What Your Doctor Hasn't Told You About Low-Calorie Diets

© 2008 Jonni Good

For years we've been told that we get fat because we eat too much, and we'll lose weight when we eat less. That's the theoretical basis for almost every reduced calorie diet you've ever tried.

The theory seems obvious - but it isn't actually true. It's only 'obvious' in the way that it was once 'obvious' that the Earth is flat. Careful scientific study has never been able to prove that low-calorie diets work.

In fact, highly respected scientists proved they don't work in the early 1900's. We are only now beginning to hear about these studies in the national press, because most 'leading authorities' have ignored them.

Even more importantly, the authorities also ignore the historic evidence that obesity is a modern illness. Instead of looking for the foods in our modern diet that cause us to gain too much weight, scientists, obesity experts and doctors usually blame us for not having enough self-control to stay thin. They say you can eat anything as long as you cut back on the calories.

In this article you'll read why this assumption about calories and obesity is incorrect. You'll see why you inevitably gain weight after the diet is over. And even more importantly, some of these dietary mistakes can cause nutritional deficiencies in both adults and children, and can lead to chronic illnesses such as heart disease, diabetes and cancer. 

And low-calorie diets can lead to the sugar cravings that plague so many of us, and which contribute to the illnesses associated with insulin resistance and the metabolic syndrome.

Myth #1: Fat People Eat Too Much

Although this is a universally believed statement, it can only be true if overweight people eat more then thin people do. If, in fact, thinner people eat as much or more than overweight people, the number of calories can't be the true cause of the growing obesity epidemic.

Author Gary Taubes has looked into this issue, and found some surprising facts in the scientific literature.

Taubes is a correspondent for the magazine Science, and has received three Science in Society Journalism Awards from the National Association of Science Writers. He spent five years reviewing all the available studies and scientific reports about obesity, heart disease, diabetes, and other chronic illnesses that are known to be related to the food we eat. He published his surprising conclusions in his latest book - Good Calories, Bad Calories.

In this book he states that many overweight people say they actually eat less than their thin friends and neighbors, and they're often right.

He refers to a report called Diet and Health, Implications for Reducing Chronic Disease, available through the National Academy Press, which states that, calorie for calorie, most overweight people actually eat less than people of normal weight.

But they may eat different foods, or have genetic differences that cause them to store more of their food as fat.

In the last hundred years, many highly-qualified scientists have questioned the assumption that weight gain is caused by excess calories. The idea that fat people eat more than thin people has been disproved in several well-designed studies by highly respected scientists. But the myth holds on in the minds of doctors and obesity experts everywhere.

Why? Because it seems so obviously true that too much food will make you fat. When obesity experts do look at the source of calories, instead of total calories, they tend to blame calories from oils and fats. Their reasoning is simple – gram for gram, fat has more calories than carbohydrates or proteins. Therefore, it must be the fat calories that make us gain weight. This theory also sounds reasonable, but it has never been proven.

If you've ever watched a political debate, you know it's human nature to ignore evidence that would prove you wrong - and doctors and scientists are just as human as the rest of us.

But how can we blame our excess weight on eating too much, if we don't actually eat any more calories than thin people do?

The assumption that we're fat because we eat too many calories naturally leads to the next myth about diet and weight loss:

Myth #2: Low-Calorie Diets Will Help You Lose Weight

In a perfect world, we would judge the effectiveness of any diet by several important criteria:

• Does it help you lose weight?
• Does it improve your health and help you live longer?
• Are there no side-effects or nutritional deficiencies while using the diet?
• Do people enjoy the food?
• Does the lost weight stay off?

Most reduced-calorie diets accomplish only the first item on that list, and that's why most diet book authors say, right in the introduction to their books, that diets don't work.

You do lose weight, of course, if you eat less than your body needs for fuel and maintenance. This is probably why most people assume that it's just obvious that a low-calorie diet is the answer to a weight problem. It's also the reason that many people go back on the same low-calorie diet that they used in the past, because they know it 'worked'. We give credit to the diet when we lose weight, and we blame ourselves when we gain it all back again.

But there are known side-effects of a low-calorie diet that everyone should know about before they start cutting their calories. And one of the natural side effects is gaining extra weight after the diet is over.

In Good Calories, Bad Calories, Mr Taubes brings our attention to a study conducted in 1917 by the director of the Carnegie Institution of Washington's Nutrition Laboratory, Francis Benedict. The study was published under the title Human Vitality and Efficiency Under Prolonged Restricted Diet.

A similar study was done in 1944 at the University of Minnesota. The results were published in 1950 in the book The Biology of Human Starvation.

What really happens on a 'well-balanced' low-calorie diet?

The Carnegie Study

The 1917 study was designed to find out if humans could thrive mentally and physically on a low-calorie diet. During the study careful records were kept of the psychological and physical symptoms encountered by a group of young male volunteers who were put on reducing diets of 1400 to 2100 calories a day. They stayed at this level for a month, in order to lose an average of 10% of their starting body weight. After the initial weight loss, the men were kept on reduced-calorie diets for two months so they would keep their weight at this new level.

If you have ever been on a 'well balanced' reduced-calorie diet in order to lose weight, the results of this study will sound familiar to you.

Symptoms: The 10% weight loss occurred, as expected. However, the 12 men in the study constantly complained of a gnawing hunger, and they said it was almost impossible to stay warm, no matter how much clothing they wore.

Their metabolism slowed down so much that they would begin to regain weight if the daily calorie level went up over 2100 calories, even though they ate far more than that before the study started. Their blood pressure and pulse rate went down, they became anemic, they had difficulty concentrating, and physical activity made them weak.

One symptom must have been extremely upsetting to these young healthy men - their interest in sex was reduced, and in some cases it vanished completely.

Many of these symptoms occurred only a few days after beginning the low-calorie diet.

After the diet was over: Once the three month study was over, the volunteers were cautioned against over-eating, but they seemed unable to stop themselves from doing just that. They felt strong cravings for anything sweet, and indulged in every snack they could lay their hands on.

Within two weeks, these young men were back at their original starting weight, and then gained an average of eight more pounds, making them heavier than they were before their diet.

The University of Minnesota Study

The University of Minnesota study had similar results. The purpose of the study was to document the physical and psychological effects of starvation.

It was 1944, and the US military knew that many communities in Europe had been cut off from normal food supplies for many months. They expected allied troops to find many starving people when Europe was liberated. They wanted to know how best to respond to the physical and mental problems these communities were suffering from because of poor food supplies.

Conscientious objectors volunteered for the study. Many of them were Quakers who later went to Europe to help rebuild the war-torn countries.

The volunteers agreed to eat a diet averaging around 1570 calories a day, consisting mostly of starchy, plant-based foods like whole-wheat bread, potatoes, and turnips, along with a bit of cabbage. Approximately 400 calories a day of protein were allowed in the form of meat or dairy products.

In order to duplicate the conditions they expected to find in a liberated Europe, the volunteers were also required to walk five or six miles a day.

Symptoms: The physical and psychological symptoms were even more pronounced among the volunteers of this study, probably due to the exercise. The men lost weight, of course, but in addition -

• Their hair started to fall out.
• Small cuts took longer to heal.
• Their metabolism slowed down and they rarely moved when they didn't have to.
• They felt cold all the time.
• They had slower reflexes.
• They felt weak.
• Their normal interests in the world around them narrowed.
• They suffered from depression, irritability and food obsessions.
• And, like the volunteers in the 1917 study, they lost their interest in sex.

Two volunteers showed psychological symptoms bordering on psychosis, and one volunteer was committed to the psychiatric ward at the local hospital because of threats of suicide and violence.

After the diet: When the starvation part of the study was over, the men were kept on a diet of 3000 calories a day to avoid the dangerous binge-eating that followed the Carnegie study in 1917.

Even on this higher calorie diet, the volunteers felt desperately hungry, and many found their depression getting worse. One volunteer became so psychologically unstable during this phase of the study that he attempted self-mutilation.

When the volunteers were finally allowed to eat as much as they wanted, they sometimes ate as much as 8000 calories a day, but still felt hungry. When they were checked one year after the beginning of the study, the men weighed an average of 5% more than they did when the study started, and had 50% more body fat.

How these studies compare to modern reducing diets:

In these two studies, the average daily calorie intake was 1400 to 1600 calories.

In a recent article titled Treatment of Obesity: An Overview, which I found on the American Diabetes Association's Clinical Diabetes website, a low-calorie diet (LCD) for women has 1000 to 1200 calories a day, and for men 1200 to 1600 calories a day - the same number of calories - or lower - than the starvation studies we just read about. Many popular magazine articles suggest these lower caloric levels, as so some of the popular diet plans that sell pre-made diet food along with weekly meetings.

For those who fail to lose weight at this calorie level, (because the patient's metabolism slows down in response to starvation), a very low calorie diet is suggested in the American Diabetes Association's article. The VLCD are only prescribed when the patient can stay at a clinic for constant medical monitoring. These VLCDs provide 200 to 800 calories a day, usually given as a liquid formula diet. Exercise is also recommended, along with behavioral modification.

Most fad diets, like the cabbage soup diet, encourage people to go on very low calorie diets on their own, without medical supervision. These fad diets are just as dangerous as the ones prescribed by doctors.

Where are the warning labels?

After reading the list of psychological and physical symptoms experienced by the volunteers in those two studies, you can see why behavioral modification and counseling, along with constant medical attention, would be needed by anyone attempting one of these low or very low calorie diets.

But most people start a reduced calorie diet after reading an article in a magazine about the newest way to lose weight, or we join a club like Weight Watchers. Even when the diet is prescribed by your doctor, it is rare to receive as much attention that the volunteers in those low-calorie diet studies received.

Yet I've never read a notice, in any diet book, that cautions readers about the possibility of depression, psychosis, food obsessions, and a loss of interest in sex. That warning wouldn't sell many books, would it?

And you can also see why the long-term success rates are in the 1% to 5% range. Most people, like the healthy volunteers in the Carnegie and University of Minnesota studies, end up heavier than they started.

If that's happened to you (and it's happened to almost everyone who has tried to lose weight by cutting calories), your doctor probably thinks you don't have enough will power.

Maybe you don't think you have enough will-power, either. But these two studies, and others like them, have proven that your will-power has nothing to do with it.

Gaining weight is just one of the many negative physical and psychological consequences of a low-calorie diet.

What's the answer?

Did you know that our food used to contain powerful fat-fighting compounds that actually help fat melt away while you build more muscle? Many of these foods are on the current 'do not eat' lists, because doctors and obesity experts have forgotten that people eating these natural foods didn't get fat.

The right kind of diet can also act as a natural appetite suppressant, curb your cravings for sugar and other simple carbs, and help increase your muscle mass. (Low-calorie diets cause the loss of muscles).

For more information, please visit my new website at www.CravingControlDiet.com