, but he admits that more research needs to be done.

The best source of information I have found about Willett's diet is "Rebuilding the Food Pyramid," By Walter C. Willett and Meir Stampfer, Scientific American, January 2003. The rest of the information about his diet will come from that source.

Willett emphasizes, "All fats are not bad for you, and by no means are all complex carbohydrates good for you."

He points out that saturated fat from diary products and red meat raises cholesterol levels, as shown by studies with volunteers eating proscribed diets in the 60's. Polyunsaturated fats (from vegetable oils and fish) lower cholesterol levels. Thus, since the 60's, Americans have been taught to replace animal fats with vegetable fats which has helped halve the coronary heart disease rate.

The high coronary heart disease rate found in the US is not found in places where either the amount of fat consumed is small or where the fat is mono- or polyunsaturated. In traditional Japanese diets, fat is only 8 to 10% of the diet, and only about 500 men out of 10,000 develop heart disease. In Crete, the traditional diet contains much olive oil and fish, thus fat constitutes 40% of the diet, but it is mono- and polyunsaturated fat, thus the heart disease rate is only 200 men out of 10,000. In Eastern Finland, on the other hand, saturated fats make up 38% of the diet, and the heart disease rate is 3,000 out of 10,000.

Willett believes that efforts to reduce total fat in the diet and raise carbohydrates have partially caused a shift to processed food, which are high in sugar and transfatty acids.

A look at the two main cholesterol-carrying chemicals, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) reveals another problem with low-fat diets. Raising the LDL/HDL ratio increases risk, decreasing it lowers it. Controlled feeding showed that replacing calories from saturated fat with calories from carbohydrates causes LDL and cholesterol levels to fall, but also causes the HDL level to fall, thus the risk reduction is small. Triglyceride (molecules of fat) levels increase, which increases the risk of heart attack. Giving up mono- or polyunsatuated fat for carbohydrates for carbohydrates is even worse.

Worse than saturated fats are transfatty acids, which raise LDL and triglicerides and drop HDL.

Omega-3 oils, found in fish and some plant oils, reduce the possibility of ventricular fibrillation.

In tests, a high intake of starch from refined grains and potatoes is associated with increase risk for type II diabetes and coronary heart disease. A diet high in fiber reduces those risks. Those who are lean and active can consume large amounts of refined carbohydrates without diabetes or heart disease while the same diet in a sedentary population can be very harmful.

Fruits and vegetables help prevent heart attacks. Red meat increases the likelihood of colon cancer, heart disease, and type II diabetes. Eating fish and chicken instead of red meat reduces the risk of all three. An egg a day is not harmful. Eating nuts is beneficial. Diary products do not reduce risk of osteoporosis; in fact, countries with the highest consumption have the highest levels of fractures. Increased use of diary products raises the risk of prostate and ovarian cancer.

When Dr. Willett tested people with USDA's Healthy Eating Index (which tests how well the diet compares to the food pyramid), he found those with the highest scores had a lower risk. But they also smoked less, exercised more, and had "healthier lifestyles." After adjustment for these factors, there was no advantage.

His advice? Eat healthy fats and cabohydrates, the exact proportion unimportant. Consume moderate amounts of healthy protein. Eat fruits and vegetables in abundance, and nuts and beans daily. Minimize consumption of dairy products, red meat, butter, refined grains, potatoes, and sugar. Avoid transfatty acids. Every day, drink a small amount of alcohol, and take a multiple vitamin.

For those using this diet, he predicts a 30% reduction in cardiovascular disease among women and 40% among men. He does not predict a reduction in cancer risk, which he says comes from weight control and exercise.

Are High Glycemic Foods the Cause of Obesity?

One important point that Aktins and Willett share in common, along with Dr. Ornish, who advocates a high-cabohydrate, low-fat diet, is the notion that sugar, white flour, white rice, and pototoes cause obesity because they have a high-glycemic index. However, James J. Kenny points out some flaws with this argument. First, the Pima Indians living in Mexico weigh much less that Pima Indians living across the border in the US, even though the Mexican Pima Indians eat a diet of mainly potatoes and corn tortillias while the American Pima Indians eat a Westernized diet with lots of fat and protein. Among the Mexican Pimas, type 2 diabetes and obesity is rare, while more than half of the US Pimas have the problem by age 50. Second, it's not just refined carbohydrates that have a high glycemic index. Carrots have the same glycemic index as potatoes, white bread, and sugar. However, carrots have only 195 calories per pound, potatoes 450, white bread 1,250, and sugar 1,750. As a result, it takes a lot more carrots to fill the stomach than it does sugar, and thus carrots tend to satisfy the appetite better than sugar. Some foods high in protein have a high glycemic index even though they contain no carbohydrate. Finally, ice cream has a much lower glycemic index than carrots, potatoes, or white rice, but it has an insulin index similar to potatoes and much higher than white rice (this is due to the high-fat content). He suggests that using a satiety index would lead to more reliable results, but according to such an index, the potato came out on top for satisfying hunger.

My own diet includes pasta, potatoes, white rice, and beans with brown rice, and I can't tell any difference in my appetite or behavior based on which foods I eat, perhaps because I exercise so much. Anyone who wants to experiment can make an individual appraisal by abstaining from high-glycemic foods. But, if high-glycemic foods are not responsible for obesity, what is?

The Cause for the Rise in Obesity

While there have been major changes in the US diet during this century, both good and bad, and we have seen an increase in both the amount of sugar and the amount of saturated fat consumed, the biggest change has been towards a sedentary lifestyle. Children used to walk to school, and many adults walked to work. Jobs that required physical work used to be the norm, now they are rare, and people used to push a hand mower rather than sit on a power mower. Dr. Atkins says that heart attacks started showing up at the beginning of this century. Could that be due to the fact that people were no longer riding bicycles or walking to their destinations but were instead driving automobiles everywhere they went? In my opinion, body weight has increased greatly during the last 15 years because we have eliminated most forms of physical work from our lives. When living a high-stress, sedentary lifestyle, people will actually eat more than they would if working hard.

It has often been said of me that I am naturally skinny, but when I taught for four years at a high-stress school that kept me too busy for much exercise, I found my weight climbed every winter, reaching 193 pounds, twenty pounds above my normal high. During the same period, my brother, who has always been a good bit heavier than me, worked as a common laborer for a while, and thus weighed twenty pounds less than me. The difference in our weight is clearly due to the amount of exercise that we get.

While I can see real benefits to drinking fruit juices rather than soft drinks, eating whole grains rather than refined grains, eating beans on a regular basis, eating a good variety of vegetables and fruits, and avoiding saturated fats and transfatty acids, I think the benefits of such a change would be smaller than if everyone began walking and bicycling for transportation again.

The Benefits of a Healthy Diet vs. the Benefits of Exercise

Dr. Aktins promises you that his diet will help you control weight and will be beneficial for your heart, while Dr. Willett claims that his diet will reduce cardiovascular disease by 30 to 40%. Of course, there would be other benefits from eating a balanced diet, and I think everyone ought to eat wisely. However, the potential health benefits of regular exercise are even greater than those that Dr. Willett offers.

According to "Get Up And Get Moving" in Newsweek, Jan. 20, 2003, one person in four within the USA is complete sedentary, and 60% of the population doesn't get enough exercise to receive a health benefit. The Centers for Disease Control and Prevention estimates 76.6 billion dollars could be saved each year through exercise. (I have seen much higher figures than this elsewhere.)

A Stanford study of 6,000 men showed that ability to last on a treadmill could better predict the risk of death that high blood pressure, smoking, diabetes, high cholesterol, and heart disease.

However, walking slowly doesn't do any good. Bess Marcus, director of physical activity research at Brown Univesity says, "You must walk a mile in 15 to 20 minutes max. You should feel your heart beat faster, your breath quicken, your sweat drip."

By Walking Briskly Three Hours Weekly
Heart disease:	risk 40% lower
Stroke:	risk decreased by 30%
Type 2 diabetes:	risk up to 30% lower
High blood pressure:	prevented or reduced
Osteoporosis and bone fractures:	less common
Colon cancer:	risk reduced
Anxiety and depression:	reduced

For several years, I have been recommending 66 minutes of exercise every day. In the fall of 2002, the National Academy of Science's Institute of Medicine released its recommendations, which include a full hour of moderately intense exercise every day, equal to walking at 4 mph. I am going to do a separate page on the NASIOM report, which I think is definitive of our current knowledge about exercise and nutrition.

The Benefits of Cycling

If walking is good, bicycling is better. Pedalling Health (you can also read my review in this directory) reports that in Finland, those who chose to walk for exercise had a maximum heart rate of 60% and a VO₂ max. of 38. Those who chose to bicycle had a maximum heart rate of 70% and a VO₂ max. of 57. Although starting from a higher level, the cyclists improved more over a ten week period than did the walkers.

According to All-Cause Mortality Associated With Physical Activity During Leisure Time, Work, Sports, and Cycling to Work, the largest study ever undertaken on the benefits of exercise, bicycling to work on a regular basis had the greatest health benefit discovered: "Even after adjustment for other risk factors, including leisure time physical activity, those who did not cycle to work experienced a 39% higher mortality rate than those who did."

People sometimes complain that they are too tired to exercise. The fatigue is caused by a sedentary lifestyle. I bicycle 120 miles and walk 12 miles a week (about two hours of exercise per day), and I never feel tired, although I often did while working at my sedentary job. People also complain that they don't have time to exercise. Go for a walk instead of watching TV at night, and you will have an interesting time. Ride your bike or walk to the store, and you can accomplish your errand and get your exercise at the same time. Even better, use a bicycle to get to work. The time spend walking or cycling will be more than compensated by a longer and more energetic life.

So, my suggestion to anyone who wants to lose weight and/or to improve health is to improve the fruit and vegetable content of your diet, reduce your saturated and hydrogenated fats, and spend more time walking, bicycling, and working around your home. The more exercise you get, the better you will feel and the less trouble you will have maintaining the proper weight.